DIGESTIVE SYSTEM Chapter 3

Digestion is the mechanical and chemical breaking down of food into smaller components, to a form that can be absorbed, for instance, into a blood stream. Digestion is a form of catabolism; a break-down of macro food molecules to smaller ones. componentsabsorbedblood streamcatabolism

Responsible for the intake, digestion of food, absorption of nutrients, and elimination of solid waste. Alimentary Canal (GI tract) Aliment/o - to nourish Anatomy/Physiology

Accessory Digestive Organs Teeth tongue salivary glands liver gallbladder pancreas

Oral Cavity Mouth (bucca, tongue) – papillae Teeth Mastication – dentin – pulp – gingiva

Teeth Maxillary arch (upper) Mandibular arch (lower) – anterior teeth for biting and tearing – posterior teeth for chewing and grinding dent/i - teeth decidu/o - shedding Primary - 20 teeth Permanent - 32 teeth

Oral Cavity Palate, hard and soft – bolus Pharynx Uvula Esophagus Epiglottis

Esophagus Gullet chyme cardiac, or lower esophageal or gastroesophageal sphincter

Stomach Body, fundus pylorus rugae pyloric sphincter Fundus Body

Small Intestine small bowel enter/o - small intestine villi Parts – duodenum – jejunum – ileum ileocecal valve

Large Intestine Large Bowel col/o or colon/o cecum vermiform appendix

Colon – ascending – hepatic flexure – transverse – splenic flexure – descending Sigmoid Rectum Anus

Functions – production of bile – glucose - glycogen – storage of vitamins, B12, A, D, E, K – erythrocytolysis (pigment released eliminated in bile called bilirubin) – bilirubin gives stool its characteristic dark color – removes toxins from blood – manufactures blood proteins Liver - hepat/o

Pancreas internal - endocrine function – insulin – glucogon external - exocrine function – amylase - carbohydrates – trypsin, chymotrypsin - proteins – lipase - fats enzymes inactive until reach duodenum

Gallbladder pear-shaped sac under the liver chol/e means bile or gall cyst/o means cyst or sac gallbladder contracts forcing bile out cystic duct into common bile duct.

Bile bile is a digestive juice- emulsifier acts on fat in a way that lipid enzymes can digest fat travels via hepatic duct to cystic duct to gall bladder, where stored bile consists of water, bile salts, cholesterol, and bilirubin (a colored substance resulting from breakdown of hemoglobin) bilirubin gives bile yellow or orange color

Stomach during Digestion Gastric juices – HCL - activates enzymes – protease – pepsin – lipase Chyme

Small Intestine during Digestion digestion completed in small intestine chyme mixed with bile and pancreatic juices emulsification absorption

Large Intestine receive fluid waste products and store until released from body. excess water absorbed feces, stools defecation, or bowel movement