Gastrointestinal Tract

All vital organs begin to lose some function as you age. Aging changes have been found in all of the body's cells, tissues and organs, and these changes affect the functioning of all body systems.

Living tissue is made up of cells. There are many different types of cells, but all have the same basic structure. Tissues are layers of similar cells that perform a specific function. The various kinds of tissues group together to form organs.

There are four basic types of tissue:

• Connective tissue supports other tissues and binds them together. This includes bone, blood, and lymph tissues in addition to the tissues that give support and structure to the skin and internal organs.
• Epithelial tissue provides a covering for deeper body layers. The skin and the linings of the various passages inside the body are made of epithelial tissue.
• Muscle tissue includes three types of tissue:
  • Striated muscles, such as those that that move the skeleton (also called voluntary muscle)
  • Smooth muscles (also called involuntary muscle), such as the muscles that surround the stomach and other internal organs
  • Cardiac muscle, which makes up most of the heart wall (also involuntary muscle)
• Nerve tissue is made up of nerve cells (neurons) and is used to carry messages to and from various parts of the body. The brain is made of nerve tissue.

AGING CHANGES

Cells are the basic building blocks of tissues. All cells experience changes with aging. They become larger and are less able to divide and reproduce. Among other changes, there is an increase in pigments and fatty substances inside the cell (lipids). Many cells lose their ability to function, or they begin to function abnormally.

Waste products accumulate in tissue with aging. A fatty brown pigment called lipofuscin collects in many tissues, as do other fatty substances.

Connective tissue changes, becoming increasingly stiff. This makes the organs, blood vessels, and airways more rigid. Cell membranes change, so many tissues have more trouble receiving oxygen and nutrients and getting rid of carbon dioxide and wastes.

Many tissues lose mass. This process is called atrophy. Some tissues become lumpy (nodular) or more rigid.

Because of cell and tissue changes, your organs also change as you age. Aging organs gradually but progressively lose function, and there is a decrease in the maximum functioning capacity. Most people do not notice this loss, because you seldom need to use your organs to their fullest capability.

Organs have a reserve ability to function beyond the usual needs. For example, the heart of a 20-year-old is capable of pumping about 10 times the amount that is actually needed to preserve life. After age 30, an average of 1% of this reserve is lost each year.

The most significant changes in organ reserve occur in the heart, lungs, and kidneys. The amount of reserve lost varies between people and between different organs in a single person.

These changes appear slowly and over a long period of time. Even so, when an organ is worked harder than usual it may not be able to increase function. Sudden heart failure or other problems can develop when the body is worked harder than usual. Things that produce an extra workload (body stressors) include the following:

• Certain medications
• Illness
• Significant life changes
• Suddenly increased physical demands on the body, for example:
  • A sudden change in activity
  • Exposure to a higher altitude

Loss of reserve also makes it harder to restore equilibrium in the body. Drugs are detoxified at a slower rate. Lower doses of medications may be needed, and side effects become more common.

Medication side effects can mimic the symptoms of many diseases, so it is easy to mistake a drug reaction for an illness. Some medications have entirely different side effects in the elderly than in younger people.

AGING THEORY

No one really knows how and why people change as they get older. Some theories claim that aging is caused by accumulated injuries from ultraviolet light, wear and tear on the body, by-products of metabolism, and so on. Other theories view aging as a predetermined, genetically-controlled process.

However, no theory sufficiently explains all the changes of the aging process. Aging is a complex and varied process that varies in how it affects different people and even different organs. Most gerontologists (people who study aging) feel that aging is the cumulative effect of the interaction of many lifelong influences. These influences include heredity, environment, cultural influences, diet, exercise and leisure, past illnesses, and many other factors.

Unlike the changes of adolescence, which are predictable to within a few years, each person ages at a unique rate. Some systems begin aging as early as age 30. Other aging processes are not common until much later.

Although some changes typically occur with aging, they occur at different rates and to different extents. There is no reliable way to predict specifically how you will age.

TERMS

• ATROPHY
  • Cells shrink. If enough cells decrease in size, the entire organ atrophies. This is often a normal aging change and can occur in any tissue. It is most common in skeletal muscle, the heart, the brain, and the secondary sex organs (such as the breasts).
  • The cause of atrophy is unknown, but may include reduced use, decreased workload, decreased blood supply or nutrition to the cells, and reduced stimulation by nerves or hormones.
• HYPERTROPHY
  • Cells enlarge. This size increase is caused by an increase in cellular proteins, such as the cell wall and internal cell structures, not an increase in the cell's fluid.
  • When some cells atrophy, others may hypertrophy in an attempt to compensate for loss of cell mass.
• HYPERPLASIA
  • The number of cells increases. There is an increased rate of cell division.
  • Hyperplasia usually occurs in an attempt to compensate for loss of cells. It allows some organs and tissues to regenerate, including the skin, the lining of the intestines, the liver and the bone marrow. The liver is especially good at regeneration. It can replace up to 70% of its structure within 2 weeks after an injury.
  • Tissues that have limited ability to regenerate include bone, cartilage, and smooth muscle (such as the muscles around the intestines). Tissues that seldom or never regenerate include nerves, skeletal muscle, heart muscle, and the lens of the eye. When injured, these tissues are replaced with scar tissue.
• DYSPLASIA
  • The size, shape, or organization of mature cells becomes abnormal. This is also called atypical hyperplasia.
  • Dysplasia is fairly common in the cells of the cervix and the lining of the respiratory tract.
• NEOPLASIA
  • The formation of tumors, either cancerous (malignant) or noncancerous (benign).
  • Neoplastic cells often reproduce rapidly. They may have unusual shapes and abnormal function.

RELATED TOPICS

• Aging changes in hormone production
• Aging changes in immunity
• Aging changes in the skin
• Aging changes in sleep
• Aging changes in the bones, muscles, and joints
• Aging changes in the breast
• Aging changes in the face
• Aging changes in the female reproductive system
• Aging changes in the heart and blood vessels
• Aging changes in the kidneys
• Aging changes in the lungs
• Aging changes in the male reproductive system
• Aging changes in the nervous system

Martin GM. Biology of aging. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 22.

An annular pancreas is a ring of pancreatic tissue that encircles the duodenum (the first part of the small intestine). Normally, the pancreas sits next to, but does not surround the duodenum.

Annular pancreas is a congenital defect, which means it is present at birth. Symptoms occur when the ring of pancreas squeezes and narrows the small intestine so that food cannot pass easily or at all.

Newborns may have symptoms of complete blockage of the intestine. However, up to half of people with this condition do not have symptoms until adulthood. There are also cases that are not detected because the symptoms are mild.

Conditions that may be associated with annular pancreas include:

• Down syndrome
• Other congenital gastrointestinal problems
• Pancreatitis
• Excessive amniotic fluid during pregnancy (polyhydramnios)

Newborns may not tolerate feedings. They may spit up more than normal, not drink enough breast milk or formula, and cry.

Adult symptoms may include:

• Fullness after eating
• Nausea or vomiting

Tests include:

• Abdominal ultrasound
• Abdominal x-ray
• CT scan
• Upper GI and small bowel series

Surgical bypass of the blocked part of the duodenum is the usual treatment for this disorder.

The outcome is usually good with surgery.

• Obstructive jaundice
• Pancreatitis (inflammation of the pancreas)
• Peptic ulcer
• Perforation (tearing a hole) of the intestine due to obstruction
• Peritonitis

Call for an appointment with your health care provider if you or your child have any symptoms of annular pancreas.

Russo MA, Redel CA. Anatomy, histology, embryology, and developmental anomalies of the stomach and duodenum. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger & Fordtran's Gastrointestinal and Liver Disease. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 45.

Hepatic ischemia is a condition in which the liver does not get enough blood or oxygen, causing injury to liver cells.

Ischemic hepatitis; Shock liver

Low blood pressure from any condition can lead to hepatic ischemia. Such conditions may include:

• Abnormal heart rhythms
• Dehydration
• Heart failure
• Infection
• Severe bleeding

Other causes may include:

• Large blood clots in the main artery to the liver (hepatic artery) after a transplant
• Swelling of blood vessels (vasculitis)

If low blood pressure continues for a long time, you may feel weak and lightheaded. However, the period of low blood pressure may be brief and produce no symptoms. Damage to the liver cells usually does not cause symptoms.

Blood levels of liver enzymes, such as AST and ALT, typically rise 1 - 3 days after the episode of low blood pressure. Levels of another enzyme in the blood, LDH, are also usually high.

Treatment depends on the cause of the low blood pressure. Low blood pressure must be treated so that the liver receives enough blood. The illness causing the problem must also be treated.

Patients generally recover if the illness causing hepatic ischemia can be treated. Death from liver failure due to hepatic ischemia is very rare.

Liver failure is a rare but life-threatening complication.

See your health care provider right away if you have persistent weakness or symptoms of shock or dehydration.

Quickly treating the causes of low blood pressure may prevent hepatic ischemia.

Jain R, Thiele D. Gastrointestinal and hepatic manifestations of systemic diseases. In: Feldman M, Friedman LS, Sleisenger MH, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 34.

Mineral oil is a liquid oil produced from petroleum. Mineral oil overdose occurs when someone accidentally or intentionally takes more than the normal or recommended amount of this substance.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control Center at 1-800-222-1222.

Mineral oil

Mineral oil is sold by itself. It may also be found in some:

• Antacids
• Diaper rashmedications
• Eye care products
• Hemorrhoidmedications
• Laxatives

Note: This list may not include every product that contains mineral oil.

Symptoms are due to mineral oil's laxative action and may include:

• Abdominal pain
• Dehydration(from severe diarrhea)
• Diarrhea
• Nausea
• Vomiting

Seek immediate medical help. Do NOT make a person throw up unless told to do so by Poison Control or a health care professional.

Determine the following information:

• Patient's age, weight, and condition
• Name of the product (ingredients and strengths, if known)
• Time it was swallowed
• Amount swallowed

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container with you to the hospital, if possible.

See: Poison control center - emergency number

The health care provider will measure and monitor your vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated as appropriate. You may receive:

• Activated charcoal
• Breathing support
• Fluids through a vein (by IV)
• Tube through the mouth into the stomach to wash out the stomach (gastric lavage)

How well you do depends on the amount of poison swallowed and how quickly treatment is received. The faster you get medical help, the better the chance for recovery.

Mineral oil is relatively nontoxic, and recovery is likely.

White SR, Hedge MW. Gastrointestinal toxicology. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose. 4th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 13.

Bleeding refers to the loss of blood. Bleeding can happen inside the body (internally) or outside the body (externally). It may occur:

• Inside the body when blood leaks from blood vessels or organs
• Outside the body when blood flows through a natural opening (such as the vagina, mouth, or rectum)
• Outside the body when blood moves through a break in the skin

Blood loss; Open injury bleeding

Always seek emergency assistance for severe bleeding, and if internal bleeding is suspected. Internal bleeding can rapidly become life threatening, and immediate medical care is needed.

Serious injuries don't always bleed heavily, and some relatively minor injuries (for example, scalp wounds) can bleed quite a lot. People who take blood-thinning medication or who have a bleeding disordersuch as hemophiliamay bleed excessively and quickly because their blood does not clot properly. Bleeding in such people requires immediate medical attention.

Direct pressure will stop most external bleeding, and is the most important first aid step.

Always wash your hands before (if possible) and after giving first aid to someone who is bleeding, in order to avoid infection.

Try to use latex gloves when treating someone who is bleeding. Latex gloves should be in every first aid kit. People allergic to latex can use a non-latex, synthetic glove. You can catch viral hepatitis if you touch infected blood, and HIV can be spread if infected blood gets into an open wound -- even a small one.

Although puncture wounds usually don't bleed very much, they carry a high risk of infection. Seek medical care to prevent tetanus or other infection.

Abdominal and chest wounds can be very serious because of the possibility of severe internal bleeding. They may not look very serious, but can result in shock. Seek immediate medical care for any abdominal or chest wound. If organs are showing through the wound, do not try to push them back into place. Cover the injury with a moistened cloth or bandage, and apply only very gentle pressure to stop the bleeding.

Blood loss can cause bruises (blood collected under the skin), which usually result from a blow or a fall. They are dark, discolored areas on the skin. Apply a cool compress to the area as soon as possible to reduce swelling. Wrap the ice in a towel and place the towel over the injury. Do not place ice directly on the skin.

Bleeding can be caused by injuries or can occur spontaneously. Spontaneous bleeding is most commonly caused by problems with the joints or the gastrointestinal or urogenital tracts.

• Blood coming from an open wound
• Bruising
• Shock, which may cause any of the following symptoms:
  • Confusion or decreasing alertness
  • Clammy skin
  • Dizziness or light-headednessafter an injury
  • Low blood pressure
  • Paleness(pallor)
  • Rapid pulse, increased heart rate
  • Shortness of breath
  • Weakness

Symptoms of internal bleeding may also include:

• Abdominal pain
• Abdominal swelling
• Chest pain
• External bleeding through a natural opening
  • Blood in the stool (appears black, maroon, or bright red)
  • Blood in the urine (appears red, pink, or tea-colored)
  • Blood in the vomit (looks bright red, or brown like coffee-grounds)
  • Vaginal bleeding (heavier than usual or after menopause)

First aid is appropriate for external bleeding. If bleeding is severe, or if shock or internal bleeding is suspected, get emergency help immediately.

1. Calm and reassure the person. The sight of blood can be very frightening.
2. If the wound is superficial, wash it with soap and warm water and pat dry. Superficial wounds or scrapes are injuries that affect the top layers of skin and bleeding from such wounds is often described as "oozing," because it is slow.
3. Lay the person down. This reduces the chances of fainting by increasing blood flow to the brain. When possible, raise up the part of the body that is bleeding.
4. Remove any obvious loose debris or dirt from a wound. If an object such as a knife, stick, or arrow becomes stuck in the body, DO NOT remove it. Doing so may cause more damage and may increase bleeding. Place pads and bandages around the object and tape the object in place.
5. Put pressure directly on an outer wound with a sterile bandage, clean cloth, or even a piece of clothing. If nothing else is available, use your hand. Direct pressure is best for outside bleeding, except for an eye injury.
6. Maintain pressure until the bleeding stops. When it has stopped, tightly wrap the wound dressing with adhesive tape or a piece of clean clothing. Place a cold pack over the dressing. Do not peek to see if the bleeding has stopped.
7. If bleeding continues and seeps through the material being held on the wound, do not remove it. Simply place another cloth over the first one. Be sure to seek medical attention.
8. If the bleeding is severe, get medical help and take steps to prevent shock. Keep the injured body part completely still. Lay the person flat, raise the feet about 12 inches, and cover the person with a coat or blanket. However, DO NOT move the person if there has been a head, neck, back, or leg injury, as doing so may make the injury worse. Get medical help as soon as possible.

• DO NOT apply a tourniquet to control bleeding, except as a last resort. Doing so may cause more harm than good. A tourniquet should be used only in a life-threatening situation and should be applied by an experienced person
• If continuous pressure hasn't stopped the bleeding and bleeding is extremely severe, a tourniquet may be used until medical help arrives or bleeding is controllable.
  • It should be applied to the limb between the bleeding site and the heart and tightened so bleeding can be controlled by applying direct pressure over the wound.
  • To make a tourniquet, use bandages 2 to 4 inches wide and wrap them around the limb several times. Tie a half or square knot, leaving loose ends long enough to tie another knot. A stick or a stiff rod should be placed between the two knots. Twist the stick until the bandage is tight enough to stop the bleeding and then secure it in place.
  • Check the tourniquet every 10 to 15 minutes. If the bleeding becomes controllable, (manageable by applying direct pressure), release the tourniquet.
• DO NOT peek at a wound to see if the bleeding is stopping. The less a wound is disturbed, the more likely it is that you'll be able to control the bleeding
• DO NOT probe a wound or pull out any embedded object from a wound. This will usually cause more bleeding and harm
• DO NOT remove a dressing if it becomes soaked with blood. Instead, add a new one on top
• DO NOT try to clean a large wound. This can cause heavier bleeding
• DO NOT try to clean a wound after you get the bleeding under control. Get medical help

Seek medical help if:

• Bleeding can't be controlled, or is associated with a serious injury
• The wound might need stitches, or if gravel or dirt cannot be removed easily with gentle cleaning
• You think there may be internal bleeding or shock
• Signs of infection develop, including increased pain, redness, swelling, yellow or brown fluid, swollen lymph nodes, fever, or red streaks spreading from the site toward the heart
• The injury involves an animal or human bite
• The patient has not had a tetanus shot in the last 5-10 years

Use good judgment and keep knives and sharp objects away from small children.

Stay up-to-date on vaccinations, especially the tetanus immunization.

Hydrogen peroxide is a liquid commonly used to fight germs. Hydrogen peroxide poisoning occurs when large amounts of the liquid come in contact with the lungs or eyes.

This is for information only and not for use in the treatment or management of an actual poison exposure. If you have an exposure, you should call your local emergency number (such as 911) or the National Poison Control Center at 1-800-222-1222.

Hydrogen peroxide

• Hydrogen peroxide
• Hair bleach
• Some contact lens disinfectants

Note: Household hydrogen peroxide has a 3% concentration.That means it contains 97% water and 3% hydrogen peroxide. Hair bleaches usually have a concentration of greater than 6%. Some industrial strength solutions contain more than 10% hydrogen perioxide.

• Abdominal pain and cramping
• Breathing difficulty (if large concentrations were swallowed)
• Body aches
• Burns in the mouth and throat
• Eye burns
• Seizures (rare)
• Stomach swelling
• Temporary white color to the skin
• Vomiting

Seek immediate medical help. Do NOT make a person throw up unless told to do so by poison control or a health care professional.

If the chemical is on the skin or in the eyes, flush with lots of water for at least 15 minutes.

Determine the following information:

• Patient's age, weight, and condition
• Name of the product (ingredients and strengths, if known)
• Time it was swallowed
• Amount swallowed

The National Poison Control Center (1-800-222-1222) can be called from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

Take the container with you to the hospital, if possible.

See: Poison control center - emergency number

The health care provider will measure and monitor the patient's vital signs, including temperature, pulse, breathing rate, and blood pressure.

Symptoms will be treated as appropriate. The patient may need a tube down the throat into the stomach (gastric tube) to relieve gas pressure.

Most contact with household strength hydrogen peroxide is relatively harmless. Inappropriate exposure to industrial strength hydrogen peroxide can be dangerous.

White SR, Hedge MW. Gastrointestinal toxicology. In: Shannon MW, Borron SW, Burns MJ, eds. Haddad and Winchester's Clinical Management of Poisoning and Drug Overdose. 4th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 13.