Health Occupations

Digestive System

Digestive/Gastrointestinal System Consists of organs making up ALIMENTARY

CANAL– From mouth to anus– 30 feet long– Not a sterile system – open to environment at both ends– Process includes

• Transportation of food & wastes• Physical & chemical breakdown of food• Absorption of digested food• Elimination of wastes• Helps to maintain proper amounts of water, nutrients, electrolytes

Definitions

Digestion– Process of changing food into a usable

substance Absorption

– Transfer of nutrients into the blood

Organs of the Digestive System1. Mouth

A. Food enters alimentary canal – INGESTIONB. Teeth – bite & chew food to physically break it downC. Tongue – tastes, chews (MASTICATION), & helps swallow (DEGLUTITION)D. Hard palate – anterior roof of mouthE. Soft palate – posterior roof of mouth, not attached to bone

F. Uvula – small piece of tissue at back to mouth to prevent food from entering nasal cavity during chewingG. Process of mastication1. As food is chewed – mixes with saliva2. 3 salivary glands – secrete amylase to begin chemical breakdown of food (enzyme – protein that increases therate of chemical activity in body)a. Parotidb. Sublingualc. Submandibular

H. Begins the transformation of starch to sugarI. Bolus – portion of food, mixed with saliva, that is swallowed

2. Pharynx – 3 parts – nasopharnyx, oropharynx, laryngopharynxA. Food passes through oropharynx from mouth to esophagusB. Epiglottis closes so you don’t inhale food/drink

3. EsophagusA. Tube like structure carrying food from mouth to stomachB. Peristalsis – movement of food down esophagus with slow, wavelike movements

4. StomachA. Bolus mixes with HCL & enzymes pepsin & lipase to become CHYME (semifluid material)1. Pepsin – starts protein digestion2. Lipase – starts fat digestion3. HCL – kills bacteria, helps iron absorption, activates pepsin4. Rennin – in infants, helps milk digestion, not present in adults5. Direct absorption – alcohol, glucose,some drugs via stomach walls

6. Cardiac sphincter – valve preventing chyme from flowing backinto esophagus7. Pyloric sphincter – controls flowof chyme into intestines. Takes 1-4hours for stomach to empty into intestines

5. Small Intestine

A. Coiled section about 20 feet long, 1 inch in diameter

B. 3 sections1. Duodenum – 1st 9-10 inches where bile from gall bladder & liver & pancreatic juices enter through ducts2. Jejunum – 8 feet in length, middle section3. Ileum – final 12 feet, connects with large intestine at cecum

IleumA. Ileocecal valve – separates ileum & cecum,

prevents food from returning to ileumB. Digestion completed in small intestine, products are

absorbed into bloodstreamC. Intestinal juices produced by small intestine,

contains enzymes that break down sugars into simple forms (maltase, sucrase, lactase)

D. Also has pepsidases – protein digestionE. Steapsin – aids in fat digestionF. Bile – from liver & gall bladder to physically break

down fats

IleumG. Pancreatic enzymes – complete process of breaking

down food1. Pancreatic amylase – sugar2. Trypsin/chymotrypsin – proteins3. Lipase/steapsin – fats

H. Villi – small fingerlike projections lining walls of small intestine – contain capillaries & lacteals

1. Capillaries – absorb nutrients & carry to liver for storage or released into circulation

2. Lacteals – absorb fat & carry to thoracic duct of lymph system to be released into circulation

I. Only wastes, indigestibles, & water are left

6. Large Intestine

A. Final section, 5 feet in length, 2 inches in diameter

B. Functions1. Absorb water & other nutrients2. Stores indigestible materials before elimination3. Synthesizes & absorbs B vitamins & Vitamin K

by bacteria4. Transports wastes out

C. Divided into a series of connected sections

1. Cecum – 1st section, connected to ileum, contains appendix2. Colon – 4 partsa. Ascending – up right side of bodyto lower liverb. Transverse – across abd below liver & stomach, above sm intestinec. Descending – down left side of bodyd. Sigmoid – S shaped section, joins with rectum

e. Rectum – final 6 – 8 inches, stores wastes & indigestiblesf. Anal canal – narrow canal at

end, opening into anus where wastes

areexpelled through

7. Peritoneum

A. Flat serous membrane surrounding abdominal cavity

B. Lubricates & prevents friction between organs

C. Mesentary – fan-shaped projection of peritoneum that contains blood vessels & nerves

1. binds to abdominal organs to keep them in place

8. Accessary Organs

A. Liver – largest gland in body1. Located under diaphragm in RUQ2. Secretes bile – emulsify fats & makes them water

soluble to be absorbed3. Stores sugar – glycogen, converts to glucose &

released to bloodstream when extra sugar is needed4. Stores iron & vitamins5. Produces heparin, fibrinogen, & prothrombin –

prevent clotting of blood6. Detoxifies substances like alcohol & pesticides7. Destroys bacteria taken into blood by intestine

B. Gallbladder

1. Small muscular sac located under liver, attached by connective tissue

2. Stores & concentrates bile (receives from liver)

3. Contracts when bile is needed to emulsify fats, bile goes through the common bile duct & into duodenum

C. Pancreas

1. Gland located behind stomach2. Produces pancreatic juices – contain

enzymes to digest food3. Pancreatic juices enter duodenum

through pancreatic duct4. Produces insulin which regulates

metabolism, burning of carbs to convert glucose to energy

Parotid glandEsophagusCardiac sphincterStomachPancreasTransverse colonDescending colonSigmoid colonRectumAnus

AppendixCecumIleum

Ascending colonDuodenum

Pyloric sphincterGall bladderLiverLarynxPharynx

Appendicitis

Acute inflammation of appendix, usually from obstruction & infection

Symptoms– Generalized abd pain, later localizing in RLQ– N & V– Mild fever– Elevated WBC

If ruptures, infectious material spills into peritoneum & causes peritonitis

TX - appendectomy

Cholecystitis

Inflammation of gallbladder where gallstones form (cholelithiasis)

Symptoms occur after fatty meal– Indigestion, N & V– Pain under ribcage, radiates to right shoulder

If gallstones block bile ducts, gallbladder can rupture

Tx – low fat diet, lithotripsy, cholecystectomy

Cirrhosis Chronic destruction of liver cells with formation of fibrous

connective & scar tissue Causes –

– Hepatitis– Bile duct disease– Chemical toxins– Malnutrition associated with alcoholism

Symptoms– Liver enlargement– Anemia– Indigestion, N & V– Nosebleeds– Jaundice– Ascites

Cirrhosis

Tx –– Prevent more damage to liver– Avoid alcohol– Good nutrition– Supplements– Rest– Infection prevention– Appropriate exercise

Constipation Fecal material remains in colon too long Causes excessive reabsorption of water Stool – hard, dry, difficult to eliminate Causes –

– Poor bowel habits– Chronic laxative use– Low fiber diet– Digestive diseases

TX– High fiber diet– Adequate fluids & exercise– Occasional laxatives

Diarrhea Condition with frequent watery stools Causes

– Infection– Stress– Diet– Irritated colon– Toxic substances– Very dangerous in young

Tx– Eliminating cause– Adequate fluids– Modifying diet

Diverticulitis Inflammation of diverticula (pouches that form in intestine

as mucosal lining pushes through surrounding muscle) Fecal material & bacteria become trapped in diverticula,

creating inflammation Result – abscess formation or rupture Symptoms – vary with level of inflammation

– Abd pain, N & V– Irregular BM– Flatus, constipation, diarrhea– Abd distension– Low grade fever

Diverticulitis

Tx– Antibiotics– Stool softeners– Pain meds– surgery

Gastroenteritis Inflammation of mucous membrane lining stomach & intestine Causes

– Food poisoning– Infection– toxins

Sx– Abd cramping, N & V– Fever & diarrhea

Tx– Rest, fluids– Antibiotics, IV– Meds to slow peristalsis

Hemorrhoids

Painful, dilated or varicose veins of rectum or anus

Causes – – Straining to defecate– Constipation– Pressure during pregnancy– Insufficient fluids– Laxative abuse– Prolonged sitting or standing

Hemorrhoids

Sx– Pain– Itching– bleeding

Tx– High fiber diet– Increased fluids– Stool softeners– Sitz baths or warm moist compresses– hemorrhoidectomy

Hepatitis

Viral inflammation of liver– Type A – highly contagious, transmitted in food or

water contaminated by feces of infected person, vaccine available

– Type B – transmitted by blood, can lead to chronic hepatitis or cirrhosis, vaccine available

– Other strains– SX – fever, anorexia, N & V, fatigue, dark colored

urine, clay-colored stools, enlarged liver, jaundice– TX – rest, diet high in protein & calories but low in

fat, may need liver transplant

Hernia

Rupture, occurring when internal organ pushes through a weakened area or natural opening in a body wall

Hiatal hernia – stomach protrudes through diaphragm into chest cavity or esophagus – see heartburn, abd distention, chest pain, difficult swallowing– Tx – bland diet, small freq meals, staying upright

after meals, surgery

Inguinal hernia

Protrudes through lower abd wall Sometimes can be reduced (pushed

back into place) Surgery

Pancreatitis

Inflammation of pancreas where pancreatic enzymes begin to digest the pancreas itself

Pancreas becomes necrotic, inflamed, & edematous

Can lead to shock & hemorrhage if it extends into blood vessels

Causes – excessive alcohol– Gallstones– idiopathic

Pancreatitis

Sx –– Severe abd pain radiating to back– N & V– Diaphoresis– jaundice

Tx– Depends on cause– Pain control– Nutritional support– Surgery

Peritonitis

Inflammation of peritoneal cavity Usually occurs when intestine ruptures

& allows contents to enter peritoneum Common cause – ruptured appendix or

gallbladder Sx – abd pain, distension, N & V, fever Tx – antibiotics, surgical repair

Ulcer

Open sore on lining of digestive tract May be gastric (stomach) or intestinal

(Duodenal) H. Pylori – bacteria that burrows into stomach

membranes and allow acids & digestive juices to create an ulcer

Sx– Burning pain, indigestion– Hematemesis– Melena

Ulcer

TX– Antacids– Bland diet– Decreased stress– Avoid irritants (alcohol, fried foods, tobacco,

caffeine)– With H.Pylori – give antibiotics & Pepto-Bismol– Severe - surgery

Ulcerative colitis

Severe inflammation of colon accompanied by formation of ulcers & abscesses

Causes – stress, food allergy, autoimmune Sx – bloody diarrhea

– Pus, mucous– Weight loss– Weakness– Abd pain, anorexia– Anemia

Periods of remission & exacerbation

Ulcerative colitis

Tx – Control inflammation– Reduce stress– Good nutrition– Avoid irritants– May need surgery & colostomy

Alactasia

Lactose intolerance Don’t produce enough lactase & so

unabsorbed lactose ferments in intestines – gas, cramps, diarrhea

Tx – decrease dairy intake or take lactase supplements

Food poisoning

Common, includes 300 illnesses transmitted by food (I.e. salmonella, listeria)

Sx – HA– Unrelenting diarrhea– N & V– Fever

Tx - antibiotics

Mumps

Viral infection of parotid glands Most common in 5 – 15 year olds Parotids painfully swell Can damage reproductive organs if

older Treat symptoms, no cure, runs its

course

Phenylketonuria

PKU Inherited disease that can lead to mental

retardation if untreated 1/8000 babies Causes abn metabolism of proteins SX – irritability in infant, restless, eventually

leads to convulsions TX – diet modification & routine blood work All babies are tested

Pyloric stenosis

Constricted pyloric sphincter Doesn’t allow food to easily pass into

small intestine 1/4000 infants Sx – projectile vomiting, diarrhea,

dehydration, weight loss TX - surgery