Acute gastroenteritis is usually caused by bacteria and protozoan. In the Philippines, one of the mostcommon causes of acute gastroenteritis is E. histolytica. The pathologic process starts with ingestion of fecallycontaminated food and water. The organism affects the body through direct invasion and by endotoxin beingreleased by the organism. Through these two processes the bowel mucosal lining is stimulated and destroyed theeventually lead to attempted defecation or tenesmus as the body tries to get rid of the foreign organism in thestomach.

The client with acute gastroenteritis may also report excessive gas formation that may leads toabdominal distention and passing of flatus due to digestive and absorptive malfunction in the system. Feeling offullness and the increase motility of the gastrointestinal tract may progress to nausea and vomiting andincreasing frequency of defecation. Abdominal pain and feeling of fullness maybe relieved only when thepatient is able to pass a flatus.

As the destruction of the bowel continues the mucosal lining erodes due to toxin, direct invasion of theorganism and the action of the hydrochloric acid of the stomach. As the protective coating of the stomach erodesthe digestive capabilities of the acid helps in destroying the stomach lining. Pain or tenderness of the abdomenis then felt by the patient. When the burrows or ulceration reaches the blood vessels in the stomach bleedingwill be induced. Dysentery may be characterized by melena or hematochezia depending on the site and quantityof bleeding that may ensue. Signs of bleeding may be observed also through hematemesis.

As the bowel is stimulated by the organism and its toxin, the intestinal tract secretes water andelectrolytes in the intestinal lumen. The body secretes and therefore lost Chloride and bicarbonate ions in thebowel as the body try to get rid of the organism by increasing peristalsis and number of defecation. Sodium andwater reabsorption in the bowel is inhibited with the lost of the two electrolytes.

Mild diarrhea is characterized by 2-3 stool, borborygmi (hyperactive bowel sound),fluid and electrolyte imbalance and hypernatremia. When the condition continue to progress, protein in the body is excreted to the lumen that further decreases the reabsorption and the body become overwhelmed that leads to intense diarrhea with more than 10 watery stool. Serious fluid volume deficit may lead to hypovolemic shock and eventually death.

Gastroenteritis Overview

If a human adult’s digestive tract were stretched out, it would be 6 to 9 m (20 to 30 ft)

long. In humans, digestion begins in the mouth, where both mechanical and chemical digestion

occur. The mouth quickly converts food into a soft, moist mass. The muscular tongue pushes the

food against the teeth, which cut, chop, and grind the food. Glands in the cheek linings secrete

mucus, which lubricates the food, making it easier to chew and swallow. Three pairs of glands

empty saliva into the mouth through ducts to moisten the food. Saliva contains the enzyme

ptyalin, which begins to hydrolyze (break down) starch—a carbohydrate manufactured by green

plants.Once food has been reduced to a soft mass, it is ready to be swallowed. The

tongue pushes this mass—called a bolus—to the back of the mouth and into the pharynx. This

cavity between the mouth and windpipe serves as a passageway both for food on its way down

the alimentary canal and for air passing into the windpipe. The epiglottis, a flap of cartilage,

covers the trachea (windpipe) when a person swallows. This action of the epiglottis prevents

choking by directing food from the windpipe and toward the stomach.

MouthThe mouth plays a role in digestion, speech, and breathing. Digestion begins

when food enters the mouth. Teeth break down food and the muscular tongue pushes food back

toward the pharynx, or throat. Three salivary glands—the sublingual gland, the submandibular

gland, and the parotid gland—secrete enzymes that partially digest food into a soft, moist, round

lump. Muscles in the pharynx swallow the food, pushing it into the esophagus, a muscular tube

that passes food into the stomach. The epiglottis prevents food from entering the trachea, or

windpipe, during swallowing.

Esophagus

The presence of food in the pharynx stimulates swallowing, which squeezes the food into

the esophagus. The esophagus, a muscular tube about 25 cm (10 in) long, passes behind the

trachea and heart and penetrates the diaphragm (muscular

Gastroenteritis is a condition that causes irritation and inflammation of the stomach and intestines (the gastrointestinal tract). An infection may be caused by bacteria or parasites in spoiled food or unclean water. Some foods may irritate your stomach and cause gastroenteritis. Lactose intolerance to dairy products is one example.

Many people who experience the vomiting and diarrhea that develop from these types of infections or irritations think they have "food poisoning," which they may, or call it "stomach flu," although influenza has nothing to do with it.

Travelers to foreign countries may experience "traveler's diarrhea" from contaminated food and unclean water.

The severity of infectious gastroenteritis depends on your immune system’s ability to resist the infection. Electrolytes (these include essential elements of sodium and potassium) may be lost as you vomit and experience diarrhea.

Most people recover easily from a short bout with vomiting and diarrhea by drinking fluids and easing back into a normal diet. But for others, such as babies and the elderly, loss of bodily fluid with gastroenteritis can cause dehydration, which is a life-threatening illness unless the condition is treated and fluids restored.

This Concept Map, created with IHMC CmapTools, has information related to: Acute

Gastroenteritis (lower GI bleed), Decreased coronary blood flow: angina . Myocardial infarction: pulmonary edema, Accumulation of blood in GI tract . Digestion of blood proteins, Compensatory constriction of peripheral arteries . Compensatory failure, Compensatory constriction of peripheral arteries . Metabolic acidosis, Mesenteric insufficiency: abdominal pain . Liver necrosis, Lactic acidosis . Anoxia, Mesenteric insufficiency: abdominal pain . Bowel infarction, Nubain . Mesenteric insufficiency: abdominal pain, Metabolic acidosis . Decreased blood flow to GI structures, Blood volume depletion . Decreased systolic blood pressure, Anoxia . Decreased blood flow to brain anxiety, confusion, stupor, coma, Decreased systolic blood pressure , Compensatory constriction of peripheral arteries, D5 1/2 NS . Blood volume depletion, Risk for constipation/diarrhea r/t inadequate diet/fluid intake . Increased peristalsis and diarrhea, Metabolic acidosis . Lactic acidosis, Acute Gastroenteritis Lower GI Bleed . Blood volume depletion, Decreased blood flow to skin: pallor . Decreased blood flow to kidneys: decreased urine output, Increased: MCV, MCH, and Lymphocytes . Blood volume depletion, Acute Gastroenteritis Lower GI Bleed . Accumulation of blood in GI tract, Risk for decreased cardiac output r/t decreased blood flow to heart muscle . Decreased cardiac output

Gastroenteritis (also known as gastric flu or stomach flu, although unrelated to influenza) is inflammation of the gastrointestinal tract, involving both the stomach and the small intestine and resulting in acute diarrhea. It can be transferred by contact with contaminated food and water. The inflammation is caused most often[citation needed] by an infection from certain viruses or less

often[citation needed] by bacteria, their toxins, parasites, or an adverse reaction to something in the diet or medication. Current death rates have come down significantly to approximately 1.5 million deaths annually in the year 2000, largely due to the global introduction of oral rehydration therapy [1] and is a leading cause of death among infants and children under 5.[2]

At least 50% of cases of gastroenteritis due to foodborne illness are caused by norovirus.[3] Another 20% of cases, and the majority of severe cases in children, are due to rotavirus. Other significant viral agents include adenovirus [4] and astrovirus.

Different species of bacteria can cause gastroenteritis, including Salmonella, Shigella, Staphylococcus, Campylobacter jejuni, Clostridium, Escherichia coli, Yersinia, Vibrio cholerae, and others. Some sources of the infection are improperly prepared food, reheated meat dishes, seafood, dairy, and bakery products. Each organism causes slightly different symptoms but all result in diarrhea. Colitis, inflammation of the large intestine, may also be present.

Risk factors include consumption of improperly prepared foods or contaminated water and travel or residence in areas of poor sanitation. It is also common for river swimmers to become infected during times of rain as a result of contaminated runoff water.[5]

Gastroenteritis Overview

Gastroenteritis is a condition that causes irritation and inflammation of the stomach and intestines (the gastrointestinal tract). An infection may be caused by bacteria or parasites in spoiled food or unclean water. Some foods may irritate your stomach and cause gastroenteritis. Lactose intolerance to dairy products is one example.

Many people who experience the vomiting and diarrhea that develop from these types of infections or irritations think they have "food poisoning," which they may, or call it "stomach flu," although influenza has nothing to do with it.

Travelers to foreign countries may experience "traveler's diarrhea" from contaminated food and unclean water.

The severity of infectious gastroenteritis depends on your immune system’s ability to resist the infection. Electrolytes (these include essential elements of sodium and potassium) may be lost as you vomit and experience diarrhea.

Most people recover easily from a short bout with vomiting and diarrhea by drinking fluids and easing back into a normal diet. But for others, such as babies and the elderly, loss of bodily fluid with gastroenteritis can cause dehydration, which is a life-threatening illness unless the condition is treated and fluids restored.

V. ANATOMY AND PHYSIOLOGY

Anatomy of the Digestive System

If a human adult’s digestive tract were stretched out, it would be 6 to 9 m (20 to 30 ft) long.

In humans, digestion begins in the mouth, where both mechanical and chemical digestion occur. The

mouth quickly converts food into a soft, moist

mass. The muscular tongue pushes the food against the teeth, which cut, chop, and grind the food.

Glands in the cheek linings secrete mucus, which lubricates the food, making it easier to chew and

swallow. Three pairs of glands empty saliva into the mouth through ducts to moisten the food. Saliva

contains the enzyme ptyalin, which begins to hydrolyze (break down) starch—a carbohydrate

manufactured by green plants.Once food has been reduced to a soft mass, it is ready to be swallowed.

The

tongue pushes this mass—called a bolus—to the back of the mouth and into the pharynx. This cavity

between the mouth and windpipe serves as a passageway both for food on its way down the

alimentary canal and for air passing into the windpipe. The epiglottis, a flap of cartilage, covers the

trachea (windpipe) when a person swallows. This action of the epiglottis prevents choking by

directing food from the windpipe and toward the stomach.

MouthThe mouth plays a role in digestion, speech, and breathing. Digestion begins

when food enters the mouth. Teeth break down food and the muscular tongue pushes food back

toward the pharynx, or throat. Three salivary glands—the sublingual gland, the submandibular gland,

and the parotid gland—secrete enzymes that partially digest food into a soft, moist, round lump.

Muscles in the pharynx swallow the food, pushing it into the esophagus, a muscular tube that passes

food into the stomach. The epiglottis prevents food from entering the trachea, or windpipe, during

swallowing.

Esophagus

The presence of food in the pharynx stimulates swallowing, which squeezes the food into the

esophagus. The esophagus, a muscular tube about 25 cm (10 in) long, passes behind the trachea and

heart and penetrates the diaphragm (muscular

wall between the chest and abdomen) before reaching the stomach. Food advances through the

alimentary canal by means of rhythmic muscle contractions (tightenings) known as peristalsis. The

process begins when circular muscles in the esophagus wall contract and relax (widen) one after the

other, squeezing food downward toward the stomach. Food travels the length of the esophagus in two

to three seconds.

A circular muscle called the esophageal sphincter separates the esophagus and the stomach.

As food is swallowed, this muscle relaxes, forming an opening through which the food can pass into

the stomach. Then the muscle contracts, closing the opening to prevent food from moving back into

the esophagus. The esophageal sphincter is the first of several such muscles along the alimentary

canal. These muscles act as valves to regulate the passage of food and keep it from moving

backward.

Stomach

The stomach, located in the upper abdomen just below the diaphragm, is a saclike structure

with strong, muscular walls. The stomach can expand significantly to store all the food from a meal

for both mechanical and chemical processing. The stomach contracts about three times per minute,

churning the food and mixing it with gastric juice. This fluid, secreted by thousands of gastric glands

in the lining of the stomach, consists of water, hydrochloric acid, an enzyme called pepsin, and

mucin (the main component of mucus). Hydrochloric acid creates the acidic

environment that pepsin needs to begin breaking down proteins. It also kills microorganisms that

may have been ingested in the food. Mucin coats the stomach, protecting it from the effects of the

acid and pepsin. About four hours or less after a meal, food processed by the stomach, called chyme,

begins passing a little at a time through the pyloric sphincter into the duodenum, the first portion of

the small intestine.

Liver

The liver is the largest internal organ in the human body, located at the top of the abdomen on

the right side of the body. A dark red organ with a spongy texture, the liver is divided into right and

left lobes by the falciform ligament. The liver performs more than 500 functions, including the

production of a digestive liquid called bile that plays a role in the breakdown of fats in food. Bile

from the liver passes through the hepatic duct into the gallbladder, where it is stored. During

digestion bile passes from the gallbladder through bile ducts to the small intestine, where it breaks

down fatty food so that it can be absorbed into the body. Nutrient- rich blood passes from the small

intestine to the liver, where nutrients are further processed and stored. Deoxygenated blood leaves

the liver via the hepatic vein to return to the heart.

Small Intestine

Most digestion, as well as absorption of digested food, occurs in the small intestine. This

narrow, twisting tube, about 2.5 cm (1 in) in diameter, fills most of the lower abdomen, extending

about 6 m (20 ft) in length. Over a period of three to six hours, peristalsis moves chyme through the

duodenum into the next portion of the small intestine, the jejunum, and finally into the ileum, the last

section of the small intestine. During this time, the liver secretes bile into the small intestine through

the bile duct. Bile breaks large fat globules into small droplets, which enzymes in the small intestine

can act upon. Pancreatic juice, secreted by the pancreas, enters the small intestine through the

pancreatic duct. Pancreatic juice contains enzymes that break down sugars and starches into simple

sugars, fats into fatty acids and glycerol, and proteins into amino acids. Glands in the intestinal walls

secrete additional enzymes that break down starches and complex sugars into nutrients that the

intestine absorbs. Structures called Brunner’s glands secrete mucus to protect the intestinal walls

from the acid effects of digestive juices.

The small intestine’s capacity for absorption is increased by millions of fingerlike

projections called villi, which line the inner walls of the small intestine. Each villus is about 0.5 to

1.5 mm (0.02 to 0.06 in) long and covered with a single layer of cells. Even tinier fingerlike

projections called microvilli cover the cell surfaces. This combination of villi and microvilli

increases the surface area of the small intestine’s lining by about 150 times, multiplying its capacity

for absorption. Beneath the villi’s single layer of cells arecapillaries (tiny vessels) of the bloodstream

and the lymphatic system. These capillaries allow nutrients produced by digestion to travel to the

cells of the body. Simple sugars and amino acids pass through the capillaries to enter the

bloodstream. Fatty acids and glycerol pass through to the lymphatic system.

Large Intestine

A watery residue of indigestible food and digestive juices remains unabsorbed. This residue

leaves the ileum of the small intestine and moves by peristalsis into the large intestine, where it

spends 12 to 24 hours. The large intestine forms an inverted U over the coils of the small intestine. It

starts on the lower right-hand side of the body and ends on the lower left-hand side. The large

intestine is 1.5 to 1.8 m (5 to 6 ft) long and about 6 cm (2.5 in) in diameter.

The large intestine serves several important functions. It absorbs water— about 6 liters (1.6

gallons) daily—as well as dissolved salts from the residue passed on by the small intestine. In

addition, bacteria in the large intestine promote the breakdown of undigested materials and make

several vitamins, notably vitamin K, which the body needs for blood clotting. The large intestine

moves its remaining contents toward the rectum, which makes up the final 15 to 20 cm (6 to 8 in) of

the alimentary canal. The rectum stores the feces—waste material that consists largely of undigested

food, digestive juices, bacteria, and mucus—until elimination. Then, muscle contractions in the walls

of the rectum push the feces toward the anus. When sphincters between the rectum and anus relax,

the feces pass out of the bod