1. Small Intestine A. Structure 1. Description and Function
2. Divisions
Duodenum-
Tubular organ extending from the pyloric
sphincter to the beginning of the large intestine.
(20 ft. long in cadaver). Held in place by mesentery which supplies blood to intestines.
Function-final breakdown of food, mixes chyme and
absorption
10 inches long from pylorus to jejunum. It is the
shortest, most fixed portion. No mesentery.
Opening for common bile duct and pancreatic
duct.

2. b) Jejunum-
c) Ileum
8-10 feet long.
2/5 of intestines. Most absorption. Connects to ileum.
12 feet long.
3/5 of intestines. Continues absorption. Ends at ileocecal valve on right side.

4. 3. Layers (outside to inside)
a) Serous Layer-
b) Longitudinal Muscle-
c) Circular Muscle-
d) Submucosa-
e) Mucosa-
Outer epithelial tissue connecting to mesentery and
then posterior of abdomen.
Shortens in length. Churns food
and performs peristalsis.
Constricts diameter. Churns food
and performs peristalsis.
Connective tissue holding mucosa to muscle.
Contains villi for absorption and glands for fluids.

6. 4. Intestinal Mucosa
Columnar cells
Lacteal
Villus
Capillaries
Intestinal gland
(Crypt of Lieberkuhn)
Goblet cells
Arteriole
Venule
Lymph vessel

9. Circular Folds-
Columnar Cells-
Goblet Cells-
Crypts of Lieberkuhn-
Capillary Network-
Lacteal-
Fold of mucosa. Increase surface area (like rugae).
Absorbing cells of villi.
Secrete mucous.
(Intestinal gland) Secretes enzymes.
Absorbs water, glucose and amino acids.
goes to portal vein.
Absorbs fatty acids and glycerol.

10. 4. Intestinal Mucosa
Columnar cells
Lacteal
Villus
Capillaries
Intestinal gland
(Crypt of Lieberkuhn)
Goblet cells
Arteriole
Venule
Lymph vessel

11. B. Secretions
1. Enterokinase-
2. Peptidase-
3. Carbohydrases
Activates trypsinogen from pancreas.
Peptides => amino acids
Complex sugar Glucose and other simple sugars.

12. C. Intestinal Movements
1. Segmentation
2. Pendular-
3. Peristalsis-
Circular muscle constricts (mixes chyme).
Moves chyme back and forth.
Moves chyme forward.
- 1 cm/minute.

13. List, in sequence, the organs from the stomach to
the anus and give the functions of each re:
digestion. (Include secretions & functions.)

16. IV. Large Intestine
A. Structure
Description and Functions-
Approx. 4 1/2 - 5 feet long.
- 2 1/2 inches tapering to 1 inch in diameter.
- connects to ileum and anus/ pouch-like sections
secrete mucous.
Functions: to absorb water and minerals
- bacteria produce vitamins
- forms and stores feces

17. 2. Divisions-
a). Cecum-
b). Appendix-
c). Colon
1. Ascending-
Dead-end pouch.
- 2-3 inches below ileocecal valve.
- 8 cm long/ as wide as the little finger.
Located in lower right quadrant
Right side up to liver (turns at Hepatic flexure).

20. 2. Transverse-
3. Descending-
4. Sigmoid-
From right to left (turns at Splenic flexure).
From left upper abdomen to iliac crest.
S-shaped section of colon
End of descending colon to rectum.

21. 5. Rectum-
6. Anal Canal-
5-6 inches from sigmoid colon to anal canal (store waste)
End of large intestine 11/2 inches from rectum
to anus- internal sphincter = smooth
external sphincter = skeletal

22. 3. Special Features
a). Tenia Coli-
b). Haustra-
No villi/ no enzymes/secretes mucous
(muscle)
- 3 bundles of longitudinal muscle
that are shorter than intestines, causes
pouches
Pouches caused by tenia coli

23. c). Circular Muscles-
4. Activity
a). Movement-
-thicker in anal canal
Mass peristalsis following meals 2-3
times a day, some churning to absorb water

24. b). Bacterial-
c). Fecal Material-
d). Defecation-
-Synthesize Vit. K
-Decomposes undigested material but produces gas and acid
-appear after birth
Water, mucous, bacteria, bile, cellulose + epithelial
cells
Stretch receptors in rectum tell you when it is time
(constipation v. diarrhea)