1. Small and Large Intestines

3. Small Intestines: General Structure
Extends from pyloric sphincter to ileocecal valve
3 Parts
Duodenum
Fixed in position; low absorption
Receives enzymes from accessory organs
Jejunum
Ileum

4. Special Features
Villi, Microvilli, Plicae circularis – Increase Surface area
Lacteal  lymphatic capillary
Intestinal Glands
Water to aid absorption; no dig. enzymes
Brunner’s Glands  Mucus
Alkaline; duodenum near stomach
Enzymes embedded in mucosal lining
Peptidases – proteins
Sucrase, maltase, lactase  sugars
Intestinal lipase

5. Large Intestines: General Structure
Ileocecal Sphincter
Cecum – Pouchlike proximal end
Appendix – lymphatic tissue; appendectomy
Colon – Ascending, Transverse, Descending, Sigmoid
Hepatic & splenic flexures
Rectum
Anal Canal
Internal anal sphincter (involuntary)
External Anal Sphincter (voluntary)

6. Large Intestines: Functions
Teniae Coli – bands of muscle that extend length of colon
Haustra
Mucus only significant secretion
Formation of feces – indigestible material
Absorption of water & electrolytes
Peristalic rush – rapid contractions of sm. Intestines  diarrhea
Intestinal Flora – bacteria
Cellulose breakdown  Vitamin K, B12, thiamin & riboflavin
Flatulance