Digestive System The Gastrointestinal System - PowerPoint Presentation

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Digestive System

The Gastrointestinal System

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Digestive System

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Alimentary Canal

Long, muscular organ that includes the mouth (oral cavity), pharynx, esophagus, stomach, small intestine, large intestine & anus

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Buccal Cavity

Mouth – receives food as it enters the body

Teeth - Food in the mouth is tasted, broken down physically by the teeth, digested, by saliva & swallowed

Mastication – Chewing & grinding of food by the teeth

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Buccal Cavity

Tongue – Muscular organ with special receptors – taste buds

Hard Palate – bony structure that forms the roof of the mouth

Soft Palate – Separates the mouth from the nasopharynx

Uvula – hangs from the soft palate & keeps food from entering the nasopharynx during swallowing

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Buccal Cavity

3 pairs of salivary glands

Parotid

Sublingual

Submandibular

Produce saliva to lubricates the mouth during speech & chewing and moistens food so that it can be swallowed easily

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Salivary Glands

Saliva contains the enzyme salivary amylase (ptyalin)

Begins the chemical breakdown of carbohydrates (starches), into sugars that can be used by the body

Bolus – food that has been chewed & mixed with saliva

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Pharynx

The Throat

A tube that carries the air to the trachea & food to the esophagus

When a bolus is being swallowed muscle action causes the epiglottis to close over the larynx, preventing the bolus from entering the respiratory tract causing it to enter the esophagus

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Esophagus

Muscular tube dorsal to the trachea

Receives the bolus from the pharynx & carries it to the stomach

Relies on a rhythmic, wavelike involuntary movement of its muscles called peristalsis

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Stomach

Enlarged part of the alimentary canal.

Receives food from the esophagus

Rugae – folds inside the stomach

Cardiac Sphincter – between esophagus & stomach

Pyloric sphincter – between stomach & small intestine

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Stomach

Food in stomach 1-4 hours

Chyme – food is converted into a semi-fluid material

Gastric Juices – contain hydrochloric acid & enzymes

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Stomach Enzymes

Hydrochloric Acid – kills bacteria, facilitates iron absorption & activates the enzyme pepsin

Lipase – starts the chemical break down of fats

Pepsin starts protein digestion

Rennin aids in the digestion of milk (found only in children)

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Small Intestine

Coiled section of alimentary canal 20 feet long

Divided into the:

duodenum (9-10 in.) jejunum (8 ft.) ileum (12 feet)

Cecum – place that the small intestine connects to the large intestine.

Ileocecal valves – separates the ileum & cecum

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Small Intestine

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Enzymes in the Small Intestine

Duodenum – Bile (from the gallbladder & liver) and pancreatic juice enter through ducts

Process of digestion is completed in the small intestine

The products of digestion are absorbed into the blood stream for use by body cells

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Small Intestine Enzymes

Maltase, sucrase & lactase break down sugars into simpler forms

Peptidases – completes the digestion of proteins

Steapsin – aids in the digestion of fats

Bile – from liver & gallbladder emulsifies fats

Pancreatic enzymes complete digestion

Pancreatic amylase or amylopsin acts on sugars

Trypsin and chymotrypsin act on proteins

Lipase or steapsin acts on fats

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Absorption

After food is digested it is absorbed into the bloodstream

Walls of small intestine are lined with finger-like projections called villi

Villi contain blood capillaries & lacteals

Blood capillaries absorb the nutrients & carry them to the liver

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Absorption

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Large Intestine

5 ft. in length & 2 in. in diameter

Functions include: absorption of water & remaining nutrients, storage of indigestible materials before elimination

Synthesis of some B complex vitamins & vitamin K

Transportation of waste products from the body

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Large Intestine

Cecum – first section & is connected to the ileum of the small intestine. It contains a small projection called the veriform appendix

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Large Intestine

Colon has several divisions:

Ascending colon – up the right side of body from the cecum to the lower part of the liver

Transverse Colon – Extends across the abdomen, below the liver & stomach and above the small intestine

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Large Intestine

Descending Colon – extends down the left side of the body. Connects with the sigmoid colon

Sigmoid Colon, an S shaped section that joins the rectum

Rectum – final 6 – 8 in. of the large intestine & is a storage area for indigestible & waste

The narrow anal canal opens at a hole called the anus

Fecal material or stool, the final waste product is expelled

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Liver

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Liver

Largest Gland

Secretes Bile which emulsifies fats & makes them water soluble

Stores Sugar in the form of glycogen

Stores Iron & Vitamins

Produces heparin, fibrinogen, prothrombin & Cholesteral

Detoxifies substances

Destroys bacteria taken into the blood from the intestine

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Liver

Heparin: Prevents clotting

Fibrinogen: Blood Protein aids in clotting

Prothrombin: Blood Protein aids in clotting

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Gallbladder

Small, muscular sac located under liver

Stores & concentrates bile

Bile needed to emulsify fats

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Pancreas

Glandular organ

Produces pancreatic juices & enzymes

Produces insulin

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Diseases

Appendicitis

– Acute inflammation or infections of the appendix

Symptoms: RLQ abdominal pain, nausea/vomting, mild fever, elevated WBC.

Danger- peritonitis

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Diseases

Cholecystitis- inflammation of the gallbladder, characterized by formation of cholelithiasis (gallstones, which are crystallized cholesterol, bile salts, and bile pigments)

Symptoms- pain under the rib cage radiating to the right shoulder, indigestion, n/v occurs after eating fatty meal.

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continued

Cholecystitis

- if a gallstone blocks the bile duct, it can rupture causing peritonitis

Treatment-low fat diet, lithotripsy, and possible cholecystectomy

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Diseases

Constipation

-when fecal material stays in the large intestine too long causing excessive reabsorption of water. Stool becomes hard, dry, and difficult to eliminate.

Causes- low fiber diet; chronic laxative use makes the bowel “lazy”

Treatment- high fiber diet; fluids, and exercise (avoid laxatives if possible)

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Diseases

Diarrhea-

frequent water stools caused by infection, stress, diet, irritated colon, or toxic substances. Can be dangerous in infants and small children.

Treatment is directed at eliminating the cause, modifying diet, and adequate fluids.

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Diseases

Diverticulitis

- inflammation of the diverticula (sacs) that form in the lining of the intestine. Occurs when fecal material or bacteria become trapped in the “sacs”. Can result in abscess or rupture and cause peritonitis.

Symptoms- abdominal pain, gas, abdominal distention, constipation, diarrhea

Treatment-antibx, pain med, surgery

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Diseases

Gastroenteritis-

inflammation of the mucosal membrane lining the GI tract.

Cause-food poisoning, infection, toxins

Symptoms- abdominal cramping, n/v, diarrhea

Treatment- replace fluids, rest, antibiotics, IV fluids if severe.

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Diseases

Hemorrhoids

- painful dilated or varicose veins of the rectum or anus.

Symptoms- pain, itching, bleeding

Treatment- high fiber diet, stool softeners, sitz baths, warm moist compresses.

If severe, hemorrhoidectomy.

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Diseases

Hepatitis

- inflammation of the liver

A- infectious hepatitis- transmitted in food or water that has been contaminated by feces of an infected person. Most benign type.

B- transmitted by all body fluids including breast milk, saliva, and urine. (vaccine)

C- also transmitted through blood and body fluids but more likely to cause cirrhosis.

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Hepatitis continued

C-no vaccine

Symptoms- fever, fatigue, anorexia, n/v, mylagia, dark urine, clay colored stool, enlarged liver and jaundice.

Treatment- rest, diet high in protein and calories but low in fat. If severe, liver transplant.

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Diseases

Hernia

- a rupture that occurs when an internal organ pushes through a weakening or natural opening in a body wall.

hiatal hernia- when the stomach protrudes through the diaphragm into the chest cavity through the opening for the esophagus.

If a hernia cannot be reduced, then a herniorraphy is performed.

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Diseases

Ulcer

– open sore on the lining of the digestive tract. Peptic ulcers include stomach and duodenal ulcers.

Causes- H. pylori bacteria is most common cause (infection) by burrowing into the lining allowing gastric juices to create an ulcer.

Symptoms- burning pain, indigestion, melena, and hematemesis.

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Ulcers cont.

Treatment- bland diet, decreased stress, avoiding irritants. Bismuth medications (pepto bismol is used) If H. Pylori is the cause, this is an infection that should be treated with antibiotics.

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Diseases

GERD (gastroesophageal reflux disease

)- occurs when stomach contents and acid leak back into the esophagus and there are visible signs of irritation to the lining of the esophagus. Many people have acid reflux, heartburn, and indigestion but that doesn’t mean they have GERD.

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GERD cont.

Symptoms- burning pain in your lower chest, tasting acid in your mouth, throat.

Treatment- dietary and lifestyle changes; avoiding irritation to the esophagus (chocolate, peppermint, alcohol, fatty foods, coffee, citrus fruits and juices)

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