DIGESTION “You are what you eat.” Malnutrition --------- Obesity Bulimia, Anorexia Nervosa Nutrition : process in which the body takes in and utilizes necessary food substances Nutrients (6): Carbohydrates: quick energy ; sugars and starches; mono, di, polysccharides Lipids : fats; for stored energy ; necessary for the cell membrane Proteins : for maintenance and repair ; made of amino acids

Digestion: the breakdown of food Vitamins: Act as co-enzymes ; A, C, D, etc. Minerals: Aid in metabolism ; Ca, K, Na, etc. Water: Aid in chemical reactions Calories: units of heat that “burn up” food Digestion: the breakdown of food Mechanical Chemical Alimentary Canal : a muscular hollow tube from mouth to anus (9 meters long) Peristalsis

Tongue (with taste buds) MOUTH: Lips Hard palate Soft Palate Uvula Tongue (with taste buds) Teeth (32 secondary): molars, incisors, bicuspids Crown Root Cementum Enamel Dentin

Salivary Glands (3 types) Contain saliva With water and mucus Softens food (Bolus) With salivary amylase or ptylin (digests carbohydrates) Pharynx: opening at back of mouth Esophagus (10 inches –10 minutes) Tube from the mouth to the stomach Behind the trachea No enzymes

J shaped organ on the upper left side Food remains there for 4 hours STOMACH: J shaped organ on the upper left side Food remains there for 4 hours Muscles called rugae Gastric Juices (include acids and enzymes) Pepsin (changes proteins into amino acids) Renin (curdles milk) HCl (kills bacteria) Liquified food called chyme Irritation in top portion of stomach: heartburn Open sore in stomach lining: ulcer

Digested food remains there for 10-12 hours Necessary for life SMALL INTESTINE: Consists of 3 parts: duodenum (10”), jejunum (8 ft.), ileum(12 ft) = 21 ft. long Digested food remains there for 10-12 hours Necessary for life Function: absorption Contains microscopic villi Structure of villi increases surface area With capillaries and lacteals Enzymes released: Sucrase, Lactase, Maltase

Pancreas: releases lipase (fats) and trypsin (proteins) ACCESSORY ORGANS: Pancreas: releases lipase (fats) and trypsin (proteins) Behind the stomach Liver: releases bile (green) Largest organ in the body No enzymes Emulsification: physical breakdown of fats Gall Bladder : stores bile Hardened bile: gall stones

LARGE INTESTINE: Also known as the colon; 4-5 ft. long; tubing with wider diameter than the small intestine Ileocecal Valve: connects to the small intestine Function: reabsorbs water; prevents dehydration Haustra: pouches in the walls of the colon 3 parts: ascending colon, transverse colon, descending colon Appendix: no known digestive function; lymphatic tissue Rectum: muscle that pushes waste out of the anus Internal/External Sphincters regulates defecation Mass Movement (Defecation) Feces: 75% H2O; bilirubin, biliverdin; bacteria (odor)

Digestive Conditions Ulcers (open sores in the stomach due to HCl) Heartburn (irritation in the top of the stomach) Appendicitis (inflammation of the appendix) Colitis (a “nervous stomach”; colon swollen) Diverticulosis (food caught in the pouches of the colon) Cirrhosis of the Liver (liver gets dried out) Jaundice (bile ducts blocked) Hepatitis (inflammation of the liver) Gall Stones (hardened bile) Hemorrhoids (rectal blood vessels inflamed) Constipation (too much water reabsorbed) Diarrhea (too little water reabsorbed)

Digestive Conditions

Dissection of the Earthworm: Phylum Annelid (earthworm) Hermaphrodite: animal with male and female parts Food: dirt, dead leaves, insects Used by farmers: fertilize soil, create air spaces Setae (bristles): on the ventral side of the body for movement Clitellum: contains both male and female parts Mouth, Pharynx, Esophagus Crop: stores food (acts like a stomach) Gizzard: grinds the food