The human heart is a pear-shaped structure about the size of a fist. The heart is an amazing organ. It is responsible for supplying the body with oxygenated blood. Each time the heart beats, it exerts a pressure on the veins and arteries called blood pressure. Blood pressure is extremely important and must be controlled if it is too high or low. Blood pressure can be controlled by medication prescribed by your doctor, proper exercise and a diet filled with plants and vegetables.
The heart is made of a special kind of muscle called myocardium, and is enclosed in a double-layered, membranous sac called a pericardium.
The heart lies in the chest cavity between the lungs. It is composed of four chambers, many large arteries and many veins. The four chambers are called atrium and ventricles. A wall of muscle divides the heart into two cavities: the left cavity pumps blood throughout the body, while the right cavity pumps blood only through the lungs. Two chambers of the heart lie in the left cavity and two chambers lie in the right cavity.
The two upper chambers of the heart are called atrium, the bottom chambers are called ventricles. The right side of the heart receives deoxygenated blood from all parts of the body except for the lungs. The left side of the heart receives oxygenated blood from the lungs and pumps it to the rest of the body. An adult heart beats approximately 100,000 times a day, pumping about 2,000 gallons of blood. It has been estimated that the heart will beat about 3 billion times during a 70 year lifetime.
Your heart pumps nearly five quarts of blood through your body every 60 seconds.
Given the heart's arduous task of supplying the body with blood every day, it must be well taken care of. A heart that is improperly cared for may develop heart disease. Heart disease is the leading cause of death among Americans.
Each year there are more than 1.1 million heart attacks in the United States. Unfortunately, of these heart attacks, 250,000 are sudden, causing the patient to die within an hour. Heart disease is often treated by eating foods with low cholesterol, weight loss, exercise and medical treatment. If you would like to know if weight loss will decrease your chance of heart disease, determine your body mass index. Intake of healthy foods like oranges, avocados, and broccoli will also decrease the possibility of developing heart disease.
Heart Attack and strokes are the outward signs of heart disease, namely the accumulation of arterial plaque which slowly constricts or closes arterial passageways, causing life threatening conditions. Heart disease does not happen overnight, but is a life-long progression.
The heart responds to many heart and circulatory conditions by enlarging up to 4 times its normal size. An enlarged heart is common in atrial fibrillation and long standing high blood pressure patients.
Athlete's heart
"Athlete's heart" is a common term for an enlarged heart associated with repeated strenuous exercise. Due to the increased workload required of it, the heart will increase physiologically by enlarging its chambers and muscle mass, thus increasing the volume of blood pumped per stroke. As a result, the heart has to contract less frequently and at rest will beat as few as 40 times per minute. The average number of beats per minute in a non "athlete's heart" is 70 beats. "Athletes heart" is not pathological, and there is usually no danger of cardiac disability arising from it.
Thursday, November 12, 2009
Hernia
HERNIA
A hernia is a protrusion of an organ or tissue through an abnormal opening in the body. Most hernias occur when a piece of intestine slips through a weakness in the abdominal wall creating a bulge you can see and feel. Hernias can develop around the naval, in the groin, or any place where you may have had a surgical incision. Some hernias are present at birth. Others develop slowly over a period of months or years.
There are two main types of hernias: hiatal and inguinal.
Hiatal Hernia
A hiatal hernia can be caused by many different things. Some of the causes are: obesity, pregnancy, tight clothing, sudden physical exertion, such as weight lifting straining, coughing and abdominal injury.
Symptoms of Hiatal Hernia
Most hiatal hernias cause no symptoms.
Inguinal Hernia
An inguinal hernia occurs in the groin. The groin is the area between the abdomen and thigh. It is called "inguinal" because the intestines push through a weak spot in the inguinal canal. The inguinal canal is a triangle-shaped opening between layers of abdominal muscle near the groin. Some of the causes of inguinal hernias are: obesity, pregnancy, heavy lifting, and straining to pass stool can cause the intestine to push against the inguinal canal.
Symptoms of Inguinal Hernia
Some of the symptoms of inguinal hernia are: a lump in the groin near the thigh; pain in the groin. In severe cases, partial or complete blockage of the intestine might occur.
Who gets Hernias?
According to the National Center for Health Statistics, approximately five million Americans have hernias. Hernias in the groin area (inguinal hernias) are most common in men, primarily because of the unsupported space left in the groin after the testicles descend into the scrotum. Hernias in the femoral area, at the top of the thigh, occur most often in women. They commonly result from pregnancy and childbirth.
Will the hernia go away?
No. An untreated hernia will not get better or go away on its own.
A hernia is a protrusion of an organ or tissue through an abnormal opening in the body. Most hernias occur when a piece of intestine slips through a weakness in the abdominal wall creating a bulge you can see and feel. Hernias can develop around the naval, in the groin, or any place where you may have had a surgical incision. Some hernias are present at birth. Others develop slowly over a period of months or years.
There are two main types of hernias: hiatal and inguinal.
Hiatal Hernia
A hiatal hernia can be caused by many different things. Some of the causes are: obesity, pregnancy, tight clothing, sudden physical exertion, such as weight lifting straining, coughing and abdominal injury.
Symptoms of Hiatal Hernia
Most hiatal hernias cause no symptoms.
Inguinal Hernia
An inguinal hernia occurs in the groin. The groin is the area between the abdomen and thigh. It is called "inguinal" because the intestines push through a weak spot in the inguinal canal. The inguinal canal is a triangle-shaped opening between layers of abdominal muscle near the groin. Some of the causes of inguinal hernias are: obesity, pregnancy, heavy lifting, and straining to pass stool can cause the intestine to push against the inguinal canal.
Symptoms of Inguinal Hernia
Some of the symptoms of inguinal hernia are: a lump in the groin near the thigh; pain in the groin. In severe cases, partial or complete blockage of the intestine might occur.
Who gets Hernias?
According to the National Center for Health Statistics, approximately five million Americans have hernias. Hernias in the groin area (inguinal hernias) are most common in men, primarily because of the unsupported space left in the groin after the testicles descend into the scrotum. Hernias in the femoral area, at the top of the thigh, occur most often in women. They commonly result from pregnancy and childbirth.
Will the hernia go away?
No. An untreated hernia will not get better or go away on its own.
Liver
LIVER
The liver is the largest glandular organ of the body. It weighs about 3 lb (1.36 kg). It is reddish brown in color and is divided into four lobes of unequal size and shape. The liver lies on the right side of the abdominal cavity beneath the diaphragm. Blood is carried to the liver via two large vessels called the hepatic artery and the portal vein. The heptic artery carries oxygen-rich blood from the aorta (a major vessel in the heart). The portal vein carries blood containing digested food from the small intestine. These blood vessels subdivide in the liver repeatedly, terminating in very small capillaries. Each capillary leads to a lobule. Liver tissue is composed of thousands of lobules, and each lobule is made up of hepatic cells, the basic metabolic cells of the liver.
What is its major function?
The liver has many functions. Some of the functions are: to produce substances that break down fats, convert glucose to glycogen, produce urea (the main substance of urine), make certain amino acids (the building blocks of proteins), filter harmful substances from the blood (such as alcohol), storage of vitamins and minerals (vitamins A, D, K and B12) and maintain a proper level or glucose in the blood. The liver is also responsible for producing cholesterol. It produces about 80% of the cholesterol in your body.
Diseases of the Liver
Several diseases states can affect the liver. Some of the diseases are Wilson's Disease, hepatitis (an inflammation of the liver), liver cancer, and cirrhosis (a chronic inflammation that progresses ultimately to organ failure). Alcohol alters the metabolism of the liver, which can have overall detrimental effects if alcohol is taken over long periods of time.
Hemochromatosis can cause liver problems.
Medications that negatively effect the liver
Medications have side effects that may harm your liver. Some of the medications that can damage your liver are: serzone, anti-cancer drugs (tagfur, MTX, and cytoxan), and medications used to treat diabetes.
Serzone is a prescription drug manufactured by Bristol-Myers Squibb for the treatment of depression.
The possible side effects of Serzone are: agitation, dizziness, clumsiness or unsteadiness, difficulty concentrating, memory problems, confusion, severe nausea, gastroenteritis, abdominal pain, unusually dark urine, difficult or frequent urination, fainting, skin rash or hives yellowing of the skin or whites of the eyes (jaundice) or a prolonged loss of weight or loss of appetite.
If you or a family member have suffered serious side effects or a fatal injury after taking Serzone, you or the family member may be eligible to file a claim against the manufacturer. You should contact an attorney that specializes in class action lawsuits immediately.
To help prevent liver damage, let your doctor know about your liver condition when being treated for other conditions. Medications come in many forms and it is best to find out what is in them and what it can do to your liver.
Appendicitis
APPENDICITIS
Appendicitis is inflammation of the appendix, a small pouch attached to the cecum, the beginning of the colon, on the lower right side of the abdomen. The appendix is not necessary for life, but it can become diseased. If untreated, an inflamed appendix can burst, causing infection and even death. Appendicitis can affect people at any age. It is most common in people ages 10 to 30.
The cause of appendicitis is usually unknown. It may occur after a viral infection in the digestive tract or when the opening connecting the large intestine and appendix is blocked. The inflammation can cause infection, a blood clot, or rupture of the appendix. Because of the risk of rupture, appendicitis is considered an emergency. Anyone with symptoms needs to see a doctor immediately.
Symptoms of Appendicitis
The most common symptoms of appendicitis are:
• pain in the right side of the abdomen
• nausea
• vomiting
• constipation
• diarrhea inability to pass gas
• low fever that begins after other symptoms
• abdominal swelling
• anorexia
The pain usually begins near the navel and moves down and to the right. The pain becomes worse when moving, taking deep breaths, coughing, sneezing, and being touched in the area.
Not everyone with appendicitis has all the symptoms. People with symptoms of appendicitis should not take laxatives or enemas to relieve constipation because these medicines could cause the appendix to burst. Pain medicine can mask symptoms that the doctor needs to know about, so it should not be used before consulting a doctor when appendicitis is suspected.
The doctor bases an appendicitis diagnosis on symptoms, a physical exam, blood tests to check for signs of infection such as a high white blood cell count, and urine tests to rule out a urinary tract infection. Usually doctors use CT scan or ultrasound to see whether the appendix looks inflamed.
If the diagnosis of appendicitis is not certain, people with equivocal signs of appendicitis may be watched and sometimes treated with antibiotics. People with definite appendicitis have surgery to remove the appendix, which is called an appendectomy. Doctors may use laparoscopic surgery for appendectomy. This technique involves making several tiny cuts in the abdomen and inserting a miniature camera and surgical instruments. The surgeon then removes the appendix with the instruments, so there is usually no need to make a large incision in the abdomen. People can live a normal life without their appendix--changes in diet, exercise, or other lifestyle factors are not necessary
The Appendix is a worm-shaped appendage that sticks out from the top portion of the large intestine.
The appendix can become inflamed. If an inflamed appendix is not treated immediately, the appendix can burst.
What is the Main Function of Appendix?
The main function of the appendix is unknown.
Diseases and Conditions of the Appendix
Appendicitis and Carcinoid Syndrome are the most common conditions that affect the appendix. Appendicitis is inflammation of the appendix.
Carcinoid syndrome is a condition where caracinoid tumors grow in the appendix. The tumors may spread to other parts of the body.
Adrenal Glands
ADRENAL GLANDSThe adrenal glands are endocrine glands that produce hormones. A hormone is a chemical messenger. Each hormone influences specific organs or tissues, thus regulating a certain body process.
The adrenal glands are shaped like a boomerang and located on top of each kidney. The adrenal glands are about the size of the end of your thumb.
The adrenal glands produce hormones that affect almost every system in your body. When the adrenal glands fail to work properly, serious diseases and disorders can develop.
One of the hormones that the adrenal glands secretes is called adrenaline. Adrenaline produces a sudden and remarkable burst of energy.
Outer and Inner layer
The adrenal glands consists of two portions: the inner core (medulla) and the outer layer (cortex).
The inner core of the adrenal gland produces hormones called catecholamines. The 2 most important catecholamines are: adrenaline and noradrenaline. Physical and emotional stress usually trigger their release. When secreted into the bloodstream, adrenaline and noradrenaline increase heart rate and blood pressure. Adrenaline often produces a sudden and remarkable burst of energy.
The outer layer of the adrenal gland produces hormones called corticosteroids.
There are three types of corticosteroids.
1. Sex Hormones.
o Male androgens and female estrogens.
o They affect sexual development and reproduction.
o Sex hormones are also produced in larger amounts in the testicles and ovaries.
2. Glucocorticoids
o Hormones that aid in the conversion of starchy foods into glycogen.
o An important glucocorticoid is cortisol. Cortisol helps regulate the immune system, helps maintain proper blood pressure and blood volume, and helps the body deal with physical stress.
3. Mineralocorticoids
o Control the body's content of the minerals sodium and potassium.
Eyes
EYE
An eye is a round-shaped organ that works with the brain to provide us with vision. The shape of the eye is maintained by the pressure of the aqueous humor. The aqueous humor is the fluid that fills the front chamber of the eye.
Function of the Eye
The main function of the eye is to work with the brain to provide us with vision. The eye and brain translate light waves into a sensation we call vision.
Eye Parts
The eye has many parts. Some of the main parts are listed and described below.
• lens
o The transparent crystalline lens of the eye is located immediately behind the iris.
• cornea
o The cornea is a transparent dome which serves as the outer window of the eye. The cornea is the most powerful structure focusing light entering the eye.
• retina
o The retina is the innermost layer of the eye. It is composed of nerve tissue which senses the light entering the eye.
o The retina sends impulses through the optic nerve back to the brain, which translates the impulses into images that we see.
o There are 4 types of light-sensitive receptors found in the retina
1. rods
2. cones that absorb long-wavelength light (red)
3. cones that absorb middle-wavelength light (green)
4. cones that absorb short-wavelength light (blue)
• pupil
o The pupil is the hole in the center of the eye where light passes through.
• iris
o The iris is the colored part of the eye. It is a thin diaphragm composed mostly of connective tissue and smooth muscle fibers. The iris lies between the cornea and the crystalline lens.
• optic nerve
o The optic nerve is a continuation of the axons of the ganglion cells in the retina. It acts acts like a cable connecting the eye with the brain.
o The optic nerve is also called the cranial nerve II.
• sclera
o The sclera is the white, opaque portion of the eye. It provides protection and serves as an attachment for the extraocular muscles which move the eye.
Eye Doctor
An eye doctor is called an opthamologist. Periodic eye examinations by an opthamologist is the best defense against eye disease. You can also receive eye care from an optometrist or optician.
An optometrist is a college graduate who has received 4 years of training and is licensed to diagnose and treat vision problems and prescribe glasses and contact lenses.
An optician is a person trained to prepare and fit glasses after an opthamologist or optometrist has examined your eyes and prescribed vision correction.
Diseases/Conditions of the Eye
Some common conditions that afflict the eye are listed below.
• Glaucoma
• Farsightedness
• Nearsightedness
• Pink Eye
• Sty
• Blindness
• Astigmatism
• Tumors
• Infections
• Cataracts
• Dry Eye Syndrome
• Macular Degeneration
• Ectropion
• Entropion
• Bumps on the eyelid
Warning Signs of Eye Problems
• Difficulty adjusting to darkness
• Double vision
• Red eyes
• Crusty or swollen eyes
• Recurring pain in or around the eyes
• Excessive tearing or watering
• Very dry, itchy or burning eyes
• Loss of peripheral vision
• Dark spots in the center of your viewing area
• Change in color of the colored part of your eye
• Vision that suddenly becomes blurred or hazy
Kidney
KIDNEY
In humans, the kidneys are two small organs located near the vertebral column at the small of the back. The left kidney lies a little higher than the right kidney. They are bean-shaped, about 4 in. (10 cm) long and about 21/2 in. (6.4 cm) wide.
What is its major function?
They kidneys have a couple of different functions. The main purpose of the kidney is to separate urea, mineral salts, toxins, and other waste products from the blood. The kidneys also conserve water, salts, and electrolytes. At least one kidney must function properly for life to be maintained.
Diseases and Conditions of the Kidney
Some of the most common kidney diseases and conditions are: polycystic kidney disease, nephrosis, lupus nephritis, diabetic nephropathy, rhabdomyolysis, kidney stones, and renal tubular acidosis.
Polycystic kidney disease (PKD) is an inherited disease characterized by the growth of numerous cysts filled with fluid in the kidneys.
Nephrosis is a kidney disease characterized by lesions of the epithelial lining of the renal tubules. The lesions cause a disturbance in the filtration function of the kidney. As a result, large amounts of protein is found in the urine.
Lupus nephritis is an inflammation of the kidney caused by systemic lupus erythematosus (SLE), a disease of the immune system.
Diabetic Nephropathy is a kidney condition that occurs only in people with diabetes mellitus. It results in progressive damage to the small filtering units of the kidney (glomeruli). About 20-30% of people with diabetes develop diabetic nephropathy.
Glomerulonephritis is a type of kidney disease caused by inflammation of the internal kidney structures.
Pyelonephritis is an infection of the kidney and the ureters.
Rhabdomyolysis is a disorder involving injury to the kidney. It has been linked to the drug crestor.
A kidney stone is a hard mass developed from crystals that separate from the urine and build up on the inner surfaces of the kidney. Kidney stones occur in roughly one in 10 people in the United States. Once a person gets more than one stone, others are likely to develop.
Renal tubular acidosis (RTA) is a disease that occurs when the kidneys fail to excrete acids into the urine, which causes a person's blood to remain too acidic.
Kidneys and Diabetes
Diabetes is the most common cause of kidney failure, accounting for more than 40 percent of new cases. High blood pressure, or hypertension, is a major factor in the development of kidney problems in people with diabetes.
Lungs
LUNGS
The Lungs are paired organs in the chest that perform respiration. Each human has two lungs. Each lung is between 10 and 12 inches long. The two lungs are separated by a structure called the mediastinum. The mediastinum contains the heart, trachea, esophagus, and blood vessels. The lungs are covered by a protective membrane called the pulmonary pleura.
Lung function normally peaks in the late teens and early twenties. After the early twenties, lung function declines about 1 percent a year over the rest of a person's lifetime. Lung function decreases about 2 percent a year for people who smoke.
What do your Lungs do?
Your lungs do a vital job. Each day, you take about 23,000 breaths, which bring almost 10,000 quarts of air into your lungs. The air that you breath in contains several gases, including oxygen, that your cells need to function. With each breath, your lungs add fresh oxygen to your blood, which then carries it to your cells. The main function of your lungs is respiration.
What is Respiration?
Respiration is the process of oxygen from incoming air entering the blood, and carbon dioxide, a waste gas from the metabolism of food leaving the blood.
Steam rooms and your lungs
The warm, moist air in a steam room helps clear and sooth your nasal passages, throat, and lungs, making it easier for you to breathe.
Diseases that affect the Lungs
Mesothelioma and asbestosis are diseases that affect the lungs. They are caused inhalation of asbestos.
Common infectious diseases of the lung include pneumonia, tuberculosis, lung cancer, cystic fibrosis, and emphysema.
A pulmonary embolism is a sudden blockage in a lung artery.
Chronic Beryllium Disease is a serious and sometimes fatal lung disease.
Silicosis is very serious and sometime fatal lung disease.
Black Lung Disease is a disease that often affects coal miners
Friday, November 6, 2009
Body’s Cells
The Body’s Cells
Cells are the body’s building blocks. It takes billions of these tiny living units to make just one body. Each cell contains the information needed to build and operate the human body. Although different types of cells have their own shape, size, and job, all share the same basic structure.
STRUCTURE OF A CELL
A living cell is made up of a thin outer membrane, or skin, that surrounds a watery gel called cytoplasm. All the other minute cell parts float in the cytoplasm. The control center of the cell is called the nucleus. The nucleus contains the information needed to keep a cell alive and working properly.
BUILDING BLOKS
Every day the body makes billions of new cells by a process called cell division. Some new cells are needed to replace old, worn-out ones. Others make the body grow. Cell division takes place in three main stages.
Cells are the body’s building blocks. It takes billions of these tiny living units to make just one body. Each cell contains the information needed to build and operate the human body. Although different types of cells have their own shape, size, and job, all share the same basic structure.
STRUCTURE OF A CELL
A living cell is made up of a thin outer membrane, or skin, that surrounds a watery gel called cytoplasm. All the other minute cell parts float in the cytoplasm. The control center of the cell is called the nucleus. The nucleus contains the information needed to keep a cell alive and working properly.
BUILDING BLOKS
Every day the body makes billions of new cells by a process called cell division. Some new cells are needed to replace old, worn-out ones. Others make the body grow. Cell division takes place in three main stages.
LOOKING AT CELLS
Each type of cell has its own shape and size, depending on what job it does. Cells are so tiny that you can only see them by using a microscope. A microscope magnifies the
AMAZING FACTS
Bone marrow cells do not last very long they divide just hours after they are made. But many nerve cells can last a whole lifetime.
Bone marrow cells do not last very long they divide just hours after they are made. But many nerve cells can last a whole lifetime.
Wednesday, October 28, 2009
Coma
COMA
What is a Coma?
Coma is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli. Coma is not a disease. It is a symptom of a disease or a response to an event, such as a severe head injury, seizure or metabolic problem. Most comas do not last longer than four weeks. Some people in a coma shift to a persistent vegetative state, in which breathing, maintaining normal blood pressure, digesting and eliminating foods continues without the patient's awareness. The vegetative state can last for years or decades. The outcome of a coma ranges from full recovery to death. Whether a person recovers, and to what extent, depends upon the cause of the coma and the type and extent of the brain damage.
A coma involves two different concepts: Reactivity and perceptivity.
The perceptivity concept refers to responses of the nervous system to learned stimuli. These types of stimuli may be learned through language or communication skills.
The reactivity concept refers to the inborn functions of the brain. These functions include the eyes, ears, responses to pain, wakefulness and turning ones head toward a sound of movement. These movements are also called reflexive movements.
A person in a coma does not experience reactivity or perceptivity. The patient can not be aroused by calling their name or experiencing pain.
Symptoms of a Coma
The main symptom of a coma is the inability to be aroused to consciousness. Other symptoms are: Lack of self-awareness, Lack of a sleep-wake cycle, Lack of purposeful movements, Lack of suffering and Impaired breathing.
What Causes a Coma?
A coma can be caused by a variety of things. The most often cause of coma is severe head injury. Other causes are: consumption of a very large amount of alcohol (toxic or metabolic coma), diabetes, morphine, shock or hemorrhage. Treatment varies depending on the cause. Overall, in coma cases, damage to the brain's "thinking, and life support centers" have occurred. When damage has occurred, bleeding in the brain, swelling and congestion of the damaged tissue is present. In extreme cases, brain swelling is so great that portions of the brain must be forcible squeezed out of the skull. This dead or "dying" tissue is then surgically removed. An alternative to squeezing portions of the brain out of the skull is to saw off the skull and place it in a cold storage to better accommodate the swollen brain.
Generally, coma is commonly a result of trauma, bleeding and/or swelling affecting the brain. Inadequate oxygen or blood sugar (glucose) and various poisons can also directly injure the brain to cause coma.
Trauma
Minor head injuries can cause brief loss of consciousness, but the brain is able to turn itself back on. Similarly, patients with seizures become unconscious - but gradually waken relatively quickly. Those people who cannot respond after head injury usually have had significant force applied to their head and brain.
The skull is a rigid box that protects the brain. Unfortunately, if the brain is injured and begins to swell (edema), there is no room for the additional fluid. This causes the brain to push up against the sides of the skull and it then compresses. Unless the pressure is relieved, the brain will continue to swell until it pushes down onto the brain steam, which then damages the RAS, which subsequently affects blood pressure and breathing control centers.
The affect of trauma on the brain is not predictable. It may or may not cause significant injury. If the brain is shaken, shear injury may occur, where the nerve connections within the brain are damaged. Coma may occur even with a normal CT scan in this situation. Similarly, head trauma may cause swelling of the brain without any bleeding, and coma may be the result.
Head trauma can cause different types of brain injury. The injury can occur to the brain tissue itself or may cause bleeding to occur between the brain and the skull. Computerized Tomography (CT) of the head can identify most bleeding from trauma.
Bleeding (Hemorrhage)
Intracerebral hemorrhage (intra= within + cerebral=brain + hemorrhage=bleeding) may be small, but it is associated swelling that may cause damage
What happens during a coma?
There are different stages of a coma. Most people believe that a person in a coma is in a deep sleep. This is not entirely true. Some stages of coma resemble a deep sleep but not all. The progress of coma is measured by the patient's increasing awareness of external stimuli. There are many levels of coma which the patient will pass through as functionality increases. Depending on the stage, a person in a coma may make movements, sounds and experience agitation. Coma patients may also have reflex activities that mimic conscious activities. Sometimes, coma patients must be restrained to prohibit them from removing tubes and IVs.
Emerging from a Coma
When a person begins to emerge from a coma, they begin to react to certain stimuli. However, to regain consciousness, both reactivity and perceptivity must be present. Reactivity and perceptivity are necessary for a state of awareness. It is often the case that some parts of perceptivity such as speech and self care must be relearned.
A beneficial Coma
Sometimes a coma may be chemically induced by a doctor to aid in medical treatment and recovery. This usually happens during a head injury.
Coma Statistics
Every ten minutes head injury claims the life of another child.
Head trauma is the number one cause of death and disability among people between the ages of 1 and 44.
About 5% to 10% of all coma patients are incapable of conscious behavior, and end up vegetative, which most of the public think of as prolonged coma.
What is a Coma?
Coma is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli. Coma is not a disease. It is a symptom of a disease or a response to an event, such as a severe head injury, seizure or metabolic problem. Most comas do not last longer than four weeks. Some people in a coma shift to a persistent vegetative state, in which breathing, maintaining normal blood pressure, digesting and eliminating foods continues without the patient's awareness. The vegetative state can last for years or decades. The outcome of a coma ranges from full recovery to death. Whether a person recovers, and to what extent, depends upon the cause of the coma and the type and extent of the brain damage.
A coma involves two different concepts: Reactivity and perceptivity.
The perceptivity concept refers to responses of the nervous system to learned stimuli. These types of stimuli may be learned through language or communication skills.
The reactivity concept refers to the inborn functions of the brain. These functions include the eyes, ears, responses to pain, wakefulness and turning ones head toward a sound of movement. These movements are also called reflexive movements.
A person in a coma does not experience reactivity or perceptivity. The patient can not be aroused by calling their name or experiencing pain.
Symptoms of a Coma
The main symptom of a coma is the inability to be aroused to consciousness. Other symptoms are: Lack of self-awareness, Lack of a sleep-wake cycle, Lack of purposeful movements, Lack of suffering and Impaired breathing.
What Causes a Coma?
A coma can be caused by a variety of things. The most often cause of coma is severe head injury. Other causes are: consumption of a very large amount of alcohol (toxic or metabolic coma), diabetes, morphine, shock or hemorrhage. Treatment varies depending on the cause. Overall, in coma cases, damage to the brain's "thinking, and life support centers" have occurred. When damage has occurred, bleeding in the brain, swelling and congestion of the damaged tissue is present. In extreme cases, brain swelling is so great that portions of the brain must be forcible squeezed out of the skull. This dead or "dying" tissue is then surgically removed. An alternative to squeezing portions of the brain out of the skull is to saw off the skull and place it in a cold storage to better accommodate the swollen brain.
Generally, coma is commonly a result of trauma, bleeding and/or swelling affecting the brain. Inadequate oxygen or blood sugar (glucose) and various poisons can also directly injure the brain to cause coma.
Trauma
Minor head injuries can cause brief loss of consciousness, but the brain is able to turn itself back on. Similarly, patients with seizures become unconscious - but gradually waken relatively quickly. Those people who cannot respond after head injury usually have had significant force applied to their head and brain.
The skull is a rigid box that protects the brain. Unfortunately, if the brain is injured and begins to swell (edema), there is no room for the additional fluid. This causes the brain to push up against the sides of the skull and it then compresses. Unless the pressure is relieved, the brain will continue to swell until it pushes down onto the brain steam, which then damages the RAS, which subsequently affects blood pressure and breathing control centers.
The affect of trauma on the brain is not predictable. It may or may not cause significant injury. If the brain is shaken, shear injury may occur, where the nerve connections within the brain are damaged. Coma may occur even with a normal CT scan in this situation. Similarly, head trauma may cause swelling of the brain without any bleeding, and coma may be the result.
Head trauma can cause different types of brain injury. The injury can occur to the brain tissue itself or may cause bleeding to occur between the brain and the skull. Computerized Tomography (CT) of the head can identify most bleeding from trauma.
Bleeding (Hemorrhage)
Intracerebral hemorrhage (intra= within + cerebral=brain + hemorrhage=bleeding) may be small, but it is associated swelling that may cause damage
What happens during a coma?
There are different stages of a coma. Most people believe that a person in a coma is in a deep sleep. This is not entirely true. Some stages of coma resemble a deep sleep but not all. The progress of coma is measured by the patient's increasing awareness of external stimuli. There are many levels of coma which the patient will pass through as functionality increases. Depending on the stage, a person in a coma may make movements, sounds and experience agitation. Coma patients may also have reflex activities that mimic conscious activities. Sometimes, coma patients must be restrained to prohibit them from removing tubes and IVs.
Emerging from a Coma
When a person begins to emerge from a coma, they begin to react to certain stimuli. However, to regain consciousness, both reactivity and perceptivity must be present. Reactivity and perceptivity are necessary for a state of awareness. It is often the case that some parts of perceptivity such as speech and self care must be relearned.
A beneficial Coma
Sometimes a coma may be chemically induced by a doctor to aid in medical treatment and recovery. This usually happens during a head injury.
Coma Statistics
Every ten minutes head injury claims the life of another child.
Head trauma is the number one cause of death and disability among people between the ages of 1 and 44.
About 5% to 10% of all coma patients are incapable of conscious behavior, and end up vegetative, which most of the public think of as prolonged coma.
STROKE
What is a stroke?
A stroke is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain. Blockage in blood flow or loss of blood causes the brain to lack oxygen and blood nutrients.
The brain requires a constant flow of blood to work properly. If the blood flow is disrupted, brain cells do not receive enough oxygen, resulting in cell death. The degree of damage that results from a stroke is dependent on where and how much blood flow to the brain is interrupted.
A stroke can be a sy
mptom of a serious condition such as brain cancer.
A stroke is also called a cerebrovascular accident, cerebrovascular disease or CVA.
Categories of Strokes
There are two major categories of stroke: hemorrhagic and ischemic. Within the major categories are different kinds of strokes.
In ischemic strokes, there is a blockage of blood flow to the brain. About 80% of all strokes are ischemic. Ischemic strokes usually occur when a blood clot forms in a blood vessel in the brain or neck. Blood clots can also travel from other parts of the body, such as the heart, to the neck or brain and cause a stroke. A blood vessel that is extremely narrowed can also cause an ischemic stroke.
In hemorrhagic strokes a blood vessel in the brain is leaking or broken. These types of strokes accounts for approximately one out of five strokes. Hemorrhagic stroke is
associated with a higher death rate than ischemic stroke. Hemorrhage can occur from a weak or thinned out area on the artery wall that balloons out over time, and then ruptures.
Kinds of Strokes
A stroke may also develop paralysis in one or both sides of the body.
How Does a Stroke Occur?
A stroke occurs when a blood vessel bringing oxygen and nutrients to the brain bursts or becomes blocked. Vessels can be blocked by blood clots or other particles. When blockage occurs, nerve cells in the part of the brain that is deprived of oxygen becomes dysfunctional. When the nerve cells become dysfunctional, the part of the body that is controlled by these cells is also unable to perform.
What Causes a Stroke?
Several different mechanisms may result in stroke: thrombus formation, embolus, and hemorrhage.
Thrombosis formation is an obstruction within an artery resulting from the gradual accumulation of plaque (atherosclerosis). If large enough, the obstructions may restrict or completely block blood flow through the artery. Blockage of arteries supplying the brain causes stroke if alternative routes are not available to deliver an adequate blood supply
Embolus is an obstruction of an artery due to material formed elsewhere in the body (such as the heart). The materials are usually generated in one part of the body and travels throughout the body until it becomes trapped in a blood vessel. The blood vessel then is unable to supply the brain with blood and nutrients.
Hemorrhage results from a rupture of a blood vessel located in the brain. Blood erupts at high pressure in the brain or in tissue surrounding the brain. Normal brain cells may be destroyed. The presence of blood often results in severe headache, lethargy, or coma.
Multiple Factors. Most strokes are associated with atherosclerosis, high blood pressure, oxygen damage or a combination of the three.
Medication. Some medications may increase the risk of developing a stroke. Vioxx, a medication used to treat arthritis was pulled off the market in September 2004 because it is linked to strokes and heart attacks.
What Does a Stroke Effect?
Stroke affects different people in different ways, depending on the type of stroke, the area of the brain affected and the extent of the brain injury. Brain injury from a stroke can affect the senses, motor activity, speech and the ability to understand speech, behavioral patterns, thought patterns, memory and emotions. Paralysis or weakness on one side of the body is common.
A stroke survivor may cry easily or experience sudden mood swings, often for no apparent reason. This is called emotional liability. Laughing uncontrollably also may occur but isn't as common as crying. Depression is common, as stroke survivors may feel less than "whole."
A stroke can also affect seeing, touching, moving and thinking, so a person's perception of everyday objects may be changed. Stroke survivors may not be able to recognize and understand familiar objects the way they did before. When vision is affected, objects may look closer or farther away than they really are, causing survivors to have spills at the table or collisions when walking.
Strokes may cause people to have problems understanding speech. They also may have trouble saying what they're thinking. This is called aphasia. Aphasia affects the ability to talk, listen, read and write. Aphasia is most common when a stroke weakens the body's right side.
A related problem is that a stroke can affect muscles used in talking (those in the tongue, palate and lips). Speech can be slowed, slurred or distorted, so stroke survivors can be hard to understand. This is called dysarthria and may require the help of a speech expert.
After a stroke, the individual often has difficulty thinking clearly. Planning and carrying out even simple activities may be hard. Stroke survivors may not know how to start a task, confuse the sequence of logical steps in tasks, or forget how to do tasks they've done many times before.
Signs of a Major Stroke
Some of the signs of major stroke are facial weakness, inability to talk, loss of bladder control, difficulty in breathing and swallowing, and paralysis or weakness, particularly on one side of the body.
Risks of developing a Stroke
Some of the most common risks of developing a stroke are:
A history of high blood pressure
heart disease
smoking
atherosclerosis
diabetes
migraine headaches
high levels of tryglycerides (a fatty substance in the blood)
use of birth control pills
Stroke Statistics, News, and Interesting Information
Can a Stroke be Treated?
Anyone who has a stroke needs immediate hospitalization, possibly including intensive care and life support. Unfortunately, there is no known cure for a stroke.
A stroke is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain. Blockage in blood flow or loss of blood causes the brain to lack oxygen and blood nutrients.
The brain requires a constant flow of blood to work properly. If the blood flow is disrupted, brain cells do not receive enough oxygen, resulting in cell death. The degree of damage that results from a stroke is dependent on where and how much blood flow to the brain is interrupted.
A stroke can be a sy
mptom of a serious condition such as brain cancer.A stroke is also called a cerebrovascular accident, cerebrovascular disease or CVA.
Categories of Strokes
There are two major categories of stroke: hemorrhagic and ischemic. Within the major categories are different kinds of strokes.
In ischemic strokes, there is a blockage of blood flow to the brain. About 80% of all strokes are ischemic. Ischemic strokes usually occur when a blood clot forms in a blood vessel in the brain or neck. Blood clots can also travel from other parts of the body, such as the heart, to the neck or brain and cause a stroke. A blood vessel that is extremely narrowed can also cause an ischemic stroke.
In hemorrhagic strokes a blood vessel in the brain is leaking or broken. These types of strokes accounts for approximately one out of five strokes. Hemorrhagic stroke is
associated with a higher death rate than ischemic stroke. Hemorrhage can occur from a weak or thinned out area on the artery wall that balloons out over time, and then ruptures.Kinds of Strokes
A stroke may also develop paralysis in one or both sides of the body.
How Does a Stroke Occur?
A stroke occurs when a blood vessel bringing oxygen and nutrients to the brain bursts or becomes blocked. Vessels can be blocked by blood clots or other particles. When blockage occurs, nerve cells in the part of the brain that is deprived of oxygen becomes dysfunctional. When the nerve cells become dysfunctional, the part of the body that is controlled by these cells is also unable to perform.
What Causes a Stroke?
Several different mechanisms may result in stroke: thrombus formation, embolus, and hemorrhage.
Thrombosis formation is an obstruction within an artery resulting from the gradual accumulation of plaque (atherosclerosis). If large enough, the obstructions may restrict or completely block blood flow through the artery. Blockage of arteries supplying the brain causes stroke if alternative routes are not available to deliver an adequate blood supply
Embolus is an obstruction of an artery due to material formed elsewhere in the body (such as the heart). The materials are usually generated in one part of the body and travels throughout the body until it becomes trapped in a blood vessel. The blood vessel then is unable to supply the brain with blood and nutrients.
Hemorrhage results from a rupture of a blood vessel located in the brain. Blood erupts at high pressure in the brain or in tissue surrounding the brain. Normal brain cells may be destroyed. The presence of blood often results in severe headache, lethargy, or coma.
Multiple Factors. Most strokes are associated with atherosclerosis, high blood pressure, oxygen damage or a combination of the three.
Medication. Some medications may increase the risk of developing a stroke. Vioxx, a medication used to treat arthritis was pulled off the market in September 2004 because it is linked to strokes and heart attacks.
What Does a Stroke Effect?
Stroke affects different people in different ways, depending on the type of stroke, the area of the brain affected and the extent of the brain injury. Brain injury from a stroke can affect the senses, motor activity, speech and the ability to understand speech, behavioral patterns, thought patterns, memory and emotions. Paralysis or weakness on one side of the body is common.
A stroke survivor may cry easily or experience sudden mood swings, often for no apparent reason. This is called emotional liability. Laughing uncontrollably also may occur but isn't as common as crying. Depression is common, as stroke survivors may feel less than "whole."
A stroke can also affect seeing, touching, moving and thinking, so a person's perception of everyday objects may be changed. Stroke survivors may not be able to recognize and understand familiar objects the way they did before. When vision is affected, objects may look closer or farther away than they really are, causing survivors to have spills at the table or collisions when walking.
Strokes may cause people to have problems understanding speech. They also may have trouble saying what they're thinking. This is called aphasia. Aphasia affects the ability to talk, listen, read and write. Aphasia is most common when a stroke weakens the body's right side.
A related problem is that a stroke can affect muscles used in talking (those in the tongue, palate and lips). Speech can be slowed, slurred or distorted, so stroke survivors can be hard to understand. This is called dysarthria and may require the help of a speech expert.
After a stroke, the individual often has difficulty thinking clearly. Planning and carrying out even simple activities may be hard. Stroke survivors may not know how to start a task, confuse the sequence of logical steps in tasks, or forget how to do tasks they've done many times before.
Signs of a Major Stroke
Some of the signs of major stroke are facial weakness, inability to talk, loss of bladder control, difficulty in breathing and swallowing, and paralysis or weakness, particularly on one side of the body.
Risks of developing a Stroke
Some of the most common risks of developing a stroke are:
A history of high blood pressure
heart disease
smoking
atherosclerosis
diabetes
migraine headaches
high levels of tryglycerides (a fatty substance in the blood)
use of birth control pills
Stroke Statistics, News, and Interesting Information
Can a Stroke be Treated?
Anyone who has a stroke needs immediate hospitalization, possibly including intensive care and life support. Unfortunately, there is no known cure for a stroke.
Human Brain
HUMAN BRAIN
What is the Brain?
The brain is the portion of the central nervous system in vertebrates (animals with bones) that lies within the skull. In humans, the brain weighs about 3 pounds. Differences in weight and size do not correlate with differences in mental ability.
The brain is the control center for movement, sleep, hunger, thirst, and virtually every other vital activity necessary to survive.
The brain is a pinkish-gray mass that is composed of about 10 billion nerve cells. The nerve cells are linked to each other and together are responsible for the control of all mental functions. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter.
The entire brain is enveloped in three protective sheets known as the meninges, continuations of the membranes that wrap the spinal cord. The two inner sheets enclose a shock-absorbing cushion of cerebrospinal fluid. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter.
The brain is divided into three major parts, the hindbrain (including the cerebellum and the brain stem), the midbrain, and the forebrain (including the diencephalon and the cerebrum).
The brain is a delicate organ that must be protected. When participating in activities such as skiing or snowboarding, wear a helmet to help reduce brain injuries. Also, try to avoid heat stroke because the brain can only function in a very narrow temperature range.
What is the brain's major function?
Each area of the brain has an associated function, although many functions may involve a number of different areas.
The cerebellum is the hind part of the brain. It is made up of gray, unmyelinated cells on the exterior and white, myelinated cells in the interior. The cerebellum coordinates muscular movements and, along with the midbrain, monitors posture. It is essential to the control of movement of the human body in space. The brain stem, which incorporates the medulla and the pons, monitors involuntary activities such as breathing and vomiting.
The thalamus, which forms the major part of the diencephalon, receives incoming sensory impulses and routes them to the appropriate higher centers. The hypothalamus, occupying the rest of the diencephalon, regulates heartbeat, body temperature, and fluid balance. Above the thalamus extends the corpus callosum, a neuron-rich membrane connecting the two hemispheres of the cerebrum.
The cerebrum occupies the topmost portion of the skull. It is by far the largest part of the brain. It makes up about 85% of the brain's weight. The cerebrum is split vertically into left and right hemispheres, it appears deeply fissured and grooved. Its upper surface, the cerebral cortex, contains most of the master controls of the body. In the cerebral cortex ultimate analysis of sensory data occurs, and motor impulses originate that initiate, reinforce, or inhibit the entire spectrum of muscle and gland activity. The left half of the cerebrum controls the right side of the body; the right half controls the left side. (This explains why if a stroke occurs in the left half of the brain, the right side of the body is affected)
Other important parts of the brain are the pituitary gland, the basal ganglia, and the reticular activating system (RAS). The pituitary participates in growth regulation. The basal ganglia, located just above the diencephalon in each cerebral hemisphere, handle coordination and habitual but acquired skills like chewing and playing the piano. The RAS forms a special system of nerve cells linking the medulla, pons, midbrain, and cerebral cortex. The RAS functions as a sentry. In a noisy crowd, for example, the RAS alerts a person when a friend speaks and enables that person to ignore other sounds.
Diseases and Conditions of the Brain
Stroke, meningitis, multiple sclerosis, coma, paralytic polio, Parkinson's disease, Leu Gering’s Disease, Cerebral Palsy, and migraine headaches are all diseases and conditions that affect the brain.
stroke- is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain.
Meningitis- is an inflammation of the meninges (membranes covering the brain).
Multiple sclerosis- affects transmission of electrical signals to nerve cells.
Coma- is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli.
Paralytic polio, the polio virus invades the central nervous system -- the spinal cord and the brain.
Parkinson's Disease- is a disorder of the brain characterized by shaking and difficulty with walking, movement, and coordination.
Cerebral palsy -is a group of disorders are caused by injuries to the brain that occur during fetal development or near the time of birth.
Migraine headache-is a recurrent, throbbing headache usually felt on one side of the head.
What is the Brain?
The brain is the portion of the central nervous system in vertebrates (animals with bones) that lies within the skull. In humans, the brain weighs about 3 pounds. Differences in weight and size do not correlate with differences in mental ability.
The brain is the control center for movement, sleep, hunger, thirst, and virtually every other vital activity necessary to survive.The brain is a pinkish-gray mass that is composed of about 10 billion nerve cells. The nerve cells are linked to each other and together are responsible for the control of all mental functions. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter.
The entire brain is enveloped in three protective sheets known as the meninges, continuations of the membranes that wrap the spinal cord. The two inner sheets enclose a shock-absorbing cushion of cerebrospinal fluid. Nerve fibers in the brain are covered in a near-white substance called myelin and form the white matter of the brain. Nerve cell bodies, which are not covered by myelin sheaths, form the gray matter.
The brain is divided into three major parts, the hindbrain (including the cerebellum and the brain stem), the midbrain, and the forebrain (including the diencephalon and the cerebrum).
The brain is a delicate organ that must be protected. When participating in activities such as skiing or snowboarding, wear a helmet to help reduce brain injuries. Also, try to avoid heat stroke because the brain can only function in a very narrow temperature range.
What is the brain's major function?
Each area of the brain has an associated function, although many functions may involve a number of different areas.
The cerebellum is the hind part of the brain. It is made up of gray, unmyelinated cells on the exterior and white, myelinated cells in the interior. The cerebellum coordinates muscular movements and, along with the midbrain, monitors posture. It is essential to the control of movement of the human body in space. The brain stem, which incorporates the medulla and the pons, monitors involuntary activities such as breathing and vomiting.
The thalamus, which forms the major part of the diencephalon, receives incoming sensory impulses and routes them to the appropriate higher centers. The hypothalamus, occupying the rest of the diencephalon, regulates heartbeat, body temperature, and fluid balance. Above the thalamus extends the corpus callosum, a neuron-rich membrane connecting the two hemispheres of the cerebrum.
The cerebrum occupies the topmost portion of the skull. It is by far the largest part of the brain. It makes up about 85% of the brain's weight. The cerebrum is split vertically into left and right hemispheres, it appears deeply fissured and grooved. Its upper surface, the cerebral cortex, contains most of the master controls of the body. In the cerebral cortex ultimate analysis of sensory data occurs, and motor impulses originate that initiate, reinforce, or inhibit the entire spectrum of muscle and gland activity. The left half of the cerebrum controls the right side of the body; the right half controls the left side. (This explains why if a stroke occurs in the left half of the brain, the right side of the body is affected)
Other important parts of the brain are the pituitary gland, the basal ganglia, and the reticular activating system (RAS). The pituitary participates in growth regulation. The basal ganglia, located just above the diencephalon in each cerebral hemisphere, handle coordination and habitual but acquired skills like chewing and playing the piano. The RAS forms a special system of nerve cells linking the medulla, pons, midbrain, and cerebral cortex. The RAS functions as a sentry. In a noisy crowd, for example, the RAS alerts a person when a friend speaks and enables that person to ignore other sounds.
Diseases and Conditions of the Brain
Stroke, meningitis, multiple sclerosis, coma, paralytic polio, Parkinson's disease, Leu Gering’s Disease, Cerebral Palsy, and migraine headaches are all diseases and conditions that affect the brain.
stroke- is damage to the brain due either to blockage in blood flow or to loss of blood from blood vessels in the brain.
Meningitis- is an inflammation of the meninges (membranes covering the brain).
Multiple sclerosis- affects transmission of electrical signals to nerve cells.
Coma- is an extended period of unconsciousness from which a person cannot be aroused even with the most painful stimuli.
Paralytic polio, the polio virus invades the central nervous system -- the spinal cord and the brain.
Parkinson's Disease- is a disorder of the brain characterized by shaking and difficulty with walking, movement, and coordination.
Cerebral palsy -is a group of disorders are caused by injuries to the brain that occur during fetal development or near the time of birth.
Migraine headache-is a recurrent, throbbing headache usually felt on one side of the head.
Human Disease
Human Disease
Human Disease, in medicine, any harmful change that interferes with the normal appearance, structure, or function of the body or any of its parts. Since time immemorial, disease has played a role in the history of societies. It has affected—and been affected by—economic conditions, wars, and natural disasters. Indeed, the impact of disease can be far greater than better-known calamities. An epidemic of influenza that swept the globe in 1918 killed from 20 million to 50 million people—two to five times more deaths than were caused by World War I (1914-1918). Within a few months, more than 500,000 Americans died of the 1918 influenza known as the Spanish flu.
Diseases have diverse causes, which can be classified into two broad groups: infectious and noninfectious. Infectious diseases can spread from one person to another and are caused by microscopic organisms that invade the body. Noninfectious diseases are not communicated from person to person and do not have, or are not known to involve, infectious agents. Some diseases, such as the common cold, are acute, coming on suddenly and lasting for no more than a few weeks. Other diseases, such as arthritis, are chronic, persisting for months or years, or recurring frequently.
Every disease has certain characteristic effects on the body. Some of these effects, called symptoms and signs, include fever, inflammation, pain, fatigue, dizziness, nausea, and rashes, and are readily apparent to the patient. These symptoms offer important clues that help physicians and other health-care professionals make a diagnosis. Many times, however, the symptoms point to several possible disorders. In those cases, doctors rely on medical tests, such as blood examinations and X rays, to confirm the diagnosis.
The course of a disease—that is, the path it follows from onset to end—can vary tremendously, depending largely on the individual and the treatment he or she receives. For example, otherwise healthy people usually recover quickly from a bout of pneumonia if given proper treatment, whereas pneumonia often proves fatal to people with a weakened immune system and to those who do not receive prompt, effective treatment. Some diseases run a different course depending on the patient’s age. Chicken pox, for instance, is usually mild in childhood but severe in adults. In the United States, only about 5 percent of chicken pox cases occur in people over the age of 20, but these cases account for 50 percent of all deaths from the disease.
Scientists, public health officials, and other members of the medical community work diligently to try to prevent disease epidemics. The battle is constant and is fought on many fronts. There have been many victories. Once-devastating diseases such as smallpox and diphtheria have been virtually eradicated, and many other diseases that once conferred automatic death sentences can now be either cured or controlled. At the same time, however, new killers have emerged. Acquired immunodeficiency syndrome (AIDS), Hantavirus pulmonary syndrome, and avian flu are among at least 30 diseases that have been identified by scientists since the early 1970s. Other growing challenges, particularly in the affluent societies of
industrialized nations, are so-called diseases of choice, such as alcohol abuse, drug abuse, or obesity, that result from addictive behavior, poor eating habits, or insufficient exercise.
complicating matters further are societal changes. Increased international travel accelerates the spread of both new and old diseases: A person infected with an unusual virus on one continent can arrive—with the virus—on another continent in a matter of hours. Ships, planes, and trucks can transport disease-carrying organisms just as easily. In 1985 tires imported into Texas from Asia carried larvae of the Asian tiger mosquito, which is a carrier of dengue fever and other tropical diseases. Within five years, Asian tiger mosquitoes were living in 17 states. Changing dietary habits and the availability in local supermarkets of foods from all parts of the world contribute to an increase in food-borne illnesses. Some researchers worry that growing populations and the resulting crowded living conditions will increase the risk
of epidemics.
Infectious disease
Infectious diseases are caused by microscopic organisms commonly called germs. Physicians refer to these disease-causing organisms as pathogens. Pathogens that infect humans include a wide variety of bacteria, viruses, fungi, protozoan, and parasitic worms. In addition, it has been theorized that some proteins called prisons may cause infectious diseases.
Pathogens
Bacteria are microscopic single-celled organisms at least 1 micron long. Most bacteria species are harmless to humans; indeed, many are beneficial. But some are pathogens, including those that cause cholera, diphtheria, leprosy, plague, pneumonia, strep throat, tetanus, tuberculosis, and typhoid fever.
Viruses are tens or hundreds of times smaller than bacteria. They are not cellular, but consist of a core of genetic material surrounded by a protective coat of protein. Viruses are able to survive and reproduce only in the living cells of a host. Once a virus invades a living cell, it directs the cell to make new virus particles. These new viruses are released into the surrounding tissues, and seek out new cells to infect. The roll call of human diseases caused by viruses includes mumps, measles, influenza, rabies, hepatitis, poliomyelitis, smallpox, AIDS, and certain types of cancer.
Fungi are a varied group of generally small organisms that get their food from living or dead organic matter. They germinate from reproductive cells called spores, which often have a thick, resistant outer coat that protects against unfavorable environmental conditions. This enables spores to survive for long periods of time, which adds to the difficulty of treating fungal infections. Some fungi are external parasites of humans, causing skin conditions such as ringworm, athlete's foot, and jock itch. Other fungi invade internal tissues; examples include yeast that infect the genital tract and several fungi species that cause a type of pneumonia.
Protozoan are single-celled, animal-like organisms that live in moist environments. Perhaps the most infamous pathogenic protozoans are species of the genus Plasmodium, which cause malaria, an infectious disease responsible for over ‚Q million deaths worldwide each year.
Spread of Infectious Disease
Some pathogens are spread from one person to another by direct contact. They leave the first person through body openings, mucous membranes, and skin wounds, and they enter the second person through similar channels. For example, the viruses that cause respiratory diseases such as influenza and the common cold are spread in moisture droplets when an infected person coughs or sneezes. A hand that was used to cover the mouth while coughing contains viruses that may be passed to doorknobs, so that the next person to touch the doorknob has a chance of picking up the infectious agent. The bacteria that cause some sexually transmitted infections, including gonorrhea and syphilis, are transmitted during sexual contact.
Other pathogens involve an intermediary carrier, such as an insect. The malarial parasite, for example, spends part of its life cycle in mosquitoes, then enters a person's bloodstream when the mosquito bites the person. Many pathogens are spread through contaminated food and water. Cholera bacteria, for example, are spread through food and water contaminated with the excrement of infected people.
New Infectious Diseases
In 1978 the United Nations adopted a resolution that set goals for eradicating infectious disease by the year 2000. This lofty goal proved impossible to achieve. The years since the resolution was adopted have seen the emergence of new killers and a rise in the incidence of such ancient scourges as malaria, yellow fever, and tuberculosis.
Among the diseases new to science are AIDS, Ebola hemorrhagic fever, Legionnaires’ disease, and Lyme disease. AIDS has been the most deadly of all the new diseases, but even it has not taken as high a toll as malaria, tuberculosis, and other diseases that have been around for centuries. Some newly identified disease-causing agents for diseases that have been recognized for a long time include Human T-lymphotropic virus I (HTLV-1), which can cause some cases of non-Hodgkin’s lymphoma, a type of cancer originating in the lymphatic system; and HTLV-2, which is associated with hairy-cell leukemia, a rare type of cancer of the blood.
In most cases, the reasons for the emergence of a new disease are unknown. One exception is Legionnaires’ disease. It is caused by a bacterium that was not identified until after an outbreak in 1976 at an American Legion convention in Philadelphia, Pennsylvania. Once identified, however, scientists were able to retrospectively identify earlier epidemics of the disease, and realized that each year the bacterium is responsible for thousands of cases of pneumonia. Environmental changes may be responsible for some new diseases. Scientists speculate that the viruses for some of the deadly hemorrhagic fevers that have surfaced in Africa, such as Ebola and Marburg disease, have long existed in certain wild animals. As people have encroached on wilderness areas they have come into contact with the infected animals, and the viruses have jumped from their traditional animal host to a new human host, with deadly consequences.
Human Disease, in medicine, any harmful change that interferes with the normal appearance, structure, or function of the body or any of its parts. Since time immemorial, disease has played a role in the history of societies. It has affected—and been affected by—economic conditions, wars, and natural disasters. Indeed, the impact of disease can be far greater than better-known calamities. An epidemic of influenza that swept the globe in 1918 killed from 20 million to 50 million people—two to five times more deaths than were caused by World War I (1914-1918). Within a few months, more than 500,000 Americans died of the 1918 influenza known as the Spanish flu.
Diseases have diverse causes, which can be classified into two broad groups: infectious and noninfectious. Infectious diseases can spread from one person to another and are caused by microscopic organisms that invade the body. Noninfectious diseases are not communicated from person to person and do not have, or are not known to involve, infectious agents. Some diseases, such as the common cold, are acute, coming on suddenly and lasting for no more than a few weeks. Other diseases, such as arthritis, are chronic, persisting for months or years, or recurring frequently.
Every disease has certain characteristic effects on the body. Some of these effects, called symptoms and signs, include fever, inflammation, pain, fatigue, dizziness, nausea, and rashes, and are readily apparent to the patient. These symptoms offer important clues that help physicians and other health-care professionals make a diagnosis. Many times, however, the symptoms point to several possible disorders. In those cases, doctors rely on medical tests, such as blood examinations and X rays, to confirm the diagnosis.
The course of a disease—that is, the path it follows from onset to end—can vary tremendously, depending largely on the individual and the treatment he or she receives. For example, otherwise healthy people usually recover quickly from a bout of pneumonia if given proper treatment, whereas pneumonia often proves fatal to people with a weakened immune system and to those who do not receive prompt, effective treatment. Some diseases run a different course depending on the patient’s age. Chicken pox, for instance, is usually mild in childhood but severe in adults. In the United States, only about 5 percent of chicken pox cases occur in people over the age of 20, but these cases account for 50 percent of all deaths from the disease.
Scientists, public health officials, and other members of the medical community work diligently to try to prevent disease epidemics. The battle is constant and is fought on many fronts. There have been many victories. Once-devastating diseases such as smallpox and diphtheria have been virtually eradicated, and many other diseases that once conferred automatic death sentences can now be either cured or controlled. At the same time, however, new killers have emerged. Acquired immunodeficiency syndrome (AIDS), Hantavirus pulmonary syndrome, and avian flu are among at least 30 diseases that have been identified by scientists since the early 1970s. Other growing challenges, particularly in the affluent societies of
industrialized nations, are so-called diseases of choice, such as alcohol abuse, drug abuse, or obesity, that result from addictive behavior, poor eating habits, or insufficient exercise.
complicating matters further are societal changes. Increased international travel accelerates the spread of both new and old diseases: A person infected with an unusual virus on one continent can arrive—with the virus—on another continent in a matter of hours. Ships, planes, and trucks can transport disease-carrying organisms just as easily. In 1985 tires imported into Texas from Asia carried larvae of the Asian tiger mosquito, which is a carrier of dengue fever and other tropical diseases. Within five years, Asian tiger mosquitoes were living in 17 states. Changing dietary habits and the availability in local supermarkets of foods from all parts of the world contribute to an increase in food-borne illnesses. Some researchers worry that growing populations and the resulting crowded living conditions will increase the risk
of epidemics.
Infectious disease
Infectious diseases are caused by microscopic organisms commonly called germs. Physicians refer to these disease-causing organisms as pathogens. Pathogens that infect humans include a wide variety of bacteria, viruses, fungi, protozoan, and parasitic worms. In addition, it has been theorized that some proteins called prisons may cause infectious diseases.
Pathogens
Bacteria are microscopic single-celled organisms at least 1 micron long. Most bacteria species are harmless to humans; indeed, many are beneficial. But some are pathogens, including those that cause cholera, diphtheria, leprosy, plague, pneumonia, strep throat, tetanus, tuberculosis, and typhoid fever.
Viruses are tens or hundreds of times smaller than bacteria. They are not cellular, but consist of a core of genetic material surrounded by a protective coat of protein. Viruses are able to survive and reproduce only in the living cells of a host. Once a virus invades a living cell, it directs the cell to make new virus particles. These new viruses are released into the surrounding tissues, and seek out new cells to infect. The roll call of human diseases caused by viruses includes mumps, measles, influenza, rabies, hepatitis, poliomyelitis, smallpox, AIDS, and certain types of cancer.
Fungi are a varied group of generally small organisms that get their food from living or dead organic matter. They germinate from reproductive cells called spores, which often have a thick, resistant outer coat that protects against unfavorable environmental conditions. This enables spores to survive for long periods of time, which adds to the difficulty of treating fungal infections. Some fungi are external parasites of humans, causing skin conditions such as ringworm, athlete's foot, and jock itch. Other fungi invade internal tissues; examples include yeast that infect the genital tract and several fungi species that cause a type of pneumonia.
Protozoan are single-celled, animal-like organisms that live in moist environments. Perhaps the most infamous pathogenic protozoans are species of the genus Plasmodium, which cause malaria, an infectious disease responsible for over ‚Q million deaths worldwide each year.
Spread of Infectious Disease
Some pathogens are spread from one person to another by direct contact. They leave the first person through body openings, mucous membranes, and skin wounds, and they enter the second person through similar channels. For example, the viruses that cause respiratory diseases such as influenza and the common cold are spread in moisture droplets when an infected person coughs or sneezes. A hand that was used to cover the mouth while coughing contains viruses that may be passed to doorknobs, so that the next person to touch the doorknob has a chance of picking up the infectious agent. The bacteria that cause some sexually transmitted infections, including gonorrhea and syphilis, are transmitted during sexual contact.
Other pathogens involve an intermediary carrier, such as an insect. The malarial parasite, for example, spends part of its life cycle in mosquitoes, then enters a person's bloodstream when the mosquito bites the person. Many pathogens are spread through contaminated food and water. Cholera bacteria, for example, are spread through food and water contaminated with the excrement of infected people.
New Infectious Diseases
In 1978 the United Nations adopted a resolution that set goals for eradicating infectious disease by the year 2000. This lofty goal proved impossible to achieve. The years since the resolution was adopted have seen the emergence of new killers and a rise in the incidence of such ancient scourges as malaria, yellow fever, and tuberculosis.
Among the diseases new to science are AIDS, Ebola hemorrhagic fever, Legionnaires’ disease, and Lyme disease. AIDS has been the most deadly of all the new diseases, but even it has not taken as high a toll as malaria, tuberculosis, and other diseases that have been around for centuries. Some newly identified disease-causing agents for diseases that have been recognized for a long time include Human T-lymphotropic virus I (HTLV-1), which can cause some cases of non-Hodgkin’s lymphoma, a type of cancer originating in the lymphatic system; and HTLV-2, which is associated with hairy-cell leukemia, a rare type of cancer of the blood.
In most cases, the reasons for the emergence of a new disease are unknown. One exception is Legionnaires’ disease. It is caused by a bacterium that was not identified until after an outbreak in 1976 at an American Legion convention in Philadelphia, Pennsylvania. Once identified, however, scientists were able to retrospectively identify earlier epidemics of the disease, and realized that each year the bacterium is responsible for thousands of cases of pneumonia. Environmental changes may be responsible for some new diseases. Scientists speculate that the viruses for some of the deadly hemorrhagic fevers that have surfaced in Africa, such as Ebola and Marburg disease, have long existed in certain wild animals. As people have encroached on wilderness areas they have come into contact with the infected animals, and the viruses have jumped from their traditional animal host to a new human host, with deadly consequences.
Muscles
Muscles and Movement
Muscles that move the body are called skeletal muscles. There are about 640 of them and they give the body its shape. Skeletal muscles are attached to bones. They work by contracting, or getting shorter. When a muscle contracts, it pulls the bone it is attached to. Skeletal muscles produce all movements, including running and chewing.
Different Shapes and sizes
Muscles vary in size and shape and are found all over the body. The longest are in the thigh. The biggest are the buttock muscles used in climbing and running. The tiniest muscles are inside the ear.
Tendons
Muscles are joined to bones by tough cords called tendons. When a muscle contracts, it pulls the tendon, which then pulls the bone. The Achilles tendon is a large tendon that joins the calf muscle to the heel bone.
Making a Face
There are more than 40 small muscles in the face and neck. When they contract, they pull on the skin of the face to produce a wide range of facial expressions. These expressions, which include frowning and smiling, show whether a person is feeling sad, happy, angry, or frightened.
Muscle Pairs
Muscles usually work in pairs, with each muscle causing opposite movements. These are called antagonistic muscles. In the arm, the biceps muscle contracts and shortens to bend
The arm at the elbow. The triceps contracts to straighten the arm.
AMAZING FACTS
Muscles make up nearly half the body’s total weight.
Whether a person is asleep or awake, muscles move the eyes 100,000 times every day.
Muscles that move the body are called skeletal muscles. There are about 640 of them and they give the body its shape. Skeletal muscles are attached to bones. They work by contracting, or getting shorter. When a muscle contracts, it pulls the bone it is attached to. Skeletal muscles produce all movements, including running and chewing.
Different Shapes and sizes
Muscles vary in size and shape and are found all over the body. The longest are in the thigh. The biggest are the buttock muscles used in climbing and running. The tiniest muscles are inside the ear.
Tendons
Muscles are joined to bones by tough cords called tendons. When a muscle contracts, it pulls the tendon, which then pulls the bone. The Achilles tendon is a large tendon that joins the calf muscle to the heel bone.
Making a Face
There are more than 40 small muscles in the face and neck. When they contract, they pull on the skin of the face to produce a wide range of facial expressions. These expressions, which include frowning and smiling, show whether a person is feeling sad, happy, angry, or frightened.
Muscle Pairs
Muscles usually work in pairs, with each muscle causing opposite movements. These are called antagonistic muscles. In the arm, the biceps muscle contracts and shortens to bend
The arm at the elbow. The triceps contracts to straighten the arm.
AMAZING FACTS
Muscles make up nearly half the body’s total weight.
Whether a person is asleep or awake, muscles move the eyes 100,000 times every day.
Tuesday, October 20, 2009
Human body
Human Body
Introducing
Built on a framework of bones, which are stronger than steel, is the most complicated of all machines –your body.
It can breathe, smell, and taste. It can feel, talk, and walk. It eats, drinks, and thinks. It can even mend itself when it is damaged.
The brain is in charge, controlling all your body’s systems. These work together throughout your life. As you grow up, your body will go through lots of changes, but if you look after your amazing body machine, it should last you for a long time.
Body Systems
The Human body is made up of different systems, such as the nervous system and skeleton. While each system has its own special job, it works with other systems to keep the body alive and in perfect working order. Each system is a collection of organs. Each organ, such as the brain or stomach, has its own special job.
MUSCULAR SYSTEM
All the body’s movements, such as running and jumping, are produced by muscles. Most muscles work by pulling the bones of the skeleton to which they are attached
AMAZING FACTS
Laid end to end , your blood vessels would reach a quarter of the way from the earth to the moon.
CIRCULATORY SYSTEM
The heart, blood, and a network of blood vessels make up the circulatory system. Pumped along by the heart, blood delivers oxygen and nutrients to the body and takes away waste products.
NERVOUS SYSTEM
All The body’s activities, including walking, seeing, thinking, and speaking, are controlled by the nervous system. The brain is in charge of the nervous system. It receives messages and sends out instructions along the spinal cord and the network of nerves.
RESPIRATORY SYSTEM
The body needs energy to stay alive. Energy is released from food by combining it with oxygen. The respiratory system supplies the body with oxygen. When a breath is taken in through the nose or mouth, air containing oxygen is carried along the windpipe and into the lungs
DIGESTIVE SYSTEM
Everything you eat and drink is broken down by the digestive system into simple substances called nutrients. These are carried by the blood to all parts of the body and used to give you energy and make you grow.
The Skeleton
The adult skeleton is made up of 206 bones. It provides a strong, but light, framework that supports the body. Where bones meet, at joints, they move when pulled b
y muscles. This gives the body a wide rang of movements. The skeleton also protects important parts of the body. The ribs shield the lungs and heart, and the skull protects the brain.
LITTLE AND LARGE
Bones come in many shapes and sizes. The strong, long bones in the legs enable the body to run and jump. The smaller bones in the hands help with tasks such as picking up and gripping things.
INSIDE A BONE
The outer layer of a bone is made of a very hard material called compact bone. Inside is lighter spongy bone. Together they make the bone very strong but light. The spaces inside spongy bone contain red bone marrow. This makes millions of new blood cells every minute.
AMAZING FACTS
The leg has only 4 bones: the foot has 26.
Living bone is six times stronger than a steel bar of the same weight.
JOINTS
Bones meet at joints. A few joints are stationary, but most are movable. An oily liquid, called synovial fluid, lies between the bones in a joint. This keeps the joint moving smoothly. Strong cords called ligaments hold the joint together.
STRONG SUPPORT
The backbone in babies is made up of 33 bones, called vertebrae. In adults, some join together so there are 24 vertebrae. The delicate spinal cord, which links the brain and nerves, lies protected inside the backbone
Introducing
Built on a framework of bones, which are stronger than steel, is the most complicated of all machines –your body.
It can breathe, smell, and taste. It can feel, talk, and walk. It eats, drinks, and thinks. It can even mend itself when it is damaged.
The brain is in charge, controlling all your body’s systems. These work together throughout your life. As you grow up, your body will go through lots of changes, but if you look after your amazing body machine, it should last you for a long time.
Body Systems
The Human body is made up of different systems, such as the nervous system and skeleton. While each system has its own special job, it works with other systems to keep the body alive and in perfect working order. Each system is a collection of organs. Each organ, such as the brain or stomach, has its own special job.
MUSCULAR SYSTEM
All the body’s movements, such as running and jumping, are produced by muscles. Most muscles work by pulling the bones of the skeleton to which they are attached
AMAZING FACTS
Laid end to end , your blood vessels would reach a quarter of the way from the earth to the moon.
CIRCULATORY SYSTEM
The heart, blood, and a network of blood vessels make up the circulatory system. Pumped along by the heart, blood delivers oxygen and nutrients to the body and takes away waste products.
NERVOUS SYSTEM
All The body’s activities, including walking, seeing, thinking, and speaking, are controlled by the nervous system. The brain is in charge of the nervous system. It receives messages and sends out instructions along the spinal cord and the network of nerves.
RESPIRATORY SYSTEM
The body needs energy to stay alive. Energy is released from food by combining it with oxygen. The respiratory system supplies the body with oxygen. When a breath is taken in through the nose or mouth, air containing oxygen is carried along the windpipe and into the lungs
DIGESTIVE SYSTEM
Everything you eat and drink is broken down by the digestive system into simple substances called nutrients. These are carried by the blood to all parts of the body and used to give you energy and make you grow.
The Skeleton
The adult skeleton is made up of 206 bones. It provides a strong, but light, framework that supports the body. Where bones meet, at joints, they move when pulled b
y muscles. This gives the body a wide rang of movements. The skeleton also protects important parts of the body. The ribs shield the lungs and heart, and the skull protects the brain.LITTLE AND LARGE
Bones come in many shapes and sizes. The strong, long bones in the legs enable the body to run and jump. The smaller bones in the hands help with tasks such as picking up and gripping things.
INSIDE A BONE
The outer layer of a bone is made of a very hard material called compact bone. Inside is lighter spongy bone. Together they make the bone very strong but light. The spaces inside spongy bone contain red bone marrow. This makes millions of new blood cells every minute.
AMAZING FACTS
The leg has only 4 bones: the foot has 26.
Living bone is six times stronger than a steel bar of the same weight.
JOINTS
Bones meet at joints. A few joints are stationary, but most are movable. An oily liquid, called synovial fluid, lies between the bones in a joint. This keeps the joint moving smoothly. Strong cords called ligaments hold the joint together.
STRONG SUPPORT
The backbone in babies is made up of 33 bones, called vertebrae. In adults, some join together so there are 24 vertebrae. The delicate spinal cord, which links the brain and nerves, lies protected inside the backbone
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