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DIGESTIVE ANATOMY

• Gastrointestinal Tract

• Accessory Organs

FUNCTIONSFUNCTIONS• Food Ingestion• Food Movement• Mechanical Preparation of Food• Chemical Digestion of Food• Absorption of Foodstuffs• Elimination

MICROANATOMYMICROANATOMYLayers of G.I. TractLayers of G.I. Tract

• Tunica Mucosa– Epithelial– Lamina Propria– Muscularis Mucosa

• Tunica Submucosa• Tunica Muscularis• Tunica Serosa

Gastrointestinal Regulation

• Automaticity• Intrinsic nerve plexus• Extrinsic innervation• Hormones

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MOUTH• Chewing• Saliva

– parotid glands– submandibular– sublingual

Functions of Saliva• Digestion

– ptyalin

• Lubrication– mucin

• Solvent

• Oral hygiene

* Xerostomia

ESOPHAGUS• Swallowing Phases• Esophageal hiatus

–hiatal hernia• Pharyngoesophageal

sphincter• Gastroesophageal

sphincter

STOMACH• ANATOMY

–body–fundus–antrumrugae

Stomach Microanatomy• Oxyntic Mucosa

– mucous neck cells

– chief cells

– parietal cells

• Pyloric Gland Area

– gastrin

• Mechanical– storage– mixing– movement

Stomach Digestion

• Chemical– mucous– HCL– pepsin– intrinsic factor

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REGULATION• Cephalic phase

• Gastric phase– gastrin

• Intestinal Phase– enterogastric reflex

– enterogastrones• somatostatin

• gastric inhibitory peptide

SMALL INTESTINE

•Duodenum

•Jejunum

• Ilium

Wall Modifications• Plica Circularis

• Villi

• Microvilli– enterokinase– disaccharidases– aminopeptidases

PANCREATIC AND LIVER SECRETIONS

PANCREAS• Bicarbonate• Enzymes

– Proteases trypsinogen chymotrypsinogen procarboxypeptidase

– Lipases– Amylases– Other

LIVER• Bile Salts

Regulation of Secretions

• Secretin

– response to presence of acid chyme

– induces pancreas to secrete bicarbonate

• Cholecystokinin

– response to presence of foodstuffs; especially fats

– induces pancreas to release enzymes

– induces gall bladder to release bile

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Final Digestion and Absorption in Microvilli

• Fats–chylomicrons

• Carbohydrates

• Proteins

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FUNCTIONS OF LARGE INTESTINE

•Absorption

•Synthesis of Vitamins–Vitamin K

•Movement and Defecation

DEFECATION• Haustral Contractions

• Gastrocolic Reflex

• Internal and External Anal Sphincter

PATHOLOGIES• Ulcers

– gastric– duodenal– Zollinger-Ellison Syn.

• Inflammatory Bowel Disease– Chrone’s Disease– Ulcerative colitis

• Appendicitis– Fecalith

• Diverticulosis

ULCER TREATMENTS• Neutralize

– Aluminum hydroxide (Amphogel)– MgOH plus AlOH (Maalox, Mylanta)

H-2 Blockers• (Zantac)• (Pepcid)• Ulcer Coater (Carafate)• Block H Secretion (Prilosec), (Prevacid)

Antiemetics Emetics• Antihistamines

– (Dramamine)– (Antivert)

• Anticholinergics– (Transderm Scop)

• Central Medullary– (Tigan)– (Zorfran)

• Ipecac Syrup

ANTIDIARRHEALSLOCALLY ACTING

–Kaopectate–Pepto-Bismol

SYSTEMICALLY ACTING

–Opiates (paragoric)–Synthetic Opiates (Lomotil, Imodium)