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All living things reproduce. Reproduction — the process by which organisms make more organisms like themselves — is one of the things that sets living things apart from nonliving things. But even though the reproductive system is essential to keeping a species alive, unlike other body systems it's not essential to keeping an individual alive.
In the human reproductive process, two kinds of sex cells, or gametes, are involved. The male gamete, or sperm, and the female gamete, the egg or ovum, meet in the female's reproductive system to create a new individual. Both the male and female reproductive systems are essential for reproduction.
Humans, like other organisms, pass certain characteristics of themselves to the next generation through their genes, the special carriers of human traits. The genes parents pass along to their offspring are what make kids similar to others in their family, but they're also what make each child unique. These genes come from the father's sperm and the mother's egg, which are produced by the male and female reproductive systems.
Understanding the male reproductive system, what it does, and the problems that can affect it can help you better understand your son's reproductive health.
About the Male Reproductive System
Most species have two sexes: male and female. Each sex has its own unique reproductive system. They are different in shape and structure, but both are specifically designed to produce, nourish, and transport either the egg or sperm.
Unlike the female, whose sex organs are located entirely within the pelvis, the male has reproductive organs, or genitals, that are both inside and outside the pelvis. The male genitals include:
•the testicles
•the duct system, which is made up of the epididymis and the vas deferens
•the accessory glands, which include the seminal vesicles and prostate gland
•the penis
In a guy who has reached sexual maturity, the two testicles, or testes, produce and store millions of tiny sperm cells. The testicles are oval-shaped and grow to be about 2 inches (5 centimeters) in length and 1 inch (3 centimeters) in diameter. The testicles are also part of the endocrine system because they produce hormones, including testosterone. Testosterone is a major part of puberty in boys, and as a guy makes his way through puberty, his testicles produce more and more of it. Testosterone is the hormone that causes boys to develop deeper voices, bigger muscles, and body and facial hair, and it also stimulates the production of sperm.
Alongside the testicles are the epididymis and the vas deferens, which make up the duct system of the male reproductive organs. The vas deferens is a muscular tube that passes upward alongside the testicles and transports the sperm-containing fluid called semen. The epididymis is a set of coiled tubes (one for each testicle) that connects to the vas deferens.
The epididymis and the testicles hang in a pouch-like structure outside the pelvis called the scrotum. This bag of skin helps to regulate the temperature of testicles, which need to be kept cooler than body temperature to produce sperm. The scrotum changes size to maintain the right temperature. When the body is cold, the scrotum shrinks and becomes tighter to hold in body heat. When it's warm, the scrotum becomes larger and more floppy to get rid of extra heat. This happens without a guy ever having to think about it. The brain and the nervous system give the scrotum the cue to change size.
The accessory glands, including the seminal vesicles and the prostate gland, provide fluids that lubricate the duct system and nourish the sperm. The seminal vesicles are sac-like structures attached to the vas deferens to the side of the bladder. The prostate gland, which produces some of the parts of semen, surrounds the ejaculatory ducts at the base of the urethra, just below the bladder. The urethra is the channel that carries the semen to the outside of the body through the penis. The urethra is also part of the urinary system because it is also the channel through which urine passes as it leaves the bladder and exits the body.
The penis is actually made up of two parts: the shaft and the glans. The shaft is the main part of the penis and the glans is the tip (sometimes called the head). At the end of the glans is a small slit or opening, which is where semen and urine exit the body through the urethra. The inside of the penis is made of a spongy tissue that can expand and contract.
All boys are born with a foreskin, a fold of skin at the end of the penis covering the glans. Some boys are circumcised, which means that a doctor or clergy member cuts away the foreskin. Circumcision is usually performed during a baby boy's first few days of life. Although circumcision is not medically necessary, parents who choose to have their children circumcised often do so based on religious beliefs, concerns about hygiene, or cultural or social reasons. Boys who have circumcised penises and those who don't are no different: All penises work and feel the same, regardless of whether the foreskin has been removed.
What the Male Reproductive System Does
The male sex organs work together to produce and release semen into the reproductive system of the female during sexual intercourse. The male reproductive system also produces sex hormones, which help a boy develop into a sexually mature man during puberty.
When a baby boy is born, he has all the parts of his reproductive system in place, but it isn't until puberty that he is able to reproduce. When puberty begins, usually between the ages of 10 and 14, the pituitary gland —which is located near the brain — secretes hormones that stimulate the testicles to produce testosterone. The production of testosterone brings about many physical changes. Although the timing of these changes is different for every guy, the stages of puberty generally follow a set sequence.
•During the first stage of male puberty, the scrotum and testes grow larger.
•Next, the penis becomes longer, and the seminal vesicles and prostate gland grow.
•Hair begins to appear in the pubic area and later it grows on the face and underarms. During this time, a male's voice also deepens.
•Boys also undergo a growth spurt during puberty as they reach their adult height and weight.
Sperm
A male who has reached puberty will produce millions of sperm cells every day. Each sperm is extremely small: only 1/600 of an inch (0.05 millimeters long). Sperm develop in the testicles within a system of tiny tubes called the seminiferous tubules. At birth, these tubules contain simple round cells, but during puberty, testosterone and other hormones cause these cells to transform into sperm cells. The cells divide and change until they have a head and short tail, like tadpoles. The head contains genetic material (genes). The sperm use their tails to push themselves into the epididymis, where they complete their development. It takes sperm about 4 to 6 weeks to travel through the epididymis.
The sperm then move to the vas deferens, or sperm duct. The seminal vesicles and prostate gland produce a whitish fluid called seminal fluid, which mixes with sperm to form semen when a male is sexually stimulated. The penis, which usually hangs limp, becomes hard when a male is sexually excited. Tissues in the penis fill with blood and it becomes stiff and erect (an erection). The rigidity of the erect penis makes it easier to insert into the female's vagina during sexual intercourse. When the erect penis is stimulated, muscles around the reproductive organs contract and force the semen through the duct system and urethra. Semen is pushed out of the male's body through his urethra — this process is called ejaculation. Each time a guy ejaculates, it can contain up to 500 million sperm.
When the male ejaculates during intercourse, semen is deposited into the female's vagina. From the vagina the sperm make their way up through the cervix and move through the uterus with help from uterine contractions. If a mature egg is in one of the female's fallopian tubes, a single sperm may penetrate it, and fertilization, or conception, occurs.
This fertilized egg is now called a zygote and contains 46 chromosomes — half from the egg and half from the sperm. The genetic material from the male and female has combined so that a new individual can be created. The zygote divides again and again as it grows in the female's uterus, maturing over the course of the pregnancy into an embryo, a fetus, and finally a newborn baby.
Things That Can Go Wrong With the Male Reproductive System
Boys may sometimes experience reproductive system problems, including:
Disorders of the Scrotum, Testicles, or Epididymis
Conditions affecting the scrotal contents may involve the testicles, epididymis, or the scrotum itself.
•Testicular trauma. Even a mild injury to the testicles can cause severe pain, bruising, or swelling. Most testicular injuries occur when the testicles are struck, hit, kicked, or crushed, usually during sports or due to other trauma. Testicular torsion, when one of the testicles twists around, cutting off its blood supply, is also a problem that some teen males experience, although it's not common. Surgery is needed to untwist the cord and save the testicle.
•Varicocele. This is a varicose vein (an abnormally swollen vein) in the network of veins that run from the testicles. Varicoceles commonly develop while a boy is going through puberty. A varicocele is usually not harmful, although it can damage the testicle or decrease sperm production. Take your son to see his doctor if he is concerned about changes in his testicles.
•Testicular cancer. This is one of the most common cancers in men younger than 40. It occurs when cells in the testicle divide abnormally and form a tumor. Testicular cancer can spread to other parts of the body, but if it's detected early, the cure rate is excellent. Teen boys should be encouraged to learn to perform testicular self-examinations.
•Epididymitis is inflammation of the epididymis, the coiled tubes that connect the testes with the vas deferens. It is usually caused by an infection, such as the sexually transmitted disease chlamydia, and results in pain and swelling next to one of the testicles.
•Hydrocele. A hydrocele occurs when fluid collects in the membranes surrounding the testes. Hydroceles may cause swelling in the scrotum around the testicle but are generally painless. In some cases, surgery may be needed to correct the condition.
•Inguinal hernia. When a portion of the intestines pushes through an abnormal opening or weakening of the abdominal wall and into the groin or scrotum, it is known as an inguinal hernia. The hernia may look like a bulge or swelling in the groin area. It can be corrected with surgery.
Disorders of the Penis
Disorders affecting the penis include:
•Inflammation of the penis. Symptoms of penile inflammation include redness, itching, swelling, and pain. Balanitis occurs when the glans (the head of the penis) becomes inflamed. Posthitis is foreskin inflammation, which is usually due to a yeast or bacterial infection.
•Hypospadias. This is a disorder in which the urethra opens on the underside of the penis, not at the tip.
•Phimosis. This is a tightness of the foreskin of the penis and is common in newborns and young children. It usually resolves itself without treatment. If it interferes with urination, circumcision (removal of the foreskin) may be recommended.
•Paraphimosis. This may develop when the foreskin of a boy's uncircumcised penis is retracted (pulled down to expose the glans) and becomes trapped so it can't be returned to the unretracted position. As a result, blood flow to the head of the penis may be impaired, and your son may experience pain and swelling. A doctor may use lubricant to make a small incision so the foreskin can be pulled forward. If that doesn't work, circumcision may be recommended.
•Ambiguous genitalia. This occurs when a child is born with genitals that aren't clearly male or female. In most boys born with this disorder, the penis may be very small or nonexistent, but testicular tissue is present. In a small number of cases, the child may have both testicular and ovarian tissue.
•Micropenis. This is a disorder in which the penis, although normally formed, is well below the average size, as determined by standard measurements.
If your son has symptoms of a problem with his reproductive system or he has questions about growth and sexual development, talk with your doctor — many problems with the male reproductive system can be treated.
"I pray that this article empowers you to Get A L.I.F.E."
Saturday, June 25, 2011
Saturday, June 18, 2011
Lungs and Respiratory System
Breathing is so vital to life that it happens automatically. Each day, you breathe about 20,000 times, and by the time you're 70 years old, you'll have taken at least 600 million breaths.
All of this breathing couldn't happen without the respiratory system, which includes the nose, throat, voice box, windpipe, and lungs.
At the top of the respiratory system, the nostrils (also called nares) act as the air intake, bringing air into the nose, where it's warmed and humidified. Tiny hairs called cilia protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.
Air can also be taken in through the mouth. These two openings of the airway (the nasal cavity and the mouth) meet at the pharynx, or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air. At the bottom of the pharynx, this pathway divides in two, one for food (the esophagus, which leads to the stomach) and the other for air. The epiglottis, a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs.
The larynx, or voice box, is the uppermost part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds.
The trachea, or windpipe, extends downward from the base of the larynx. It lies partly in the neck and partly in the chest cavity. The walls of the trachea are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.
Trachea and Bronchi
At its bottom end, the trachea divides into left and right air tubes called bronchi, which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each lung houses about 300-400 million alveoli.
The lungs also contain elastic tissues that allow them to inflate and deflate without losing shape and are encased by a thin lining called the pleura. This network of alveoli, bronchioles, and bronchi is known as the bronchial tree.
The chest cavity, or thorax, is the airtight box that houses the bronchial tree, lungs, heart, and other structures. The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom is formed by a large muscle called the diaphragm. The chest walls form a protective cage around the lungs and other contents of the chest cavity.
Separating the chest from the abdomen, the diaphragm plays a lead role in breathing. It moves downward when we breathe in, enlarging the chest cavity and pulling air in through the nose or mouth. When we breathe out, the diaphragm moves upward, forcing the chest cavity to get smaller and pushing the gases in the lungs up and out of the nose and mouth.
What the Lungs and Respiratory System Do
The air we breathe is made up of several gases. Oxygen is the most important for keeping us alive because body cells need it for energy and growth. Without oxygen, the body's cells would die.
Carbon dioxide is the waste gas produced when carbon is combined with oxygen as part of the energy-making processes of the body. The lungs and respiratory system allow oxygen in the air to be taken into the body, while also enabling the body to get rid of carbon dioxide in the air breathed out.
Respiration
Respiration is the set of events that results in the exchange of oxygen from the environment and carbon dioxide from the body's cells. The process of taking air into the lungs is inspiration, or inhalation, and the process of breathing it out is expiration, or exhalation.
Air is inhaled through the mouth or through the nose. Cilia lining the nose and other parts of the upper respiratory tract move back and forth, pushing foreign matter that comes in with air (like dust) either toward the nostrils to be expelled or toward the pharynx. The pharynx passes the foreign matter along to the stomach to eventually be eliminated by the body. As air is inhaled, the mucous membranes of the nose and mouth warm and humidify the air before it enters the lungs.
When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward. In this way, the volume of the chest cavity is increased. Air pressure in the chest cavity and lungs is reduced, and because gas flows from high pressure to low, air from the environment flows through the nose or mouth into the lungs.
In exhalation, the diaphragm moves upward and the chest wall muscles relax, causing the chest cavity to contract. Air pressure in the lungs rises, so air flows from the lungs and up and out of respiratory system through the nose or mouth.
Every few seconds, with each inhalation, air fills a large portion of the millions of alveoli. In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood then flows back to the heart, which pumps it through the arteries to oxygen-hungry tissues throughout the body.
In the tiny capillaries of the body tissues, oxygen is freed from the hemoglobin and moves into the cells. Carbon dioxide, which is produced during the process of diffusion, moves out of these cells into the capillaries, where most of it is dissolved in the plasma of the blood. Blood rich in carbon dioxide then returns to the heart via the veins. From the heart, this blood is pumped to the lungs, where carbon dioxide passes into the alveoli to be exhaled.
Problems of the Lungs and Respiratory System
The respiratory system is susceptible to a number of diseases, and the lungs are prone to a wide range of disorders caused by pollutants in the air.
The most common problems of the respiratory system are:
Asthma. More than 20 million people in the United States have asthma, and it's the #1 reason that kids chronically miss school. Asthma is a chronic inflammatory lung disease that causes airways to tighten and narrow. Often triggered by irritants in the air such as cigarette smoke, asthma flares involve contraction of the muscles and swelling of the lining of the tiny airways. The resulting narrowing of the airways prevents air from flowing properly, causing wheezing and difficulty breathing, sometimes to the point of being life-threatening. Management of asthma starts with an asthma management plan, which usually involves avoiding asthma triggers and sometimes taking medications.
Bronchiolitis. Not to be confused with bronchitis, bronchiolitis is an inflammation of the bronchioles, the smallest branches of the bronchial tree. Bronchiolitis affects mostly infants and young children, and can cause wheezing and serious difficulty breathing. It's usually caused by specific viruses in the wintertime, including respiratory syncytial virus (RSV).
Chronic obstructive pulmonary disease (COPD). COPD is a term that describes two lung diseases — emphysema and chronic bronchitis:
•Long-term smoking often causes emphysema, and although it seldom affects kids and teens, it can have its roots in the teen and childhood years. Talking to your kids about smoking is a key part of preventing smoking-related diseases. In emphysema, the lungs produce an excessive amount of mucus and the alveoli become damaged. It becomes difficult to breathe and get enough oxygen into the blood.
•In bronchitis, a common disease of adults and teens, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person develops a bad cough to get rid of the mucus. Cigarette smoking is a major cause of chronic bronchitis in teens.
Other Conditions
Common cold. Caused by over 200 different viruses that cause inflammation in the upper respiratory tract, the common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat.
Cough. A cough is a symptom of an illness, not an illness itself. There are many different types of cough and many different causes, ranging from not-so-serious to life-threatening. Some of the more common causes affecting kids are the common cold, asthma, sinusitis, seasonal allergies, croup, and pneumonia. Among the most serious causes of cough are tuberculosis (TB) and whooping cough (pertussis).
Cystic fibrosis (CF). Affecting more than 30,000 kids and young adults in the United States, cystic fibrosis is the most common inherited disease affecting the lungs. Affecting primarily the respiratory and digestive systems, CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more vulnerable to bacterial infections.
Lung cancer. Caused by an abnormal growth of cells in the lungs, lung cancer is a leading cause of death in the United States and is usually caused by smoking cigarettes. It starts in the lining of the bronchi and takes a long time to develop. Symptoms include a persistent cough that may bring up blood, chest pain, hoarseness, and shortness of breath. Radon gas exposure (radon is a gas that occurs in soil and rocks) may also be a cause of lung cancer. Radon is more likely to occur in certain parts of the United States. You can check your home's radon level by purchasing a radon kit at your local home supply or hardware store.
Pneumonia. This inflammation of the lungs usually occurs because of bacterial or viral infection. Pneumonia causes fever and inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood. Common causes of pneumonia are influenza and infection with the bacterium Streptococcus pneumoniae.
Pulmonary Hypertension
This condition occurs when the blood pressure in the arteries of the lungs is abnormally high, which means the heart has to work harder to pump blood against the high pressure. Pulmonary hypertension may occur in children because of a heart defect present at birth or because of a health condition such as HIV infection.
Respiratory Diseases of Newborns
Several respiratory conditions can affect a newborn baby just starting to breathe for the first time. Premature babies are at increased risk for conditions such as:
•Respiratory distress syndrome of the newborn. Babies born prematurely may not have enough surfactant in the lungs. Surfactant helps to keep the baby's alveoli open; without surfactant, the lungs collapse and the baby is unable to breathe.
•Apnea of prematurity (AOP). Apnea is a medical term that means someone has stopped breathing. Apnea of prematurity (AOP) is a condition in which premature infants stop breathing for 15 to 20 seconds during sleep. Apnea of prematurity generally occurs after 2 days of life and up to a week of life. The lower the infant's weight and level of prematurity at birth, the more likely the baby is to have AOP spells.
•Bronchopulmonary dysplasia (BPD). BDP involves abnormal development of lung tissue. Sometimes called chronic lung disease or CLD, it's a disease in infants characterized by inflammation and scarring in the lungs. It develops most often in premature babies who are born with underdeveloped lungs.
•Meconium aspiration. Meconium aspiration occurs when a newborn inhales (aspirates) a mixture of meconium (baby's first feces, ordinarily passed after birth) and amniotic fluid during labor and delivery. The inhaled meconium can cause a partial or complete blockage of the baby's airways.
Additional Conditions
•Persistent pulmonary hypertension of the newborn (PPHN). In the uterus, a baby's circulation bypasses the lungs. Normally, when a baby is born and begins to breathe air, his or her body quickly adapts and begins the process of respiration. PPHN occurs when a baby's body doesn't make the normal transition from fetal circulation to newborn circulation. This condition can cause symptoms such as rapid breathing, rapid heart rate, respiratory distress, and cyanosis (blue-tinged skin).
•Transient tachypnea of the newborn (TTN). Rapid breathing in a full-term newborn (more than 60 breaths a minute) is called transient tachypnea.
Although some respiratory diseases can't be prevented, many chronic lung and respiratory illnesses can be prevented by avoiding smoking, staying away from pollutants and irritants, washing hands often to avoid infection, and getting regular medical checkups.
"I pray that this article empowers you to Get A L.I.F.E."
All of this breathing couldn't happen without the respiratory system, which includes the nose, throat, voice box, windpipe, and lungs.
At the top of the respiratory system, the nostrils (also called nares) act as the air intake, bringing air into the nose, where it's warmed and humidified. Tiny hairs called cilia protect the nasal passageways and other parts of the respiratory tract, filtering out dust and other particles that enter the nose through the breathed air.
Air can also be taken in through the mouth. These two openings of the airway (the nasal cavity and the mouth) meet at the pharynx, or throat, at the back of the nose and mouth. The pharynx is part of the digestive system as well as the respiratory system because it carries both food and air. At the bottom of the pharynx, this pathway divides in two, one for food (the esophagus, which leads to the stomach) and the other for air. The epiglottis, a small flap of tissue, covers the air-only passage when we swallow, keeping food and liquid from going into the lungs.
The larynx, or voice box, is the uppermost part of the air-only pipe. This short tube contains a pair of vocal cords, which vibrate to make sounds.
The trachea, or windpipe, extends downward from the base of the larynx. It lies partly in the neck and partly in the chest cavity. The walls of the trachea are strengthened by stiff rings of cartilage to keep it open. The trachea is also lined with cilia, which sweep fluids and foreign particles out of the airway so that they stay out of the lungs.
Trachea and Bronchi
At its bottom end, the trachea divides into left and right air tubes called bronchi, which connect to the lungs. Within the lungs, the bronchi branch into smaller bronchi and even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli, where the exchange of oxygen and carbon dioxide actually takes place. Each lung houses about 300-400 million alveoli.
The lungs also contain elastic tissues that allow them to inflate and deflate without losing shape and are encased by a thin lining called the pleura. This network of alveoli, bronchioles, and bronchi is known as the bronchial tree.
The chest cavity, or thorax, is the airtight box that houses the bronchial tree, lungs, heart, and other structures. The top and sides of the thorax are formed by the ribs and attached muscles, and the bottom is formed by a large muscle called the diaphragm. The chest walls form a protective cage around the lungs and other contents of the chest cavity.
Separating the chest from the abdomen, the diaphragm plays a lead role in breathing. It moves downward when we breathe in, enlarging the chest cavity and pulling air in through the nose or mouth. When we breathe out, the diaphragm moves upward, forcing the chest cavity to get smaller and pushing the gases in the lungs up and out of the nose and mouth.
What the Lungs and Respiratory System Do
The air we breathe is made up of several gases. Oxygen is the most important for keeping us alive because body cells need it for energy and growth. Without oxygen, the body's cells would die.
Carbon dioxide is the waste gas produced when carbon is combined with oxygen as part of the energy-making processes of the body. The lungs and respiratory system allow oxygen in the air to be taken into the body, while also enabling the body to get rid of carbon dioxide in the air breathed out.
Respiration
Respiration is the set of events that results in the exchange of oxygen from the environment and carbon dioxide from the body's cells. The process of taking air into the lungs is inspiration, or inhalation, and the process of breathing it out is expiration, or exhalation.
Air is inhaled through the mouth or through the nose. Cilia lining the nose and other parts of the upper respiratory tract move back and forth, pushing foreign matter that comes in with air (like dust) either toward the nostrils to be expelled or toward the pharynx. The pharynx passes the foreign matter along to the stomach to eventually be eliminated by the body. As air is inhaled, the mucous membranes of the nose and mouth warm and humidify the air before it enters the lungs.
When you breathe in, the diaphragm moves downward toward the abdomen, and the rib muscles pull the ribs upward and outward. In this way, the volume of the chest cavity is increased. Air pressure in the chest cavity and lungs is reduced, and because gas flows from high pressure to low, air from the environment flows through the nose or mouth into the lungs.
In exhalation, the diaphragm moves upward and the chest wall muscles relax, causing the chest cavity to contract. Air pressure in the lungs rises, so air flows from the lungs and up and out of respiratory system through the nose or mouth.
Every few seconds, with each inhalation, air fills a large portion of the millions of alveoli. In a process called diffusion, oxygen moves from the alveoli to the blood through the capillaries (tiny blood vessels) lining the alveolar walls. Once in the bloodstream, oxygen gets picked up by the hemoglobin in red blood cells. This oxygen-rich blood then flows back to the heart, which pumps it through the arteries to oxygen-hungry tissues throughout the body.
In the tiny capillaries of the body tissues, oxygen is freed from the hemoglobin and moves into the cells. Carbon dioxide, which is produced during the process of diffusion, moves out of these cells into the capillaries, where most of it is dissolved in the plasma of the blood. Blood rich in carbon dioxide then returns to the heart via the veins. From the heart, this blood is pumped to the lungs, where carbon dioxide passes into the alveoli to be exhaled.
Problems of the Lungs and Respiratory System
The respiratory system is susceptible to a number of diseases, and the lungs are prone to a wide range of disorders caused by pollutants in the air.
The most common problems of the respiratory system are:
Asthma. More than 20 million people in the United States have asthma, and it's the #1 reason that kids chronically miss school. Asthma is a chronic inflammatory lung disease that causes airways to tighten and narrow. Often triggered by irritants in the air such as cigarette smoke, asthma flares involve contraction of the muscles and swelling of the lining of the tiny airways. The resulting narrowing of the airways prevents air from flowing properly, causing wheezing and difficulty breathing, sometimes to the point of being life-threatening. Management of asthma starts with an asthma management plan, which usually involves avoiding asthma triggers and sometimes taking medications.
Bronchiolitis. Not to be confused with bronchitis, bronchiolitis is an inflammation of the bronchioles, the smallest branches of the bronchial tree. Bronchiolitis affects mostly infants and young children, and can cause wheezing and serious difficulty breathing. It's usually caused by specific viruses in the wintertime, including respiratory syncytial virus (RSV).
Chronic obstructive pulmonary disease (COPD). COPD is a term that describes two lung diseases — emphysema and chronic bronchitis:
•Long-term smoking often causes emphysema, and although it seldom affects kids and teens, it can have its roots in the teen and childhood years. Talking to your kids about smoking is a key part of preventing smoking-related diseases. In emphysema, the lungs produce an excessive amount of mucus and the alveoli become damaged. It becomes difficult to breathe and get enough oxygen into the blood.
•In bronchitis, a common disease of adults and teens, the membranes lining the larger bronchial tubes become inflamed and an excessive amount of mucus is produced. The person develops a bad cough to get rid of the mucus. Cigarette smoking is a major cause of chronic bronchitis in teens.
Other Conditions
Common cold. Caused by over 200 different viruses that cause inflammation in the upper respiratory tract, the common cold is the most common respiratory infection. Symptoms may include a mild fever, cough, headache, runny nose, sneezing, and sore throat.
Cough. A cough is a symptom of an illness, not an illness itself. There are many different types of cough and many different causes, ranging from not-so-serious to life-threatening. Some of the more common causes affecting kids are the common cold, asthma, sinusitis, seasonal allergies, croup, and pneumonia. Among the most serious causes of cough are tuberculosis (TB) and whooping cough (pertussis).
Cystic fibrosis (CF). Affecting more than 30,000 kids and young adults in the United States, cystic fibrosis is the most common inherited disease affecting the lungs. Affecting primarily the respiratory and digestive systems, CF causes mucus in the body to be abnormally thick and sticky. The mucus can clog the airways in the lungs and make a person more vulnerable to bacterial infections.
Lung cancer. Caused by an abnormal growth of cells in the lungs, lung cancer is a leading cause of death in the United States and is usually caused by smoking cigarettes. It starts in the lining of the bronchi and takes a long time to develop. Symptoms include a persistent cough that may bring up blood, chest pain, hoarseness, and shortness of breath. Radon gas exposure (radon is a gas that occurs in soil and rocks) may also be a cause of lung cancer. Radon is more likely to occur in certain parts of the United States. You can check your home's radon level by purchasing a radon kit at your local home supply or hardware store.
Pneumonia. This inflammation of the lungs usually occurs because of bacterial or viral infection. Pneumonia causes fever and inflammation of lung tissue, and makes breathing difficult because the lungs have to work harder to transfer oxygen into the bloodstream and remove carbon dioxide from the blood. Common causes of pneumonia are influenza and infection with the bacterium Streptococcus pneumoniae.
Pulmonary Hypertension
This condition occurs when the blood pressure in the arteries of the lungs is abnormally high, which means the heart has to work harder to pump blood against the high pressure. Pulmonary hypertension may occur in children because of a heart defect present at birth or because of a health condition such as HIV infection.
Respiratory Diseases of Newborns
Several respiratory conditions can affect a newborn baby just starting to breathe for the first time. Premature babies are at increased risk for conditions such as:
•Respiratory distress syndrome of the newborn. Babies born prematurely may not have enough surfactant in the lungs. Surfactant helps to keep the baby's alveoli open; without surfactant, the lungs collapse and the baby is unable to breathe.
•Apnea of prematurity (AOP). Apnea is a medical term that means someone has stopped breathing. Apnea of prematurity (AOP) is a condition in which premature infants stop breathing for 15 to 20 seconds during sleep. Apnea of prematurity generally occurs after 2 days of life and up to a week of life. The lower the infant's weight and level of prematurity at birth, the more likely the baby is to have AOP spells.
•Bronchopulmonary dysplasia (BPD). BDP involves abnormal development of lung tissue. Sometimes called chronic lung disease or CLD, it's a disease in infants characterized by inflammation and scarring in the lungs. It develops most often in premature babies who are born with underdeveloped lungs.
•Meconium aspiration. Meconium aspiration occurs when a newborn inhales (aspirates) a mixture of meconium (baby's first feces, ordinarily passed after birth) and amniotic fluid during labor and delivery. The inhaled meconium can cause a partial or complete blockage of the baby's airways.
Additional Conditions
•Persistent pulmonary hypertension of the newborn (PPHN). In the uterus, a baby's circulation bypasses the lungs. Normally, when a baby is born and begins to breathe air, his or her body quickly adapts and begins the process of respiration. PPHN occurs when a baby's body doesn't make the normal transition from fetal circulation to newborn circulation. This condition can cause symptoms such as rapid breathing, rapid heart rate, respiratory distress, and cyanosis (blue-tinged skin).
•Transient tachypnea of the newborn (TTN). Rapid breathing in a full-term newborn (more than 60 breaths a minute) is called transient tachypnea.
Although some respiratory diseases can't be prevented, many chronic lung and respiratory illnesses can be prevented by avoiding smoking, staying away from pollutants and irritants, washing hands often to avoid infection, and getting regular medical checkups.
"I pray that this article empowers you to Get A L.I.F.E."
Saturday, June 11, 2011
Kidneys and Urinary Tract
The Importance of the Kidneys and Urinary Tract
Our bodies produce several kinds of wastes, including sweat, carbon dioxide gas, feces (stool), and urine. These wastes exit the body in different ways. Sweat is released through pores in the skin. Water vapor and carbon dioxide are exhaled from the lungs. And undigested food materials are formed into feces in the intestines and excreted from the body as solid waste in bowel movements.
Urine, which is produced by the kidneys, contains the byproducts of metabolism — salts, toxins, and water — that end up in the blood. The kidneys and urinary tract (which includes the kidneys, ureters, bladder, and urethra) filter and eliminate these waste substances from our blood. Without the kidneys, waste products and toxins would soon build up in the blood to dangerous levels.
In addition to eliminating wastes, the kidneys and urinary tract also regulate many important body functions. For example, the kidneys monitor and maintain the body's balance of water, ensuring that our tissues receive enough water to function properly and be healthy.
When doctors take a urine sample, the results reveal how well the kidneys are working. For example, blood, protein, or white blood cells in the urine may indicate injury, inflammation, or infection of the kidneys, and glucose in the urine may be an indication of diabetes.
What They Do
Although the two kidneys work together to perform many vital functions, people can live a normal, healthy life with just one kidney. In fact, some people are born with just one of these bean-shaped organs. If one kidney is removed, the remaining one will enlarge within a few months to take over the role of filtering blood on its own.
Every minute, more than 1 quart (about 1 liter) of blood goes to the kidneys. About one fifth of the blood pumped from the heart goes to the kidneys at any one time.
In addition to filtering blood, producing urine, and ensuring that body tissues receive enough water, the kidneys also regulate blood pressure and the level of vital salts in the blood. By regulating salt levels through production of an enzyme called renin (as well as other substances), the kidneys ensure that blood pressure is regulated.
The kidneys also secrete the hormone erythropoietin, which stimulates and controls red blood cell production (red blood cells carry oxygen throughout the body). In addition, the kidneys help regulate the acid-base balance (or the pH) of the blood and body fluids, which is necessary for the body to function normally.
How They Work
The kidneys are located just under the ribcage in the back, one on each side. The right kidney is located below the liver, so it's a little lower than the left one. Each adult kidney is about the size of a fist. Each has an outer layer called the cortex, which contains the filtering units.
The center part of the kidney, the medulla has 10 to 15 fan-shaped structures called pyramids. These drain urine into cup-shaped tubes called calyxes. A layer of fat surrounds the kidneys to cushion and help hold them in place.
Here's how the kidneys filter blood: Blood travels to each kidney through the renal artery, which enters the kidney at the hilus, the indentation in the kidney that gives it its bean shape. As it enters the cortex, the artery branches to envelope the nephrons — 1 million tiny filtering units in each kidney that remove the harmful substances from the blood.
Each of the nephrons contain a filter called the glomerulus, which contains a network of tiny blood vessels known as capillaries. The fluid filtered from the blood by the glomerulus then travels down a tiny tube-like structure called a tubule, which adjusts the level of salts, water, and wastes that are excreted in the urine.
Filtered blood leaves the kidney through the renal vein and flows back to the heart.
The continuous blood supply entering and leaving the kidneys gives the kidneys their dark red color. While the blood is in the kidneys, water and some of the other blood components (such as acids, glucose, and other nutrients) are reabsorbed back into the bloodstream. Left behind is urine. Urine is a concentrated solution of waste material containing water, urea, a waste product that forms when proteins are broken down), salts, amino acids, byproducts of bile from the liver, ammonia, and any substances that cannot be reabsorbed into the blood. Urine also contains urochrome, a pigmented blood product that gives urine its yellowish color.
The renal pelvis, located near the hilus, collects the urine flowing from the calyxes. From the renal pelvis, urine is transported out of the kidneys through the ureters, tubes that carry the urine out of each kidney to be stored in the urinary bladder — a muscular collection sac in the lower abdomen.
The bladder expands as it fills and can hold about 2 cups (half a liter) of urine at any given time (an average adult produces about 6 cups, or 1½ liters, of urine per day). An adult needs to produce and excrete at least one third of this amount in order to adequately clear waste products from the body. Producing too much or not enough urine may indicate illness.
When the bladder is full, nerve endings in its wall send impulses to the brain. When a person is ready to urinate, the bladder walls contract and the sphincter (a ring-like muscle that guards the exit from the bladder to the urethra) relaxes. The urine is ejected from the bladder and out of the body through the urethra, another tube-like structure. The male urethra ends at the tip of the penis; the female urethra ends just above the vaginal opening.
Problems of the Kidneys and Urinary Tract
Like other systems in the body, the entire urinary tract is subject to diseases and disorders.
In kids, the more common problems include:
Congenital problems of the urinary tract. As a fetus develops in the womb, any part of the urinary tract can grow to an abnormal size or in an abnormal shape or position. One common congenital abnormality (an abnormality that exists at birth) is duplication of the ureters, in which a kidney has two ureters coming from it instead of one. This defect occurs in about 1 out of every 125 births and can cause the kidney to develop problems with repeated infections and scarring over time.
Another congenital problem is horseshoe kidney, where the two kidneys are fused (connected) into one arched kidney that usually functions normally, but is more prone to develop problems later in life. This condition is found in 1 out of every 500 births.
Glomerulonephritis is an inflammation of the glomeruli, the parts of the filtering units (nephrons) of the kidney that contain a network of capillaries (tiny blood vessels). The most common form is post-streptococcal glomerulonephritis, which usually occurs in young children following a case of strep throat. Most kids with this type of nephritis recover fully, but a few can have permanent kidney damage that eventually requires dialysis or a kidney transplant.
High blood pressure (hypertension) can result when the kidneys are impaired by disease. The kidneys control blood pressure by regulating the amount of salt in the body and by producing the enzyme renin that, along with other substances, controls the constriction of muscle cells in the walls of the blood vessels.
Kidney (renal) failure can be acute (sudden) or chronic (occurring over time and usually long lasting or permanent). In either form of kidney failure, the kidneys slow down or stop filtering blood effectively, causing waste products and toxic substances to build up in the blood.
Acute kidney failure may be due to many things, including a bacterial infection, injury, shock, heart failure, poisoning, or drug overdose. Treatment includes correcting the problem that led to the failure and sometimes requires surgery or dialysis. Dialysis involves using a machine or other artificial device to remove the excess salts and water and other wastes from the body when the kidneys are unable to perform this function.
Chronic kidney failure involves a deterioration of kidney function over time. In children, it can result from acute kidney failure that fails to improve, birth defects of the kidney, chronic kidney diseases, repeated kidney infections, or chronic severe high blood pressure. If diagnosed early, chronic kidney failure in children can be treated but usually not reversed. The child will usually require a kidney transplant at some point in the future.
Kidney stones (or nephrolithiasis) result from the buildup of crystallized salts and minerals such as calcium in the urinary tract. Stones (also called calculi) can also form after an infection. If kidney stones are large enough to block the kidney or ureter, they can cause severe abdominal pain. But the stones usually pass through the urinary tract on their own. In some cases, they may need to be removed surgically.
Nephritis is any inflammation of the kidney. It can be caused by infection, medications, an autoimmune disease (such as lupus), or it may be idiopathic (which means the exact cause may not be known or understood). Nephritis is generally detected by protein and blood in the urine.
Nephrotic syndrome is a type of kidney disease that leads to loss of protein in the urine and swelling of the face (often the eyes) or body (often around the genitals). It is most common in children younger than 6 years old and is more prevalent in boys. Nephrotic syndrome is often treated with steroids.
Urinary tract infections (UTIs) are usually caused by intestinal bacteria, such as E. coli, normally found in feces. These bacteria can cause infections anywhere in the urinary tract, including the kidneys. Most UTIs occur in the lower urinary tract, in the bladder and urethra. UTIs occur in both boys and girls. However, uncircumcised males are about 3 to 12 times more likely than circumcised males to develop a UTI before age 1. Although uncircumcised males are about 3 to 12 times more likely than circumcised males to develop a UTI before age 1, most experts don't believe that this is a strong enough reason to recommend routine circumcision for boys. In school-age children, girls are more likely to develop UTIs than boys; this may be because girls have shorter urethras than boys.
Vesicoureteral reflux (VUR) is a condition in which urine abnormally flows backward (or refluxes) from the bladder into the ureters. It may even reach the kidneys, where infection and scarring can occur over time. VUR occurs in 1% of children and tends to run in families. It's often detected after a young child has a first urinary tract infection. Most kids outgrow mild forms of VUR, but some can develop permanent kidney damage and kidney failure later in life.
Wilms' tumor is the most common kidney cancer occurring in children. It is diagnosed most commonly between 2 and 5 years of age and affects males and females equally.
"I pray that this article empowers you to Get A L.I.F.E."
Our bodies produce several kinds of wastes, including sweat, carbon dioxide gas, feces (stool), and urine. These wastes exit the body in different ways. Sweat is released through pores in the skin. Water vapor and carbon dioxide are exhaled from the lungs. And undigested food materials are formed into feces in the intestines and excreted from the body as solid waste in bowel movements.
Urine, which is produced by the kidneys, contains the byproducts of metabolism — salts, toxins, and water — that end up in the blood. The kidneys and urinary tract (which includes the kidneys, ureters, bladder, and urethra) filter and eliminate these waste substances from our blood. Without the kidneys, waste products and toxins would soon build up in the blood to dangerous levels.
In addition to eliminating wastes, the kidneys and urinary tract also regulate many important body functions. For example, the kidneys monitor and maintain the body's balance of water, ensuring that our tissues receive enough water to function properly and be healthy.
When doctors take a urine sample, the results reveal how well the kidneys are working. For example, blood, protein, or white blood cells in the urine may indicate injury, inflammation, or infection of the kidneys, and glucose in the urine may be an indication of diabetes.
What They Do
Although the two kidneys work together to perform many vital functions, people can live a normal, healthy life with just one kidney. In fact, some people are born with just one of these bean-shaped organs. If one kidney is removed, the remaining one will enlarge within a few months to take over the role of filtering blood on its own.
Every minute, more than 1 quart (about 1 liter) of blood goes to the kidneys. About one fifth of the blood pumped from the heart goes to the kidneys at any one time.
In addition to filtering blood, producing urine, and ensuring that body tissues receive enough water, the kidneys also regulate blood pressure and the level of vital salts in the blood. By regulating salt levels through production of an enzyme called renin (as well as other substances), the kidneys ensure that blood pressure is regulated.
The kidneys also secrete the hormone erythropoietin, which stimulates and controls red blood cell production (red blood cells carry oxygen throughout the body). In addition, the kidneys help regulate the acid-base balance (or the pH) of the blood and body fluids, which is necessary for the body to function normally.
How They Work
The kidneys are located just under the ribcage in the back, one on each side. The right kidney is located below the liver, so it's a little lower than the left one. Each adult kidney is about the size of a fist. Each has an outer layer called the cortex, which contains the filtering units.
The center part of the kidney, the medulla has 10 to 15 fan-shaped structures called pyramids. These drain urine into cup-shaped tubes called calyxes. A layer of fat surrounds the kidneys to cushion and help hold them in place.
Here's how the kidneys filter blood: Blood travels to each kidney through the renal artery, which enters the kidney at the hilus, the indentation in the kidney that gives it its bean shape. As it enters the cortex, the artery branches to envelope the nephrons — 1 million tiny filtering units in each kidney that remove the harmful substances from the blood.
Each of the nephrons contain a filter called the glomerulus, which contains a network of tiny blood vessels known as capillaries. The fluid filtered from the blood by the glomerulus then travels down a tiny tube-like structure called a tubule, which adjusts the level of salts, water, and wastes that are excreted in the urine.
Filtered blood leaves the kidney through the renal vein and flows back to the heart.
The continuous blood supply entering and leaving the kidneys gives the kidneys their dark red color. While the blood is in the kidneys, water and some of the other blood components (such as acids, glucose, and other nutrients) are reabsorbed back into the bloodstream. Left behind is urine. Urine is a concentrated solution of waste material containing water, urea, a waste product that forms when proteins are broken down), salts, amino acids, byproducts of bile from the liver, ammonia, and any substances that cannot be reabsorbed into the blood. Urine also contains urochrome, a pigmented blood product that gives urine its yellowish color.
The renal pelvis, located near the hilus, collects the urine flowing from the calyxes. From the renal pelvis, urine is transported out of the kidneys through the ureters, tubes that carry the urine out of each kidney to be stored in the urinary bladder — a muscular collection sac in the lower abdomen.
The bladder expands as it fills and can hold about 2 cups (half a liter) of urine at any given time (an average adult produces about 6 cups, or 1½ liters, of urine per day). An adult needs to produce and excrete at least one third of this amount in order to adequately clear waste products from the body. Producing too much or not enough urine may indicate illness.
When the bladder is full, nerve endings in its wall send impulses to the brain. When a person is ready to urinate, the bladder walls contract and the sphincter (a ring-like muscle that guards the exit from the bladder to the urethra) relaxes. The urine is ejected from the bladder and out of the body through the urethra, another tube-like structure. The male urethra ends at the tip of the penis; the female urethra ends just above the vaginal opening.
Problems of the Kidneys and Urinary Tract
Like other systems in the body, the entire urinary tract is subject to diseases and disorders.
In kids, the more common problems include:
Congenital problems of the urinary tract. As a fetus develops in the womb, any part of the urinary tract can grow to an abnormal size or in an abnormal shape or position. One common congenital abnormality (an abnormality that exists at birth) is duplication of the ureters, in which a kidney has two ureters coming from it instead of one. This defect occurs in about 1 out of every 125 births and can cause the kidney to develop problems with repeated infections and scarring over time.
Another congenital problem is horseshoe kidney, where the two kidneys are fused (connected) into one arched kidney that usually functions normally, but is more prone to develop problems later in life. This condition is found in 1 out of every 500 births.
Glomerulonephritis is an inflammation of the glomeruli, the parts of the filtering units (nephrons) of the kidney that contain a network of capillaries (tiny blood vessels). The most common form is post-streptococcal glomerulonephritis, which usually occurs in young children following a case of strep throat. Most kids with this type of nephritis recover fully, but a few can have permanent kidney damage that eventually requires dialysis or a kidney transplant.
High blood pressure (hypertension) can result when the kidneys are impaired by disease. The kidneys control blood pressure by regulating the amount of salt in the body and by producing the enzyme renin that, along with other substances, controls the constriction of muscle cells in the walls of the blood vessels.
Kidney (renal) failure can be acute (sudden) or chronic (occurring over time and usually long lasting or permanent). In either form of kidney failure, the kidneys slow down or stop filtering blood effectively, causing waste products and toxic substances to build up in the blood.
Acute kidney failure may be due to many things, including a bacterial infection, injury, shock, heart failure, poisoning, or drug overdose. Treatment includes correcting the problem that led to the failure and sometimes requires surgery or dialysis. Dialysis involves using a machine or other artificial device to remove the excess salts and water and other wastes from the body when the kidneys are unable to perform this function.
Chronic kidney failure involves a deterioration of kidney function over time. In children, it can result from acute kidney failure that fails to improve, birth defects of the kidney, chronic kidney diseases, repeated kidney infections, or chronic severe high blood pressure. If diagnosed early, chronic kidney failure in children can be treated but usually not reversed. The child will usually require a kidney transplant at some point in the future.
Kidney stones (or nephrolithiasis) result from the buildup of crystallized salts and minerals such as calcium in the urinary tract. Stones (also called calculi) can also form after an infection. If kidney stones are large enough to block the kidney or ureter, they can cause severe abdominal pain. But the stones usually pass through the urinary tract on their own. In some cases, they may need to be removed surgically.
Nephritis is any inflammation of the kidney. It can be caused by infection, medications, an autoimmune disease (such as lupus), or it may be idiopathic (which means the exact cause may not be known or understood). Nephritis is generally detected by protein and blood in the urine.
Nephrotic syndrome is a type of kidney disease that leads to loss of protein in the urine and swelling of the face (often the eyes) or body (often around the genitals). It is most common in children younger than 6 years old and is more prevalent in boys. Nephrotic syndrome is often treated with steroids.
Urinary tract infections (UTIs) are usually caused by intestinal bacteria, such as E. coli, normally found in feces. These bacteria can cause infections anywhere in the urinary tract, including the kidneys. Most UTIs occur in the lower urinary tract, in the bladder and urethra. UTIs occur in both boys and girls. However, uncircumcised males are about 3 to 12 times more likely than circumcised males to develop a UTI before age 1. Although uncircumcised males are about 3 to 12 times more likely than circumcised males to develop a UTI before age 1, most experts don't believe that this is a strong enough reason to recommend routine circumcision for boys. In school-age children, girls are more likely to develop UTIs than boys; this may be because girls have shorter urethras than boys.
Vesicoureteral reflux (VUR) is a condition in which urine abnormally flows backward (or refluxes) from the bladder into the ureters. It may even reach the kidneys, where infection and scarring can occur over time. VUR occurs in 1% of children and tends to run in families. It's often detected after a young child has a first urinary tract infection. Most kids outgrow mild forms of VUR, but some can develop permanent kidney damage and kidney failure later in life.
Wilms' tumor is the most common kidney cancer occurring in children. It is diagnosed most commonly between 2 and 5 years of age and affects males and females equally.
"I pray that this article empowers you to Get A L.I.F.E."
Saturday, June 4, 2011
The Immune System
The immune system, which is made up of special cells, proteins, tissues, and organs, defends people against germs and microorganisms every day. In most cases, the immune system does a great job of keeping people healthy and preventing infections. But sometimes problems with the immune system can lead to illness and infection.
About the Immune System
The immune system is the body's defense against infectious organisms and other invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease.
The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. The cells involved are white blood cells, or leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.
Leukocytes are produced or stored in many locations in the body, including the thymus, spleen, and bone marrow. For this reason, they're called the lymphoid organs. There are also clumps of lymphoid tissue throughout the body, primarily as lymph nodes, that house the leukocytes.
The leukocytes circulate through the body between the organs and nodes via lymphatic vessels and blood vessels. In this way, the immune system works in a coordinated manner to monitor the body for germs or substances that might cause problems.
The two basic types of leukocytes are:
1.phagocytes, cells that chew up invading organisms
2.lymphocytes, cells that allow the body to remember and recognize previous invaders and help the body destroy them
A number of different cells are considered phagocytes. The most common type is the neutrophil, which primarily fights bacteria. If doctors are worried about a bacterial infection, they might order a blood test to see if a patient has an increased number of neutrophils triggered by the infection. Other types of phagocytes have their own jobs to make sure that the body responds appropriately to a specific type of invader.
The two kinds of lymphocytes are B lymphocytes and T lymphocytes. Lymphocytes start out in the bone marrow and either stay there and mature into B cells, or they leave for the thymus gland, where they mature into T cells. B lymphocytes and T lymphocytes have separate functions: B lymphocytes are like the body's military intelligence system, seeking out their targets and sending defenses to lock onto them. T cells are like the soldiers, destroying the invaders that the intelligence system has identified.
Here's how it works:
When antigens (foreign substances that invade the body) are detected, several types of cells work together to recognize them and respond. These cells trigger the B lymphocytes to produce antibodies, specialized proteins that lock onto specific antigens.
Once produced, these antibodies continue to exist in a person's body, so that if the same antigen is presented to the immune system again, the antibodies are already there to do their job. So if someone gets sick with a certain disease, like chickenpox, that person typically doesn't get sick from it again.
This is also how immunizations prevent certain diseases. An immunization introduces the body to an antigen in a way that doesn't make someone sick, but does allow the body to produce antibodies that will then protect the person from future attack by the germ or substance that produces that particular disease.
Although antibodies can recognize an antigen and lock onto it, they are not capable of destroying it without help. That's the job of the T cells, which are part of the system that destroys antigens that have been tagged by antibodies or cells that have been infected or somehow changed. (Some T cells are actually called "killer cells.") T cells also are involved in helping signal other cells (like phagocytes) to do their jobs.
Antibodies also can neutralize toxins (poisonous or damaging substances) produced by different organisms. Lastly, antibodies can activate a group of proteins called complement that are also part of the immune system. Complement assists in killing bacteria, viruses, or infected cells.
All of these specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity.
Immunity
Humans have three types of immunity — innate, adaptive, and passive:
Innate Immunity
Everyone is born with innate (or natural) immunity, a type of general protection. Many of the germs that affect other species don't harm us. For example, the viruses that cause leukemia in cats or distemper in dogs don't affect humans. Innate immunity works both ways because some viruses that make humans ill — such as the virus that causes HIV/AIDS — don't make cats or dogs sick.
Innate immunity also includes the external barriers of the body, like the skin and mucous membranes (like those that line the nose, throat, and gastrointestinal tract), which are the first line of defense in preventing diseases from entering the body. If this outer defensive wall is broken (as through a cut), the skin attempts to heal the break quickly and special immune cells on the skin attack invading germs.
Adaptive Immunity
The second kind of protection is adaptive (or active) immunity, which develops throughout our lives. Adaptive immunity involves the lymphocytes and develops as people are exposed to diseases or immunized against diseases through vaccination.
Passive Immunity
Passive immunity is "borrowed" from another source and it lasts for a short time. For example, antibodies in a mother's breast milk provide a baby with temporary immunity to diseases the mother has been exposed to. This can help protect the baby against infection during the early years of childhood.
Everyone's immune system is different. Some people never seem to get infections, whereas others seem to be sick all the time. As people get older, they usually become immune to more germs as the immune system comes into contact with more and more of them. That's why adults and teens tend to get fewer colds than kids — their bodies have learned to recognize and immediately attack many of the viruses that cause colds.
Problems of the Immune System
Disorders of the immune system fall into into four main categories:
1.immunodeficiency disorders (primary or acquired)
2.autoimmune disorders (in which the body's own immune system attacks its own tissue as foreign matter)
3.allergic disorders (in which the immune system overreacts in response to an antigen)
4.cancers of the immune system
Immunodeficiency Disorders
Immunodeficiencies occur when a part of the immune system is not present or is not working properly. Sometimes a person is born with an immunodeficiency (known as primary immunodeficiencies), although symptoms of the disorder might not appear until later in life. Immunodeficiencies also can be acquired through infection or produced by drugs (these are sometimes called secondary immunodeficiencies).
Immunodeficiencies can affect B lymphocytes, T lymphocytes, or phagocytes. Examples of primary immunodeficiencies that can affect kids and teens are:
•IgA deficiency is the most common immunodeficiency disorder. IgA is an immunoglobulin that is found primarily in the saliva and other body fluids that help guard the entrances to the body. IgA deficiency is a disorder in which the body doesn't produce enough of the antibody IgA. People with IgA deficiency tend to have allergies or get more colds and other respiratory infections, but the condition is usually not severe.
•Severe combined immunodeficiency (SCID) is also known as the "bubble boy disease" after a Texas boy with SCID who lived in a germ-free plastic bubble. SCID is a serious immune system disorder that occurs because of a lack of both B and T lymphocytes, which makes it almost impossible to fight infections.
•DiGeorge syndrome (thymic dysplasia), a birth defect in which kids are born without a thymus gland, is an example of a primary T-lymphocyte disease. The thymus gland is where T lymphocytes normally mature.
•Chediak-Higashi syndrome and chronic granulomatous disease both involve the inability of the neutrophils to function normally as phagocytes.
Acquired (or secondary) immunodeficiencies usually develop after someone has a disease, although they can also be the result of malnutrition, burns, or other medical problems. Certain medicines also can cause problems with the functioning of the immune system.
Acquired (secondary) immunodeficiencies include:
•HIV (human immunodeficiency virus) infection/AIDS (acquired immunodeficiency syndrome) is a disease that slowly and steadily destroys the immune system. It is caused by HIV, a virus that wipes out certain types of lymphocytes called T-helper cells. Without T-helper cells, the immune system is unable to defend the body against normally harmless organisms, which can cause life-threatening infections in people who have AIDS. Newborns can get HIV infection from their mothers while in the uterus, during the birth process, or during breastfeeding. People can get HIV infection by having unprotected sexual intercourse with an infected person or from sharing contaminated needles for drugs, steroids, or tattoos.
•Immunodeficiencies caused by medications. Some medicines suppress the immune system. One of the drawbacks of chemotherapy treatment for cancer, for example, is that it not only attacks cancer cells, but other fast-growing, healthy cells, including those found in the bone marrow and other parts of the immune system. In addition, people with autoimmune disorders or who have had organ transplants may need to take immunosuppressant medications, which also can reduce the immune system's ability to fight infections and can cause secondary immunodeficiency.
Autoimmune Disorders
In autoimmune disorders, the immune system mistakenly attacks the body's healthy organs and tissues as though they were foreign invaders. Autoimmune diseases include:
•Lupus, a chronic disease marked by muscle and joint pain and inflammation (the abnormal immune response also may involve attacks on the kidneys and other organs)
•Juvenile rheumatoid arthritis, a disease in which the body's immune system acts as though certain body parts (such as the joints of the knee, hand, and foot) are foreign tissue and attacks them
•Scleroderma, a chronic autoimmune disease that can lead to inflammation and damage of the skin, joints, and internal organs
•Ankylosing spondylitis, a disease that involves inflammation of the spine and joints, causing stiffness and pain
•Juvenile dermatomyositis, a disorder marked by inflammation and damage of the skin and muscles
Allergic Disorders
Allergic disorders occur when the immune system overreacts to exposure to antigens in the environment. The substances that provoke such attacks are called allergens. The immune response can cause symptoms such as swelling, watery eyes, and sneezing, and even a life-threatening reaction called anaphylaxis. Medications called antihistamines can relieve most symptoms.
Allergic disorders include:
•Asthma, a respiratory disorder that can cause breathing problems, frequently involves an allergic response by the lungs. If the lungs are oversensitive to certain allergens (like pollen, molds, animal dander, or dust mites), it can trigger breathing tubes in the lungs to become narrowed, leading to reduced airflow and making it hard for a person to breathe.
•Eczema is an itchy rash also known as atopic dermatitis. Although atopic dermatitis is not necessarily caused by an allergic reaction, it more often occurs in kids and teens who have allergies, hay fever, or asthma or who have a family history of these conditions.
•Allergies of several types can occur in kids and teens. Environmental allergies (to dust mites, for example), seasonal allergies (such as hay fever), drug allergies (reactions to specific medications or drugs), food allergies (such as to nuts), and allergies to toxins (bee stings, for example) are the common conditions people usually refer to as allergies.
Cancers of the Immune System
Cancer occurs when cells grow out of control. This also can happen with the cells of the immune system. Lymphoma involves the lymphoid tissues and is one of the more common childhood cancers. Leukemia, which involves abnormal overgrowth of leukocytes, is the most common childhood cancer. With current medications most cases of both types of cancer in kids and teens are curable.
Although immune system disorders usually can't be prevented, you can help your child's immune system stay stronger and fight illnesses by staying informed about your child's condition and working closely with your doctor.
"I pray that this article empowers you to Get A L.I.F.E."
About the Immune System
The immune system is the body's defense against infectious organisms and other invaders. Through a series of steps called the immune response, the immune system attacks organisms and substances that invade body systems and cause disease.
The immune system is made up of a network of cells, tissues, and organs that work together to protect the body. The cells involved are white blood cells, or leukocytes, which come in two basic types that combine to seek out and destroy disease-causing organisms or substances.
Leukocytes are produced or stored in many locations in the body, including the thymus, spleen, and bone marrow. For this reason, they're called the lymphoid organs. There are also clumps of lymphoid tissue throughout the body, primarily as lymph nodes, that house the leukocytes.
The leukocytes circulate through the body between the organs and nodes via lymphatic vessels and blood vessels. In this way, the immune system works in a coordinated manner to monitor the body for germs or substances that might cause problems.
The two basic types of leukocytes are:
1.phagocytes, cells that chew up invading organisms
2.lymphocytes, cells that allow the body to remember and recognize previous invaders and help the body destroy them
A number of different cells are considered phagocytes. The most common type is the neutrophil, which primarily fights bacteria. If doctors are worried about a bacterial infection, they might order a blood test to see if a patient has an increased number of neutrophils triggered by the infection. Other types of phagocytes have their own jobs to make sure that the body responds appropriately to a specific type of invader.
The two kinds of lymphocytes are B lymphocytes and T lymphocytes. Lymphocytes start out in the bone marrow and either stay there and mature into B cells, or they leave for the thymus gland, where they mature into T cells. B lymphocytes and T lymphocytes have separate functions: B lymphocytes are like the body's military intelligence system, seeking out their targets and sending defenses to lock onto them. T cells are like the soldiers, destroying the invaders that the intelligence system has identified.
Here's how it works:
When antigens (foreign substances that invade the body) are detected, several types of cells work together to recognize them and respond. These cells trigger the B lymphocytes to produce antibodies, specialized proteins that lock onto specific antigens.
Once produced, these antibodies continue to exist in a person's body, so that if the same antigen is presented to the immune system again, the antibodies are already there to do their job. So if someone gets sick with a certain disease, like chickenpox, that person typically doesn't get sick from it again.
This is also how immunizations prevent certain diseases. An immunization introduces the body to an antigen in a way that doesn't make someone sick, but does allow the body to produce antibodies that will then protect the person from future attack by the germ or substance that produces that particular disease.
Although antibodies can recognize an antigen and lock onto it, they are not capable of destroying it without help. That's the job of the T cells, which are part of the system that destroys antigens that have been tagged by antibodies or cells that have been infected or somehow changed. (Some T cells are actually called "killer cells.") T cells also are involved in helping signal other cells (like phagocytes) to do their jobs.
Antibodies also can neutralize toxins (poisonous or damaging substances) produced by different organisms. Lastly, antibodies can activate a group of proteins called complement that are also part of the immune system. Complement assists in killing bacteria, viruses, or infected cells.
All of these specialized cells and parts of the immune system offer the body protection against disease. This protection is called immunity.
Immunity
Humans have three types of immunity — innate, adaptive, and passive:
Innate Immunity
Everyone is born with innate (or natural) immunity, a type of general protection. Many of the germs that affect other species don't harm us. For example, the viruses that cause leukemia in cats or distemper in dogs don't affect humans. Innate immunity works both ways because some viruses that make humans ill — such as the virus that causes HIV/AIDS — don't make cats or dogs sick.
Innate immunity also includes the external barriers of the body, like the skin and mucous membranes (like those that line the nose, throat, and gastrointestinal tract), which are the first line of defense in preventing diseases from entering the body. If this outer defensive wall is broken (as through a cut), the skin attempts to heal the break quickly and special immune cells on the skin attack invading germs.
Adaptive Immunity
The second kind of protection is adaptive (or active) immunity, which develops throughout our lives. Adaptive immunity involves the lymphocytes and develops as people are exposed to diseases or immunized against diseases through vaccination.
Passive Immunity
Passive immunity is "borrowed" from another source and it lasts for a short time. For example, antibodies in a mother's breast milk provide a baby with temporary immunity to diseases the mother has been exposed to. This can help protect the baby against infection during the early years of childhood.
Everyone's immune system is different. Some people never seem to get infections, whereas others seem to be sick all the time. As people get older, they usually become immune to more germs as the immune system comes into contact with more and more of them. That's why adults and teens tend to get fewer colds than kids — their bodies have learned to recognize and immediately attack many of the viruses that cause colds.
Problems of the Immune System
Disorders of the immune system fall into into four main categories:
1.immunodeficiency disorders (primary or acquired)
2.autoimmune disorders (in which the body's own immune system attacks its own tissue as foreign matter)
3.allergic disorders (in which the immune system overreacts in response to an antigen)
4.cancers of the immune system
Immunodeficiency Disorders
Immunodeficiencies occur when a part of the immune system is not present or is not working properly. Sometimes a person is born with an immunodeficiency (known as primary immunodeficiencies), although symptoms of the disorder might not appear until later in life. Immunodeficiencies also can be acquired through infection or produced by drugs (these are sometimes called secondary immunodeficiencies).
Immunodeficiencies can affect B lymphocytes, T lymphocytes, or phagocytes. Examples of primary immunodeficiencies that can affect kids and teens are:
•IgA deficiency is the most common immunodeficiency disorder. IgA is an immunoglobulin that is found primarily in the saliva and other body fluids that help guard the entrances to the body. IgA deficiency is a disorder in which the body doesn't produce enough of the antibody IgA. People with IgA deficiency tend to have allergies or get more colds and other respiratory infections, but the condition is usually not severe.
•Severe combined immunodeficiency (SCID) is also known as the "bubble boy disease" after a Texas boy with SCID who lived in a germ-free plastic bubble. SCID is a serious immune system disorder that occurs because of a lack of both B and T lymphocytes, which makes it almost impossible to fight infections.
•DiGeorge syndrome (thymic dysplasia), a birth defect in which kids are born without a thymus gland, is an example of a primary T-lymphocyte disease. The thymus gland is where T lymphocytes normally mature.
•Chediak-Higashi syndrome and chronic granulomatous disease both involve the inability of the neutrophils to function normally as phagocytes.
Acquired (or secondary) immunodeficiencies usually develop after someone has a disease, although they can also be the result of malnutrition, burns, or other medical problems. Certain medicines also can cause problems with the functioning of the immune system.
Acquired (secondary) immunodeficiencies include:
•HIV (human immunodeficiency virus) infection/AIDS (acquired immunodeficiency syndrome) is a disease that slowly and steadily destroys the immune system. It is caused by HIV, a virus that wipes out certain types of lymphocytes called T-helper cells. Without T-helper cells, the immune system is unable to defend the body against normally harmless organisms, which can cause life-threatening infections in people who have AIDS. Newborns can get HIV infection from their mothers while in the uterus, during the birth process, or during breastfeeding. People can get HIV infection by having unprotected sexual intercourse with an infected person or from sharing contaminated needles for drugs, steroids, or tattoos.
•Immunodeficiencies caused by medications. Some medicines suppress the immune system. One of the drawbacks of chemotherapy treatment for cancer, for example, is that it not only attacks cancer cells, but other fast-growing, healthy cells, including those found in the bone marrow and other parts of the immune system. In addition, people with autoimmune disorders or who have had organ transplants may need to take immunosuppressant medications, which also can reduce the immune system's ability to fight infections and can cause secondary immunodeficiency.
Autoimmune Disorders
In autoimmune disorders, the immune system mistakenly attacks the body's healthy organs and tissues as though they were foreign invaders. Autoimmune diseases include:
•Lupus, a chronic disease marked by muscle and joint pain and inflammation (the abnormal immune response also may involve attacks on the kidneys and other organs)
•Juvenile rheumatoid arthritis, a disease in which the body's immune system acts as though certain body parts (such as the joints of the knee, hand, and foot) are foreign tissue and attacks them
•Scleroderma, a chronic autoimmune disease that can lead to inflammation and damage of the skin, joints, and internal organs
•Ankylosing spondylitis, a disease that involves inflammation of the spine and joints, causing stiffness and pain
•Juvenile dermatomyositis, a disorder marked by inflammation and damage of the skin and muscles
Allergic Disorders
Allergic disorders occur when the immune system overreacts to exposure to antigens in the environment. The substances that provoke such attacks are called allergens. The immune response can cause symptoms such as swelling, watery eyes, and sneezing, and even a life-threatening reaction called anaphylaxis. Medications called antihistamines can relieve most symptoms.
Allergic disorders include:
•Asthma, a respiratory disorder that can cause breathing problems, frequently involves an allergic response by the lungs. If the lungs are oversensitive to certain allergens (like pollen, molds, animal dander, or dust mites), it can trigger breathing tubes in the lungs to become narrowed, leading to reduced airflow and making it hard for a person to breathe.
•Eczema is an itchy rash also known as atopic dermatitis. Although atopic dermatitis is not necessarily caused by an allergic reaction, it more often occurs in kids and teens who have allergies, hay fever, or asthma or who have a family history of these conditions.
•Allergies of several types can occur in kids and teens. Environmental allergies (to dust mites, for example), seasonal allergies (such as hay fever), drug allergies (reactions to specific medications or drugs), food allergies (such as to nuts), and allergies to toxins (bee stings, for example) are the common conditions people usually refer to as allergies.
Cancers of the Immune System
Cancer occurs when cells grow out of control. This also can happen with the cells of the immune system. Lymphoma involves the lymphoid tissues and is one of the more common childhood cancers. Leukemia, which involves abnormal overgrowth of leukocytes, is the most common childhood cancer. With current medications most cases of both types of cancer in kids and teens are curable.
Although immune system disorders usually can't be prevented, you can help your child's immune system stay stronger and fight illnesses by staying informed about your child's condition and working closely with your doctor.
"I pray that this article empowers you to Get A L.I.F.E."
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