Intestines

Question 1

Jejunum

Answer 1

between ileum and duodenum
larger lumen than ileum
absorption of nutrients

Question 2

Ileum

Answer 2

The longest section of small intestine, posterior portion
terminates at ileocecal valve
Peyer’s Patches (MALT) fight infections

Question 3

Structural Modifications of Small Intestine

Answer 3

• Plicae circulares
• villi
• microvilli

Question 4

Plicae circulares

Answer 4

Circular folds
-deep folds of mucosa and submucosa ->chyme
spirals through and mixes with enzymes

Question 5

Villi`

Answer 5

(finger like) projections of mucosa (simple columnar epithelial cells)
-anchored to lamina propria (blood and lymphatic vessels)
-Intestinal Crypts: narrow pouches between villi, H2O + mucous
-deep in crypts= paneth cells=lysozyme

Question 6

Microvilli

Answer 6

Hair like projections of cell membrane of villi= brush border= enzymes for protein, sugar, and carbohydrate digestion

Question 7

Function of Small Intestine

Answer 7

Digestion
Absorption: monosaccharides, amino acids, h2o, lipids, vitamins, electrolytes

Question 8

Large Intestine

Answer 8

Extends from ileocecal valve to anus
Served by Superior Mesenteric Artery
4 Regions
- cecum
-colon
-rectum
-anal canal

Question 9

Cecum

Answer 9

1st region of large intestine, sac like part beneath ileocecal valve, appendix hands from medial surface in lower right quadrant
-MALT: traps enteric bacteria= infection=appendicitis

Question 10

3 major regions where the portal system and the systemic venous system meet

Answer 10

esophagus, umbilicus, rectum

Question 11

Colon

Answer 11

Ascending Colon: right side of abdominal cavity, makes 90 degree turn under liver= hepatic flexure
Transverse Colon: horizontal across abdominal cavity, turns down under spleen= splenic flexure
Descending Colon: down left side of abdominal cavity
Sigmoid Colon: s-shaped portion in pelvic cavity

Question 12

Rectal Region/ Rectum

Answer 12

Continuous with sigmoid colon. Stores feces. Rectal valves- transverse folds separate feces from flatus (intestinal gas), colonic bacteria produces flatus from indigestible carbs (beans, brocolli). Stretching rectal walls initiates defecation

Question 13

Anal Region/ Anal Canal

Answer 13

Opens to exterior via anus. Lines with stratified squamous epithelium
2 Anal Sphincters:
- internal anal sphincter: involuntary (smooth m)
- external anal sphincter: voluntary (skeletal muscle)

Question 14

Hemorrhoids

Answer 14

External Hemorrhoids: below the dentate line, more painful
Internal Hemorrhoids: above dentate line, less painful
Mixed Hemorrhoids: above and below dentate line

Question 15

Structural Modifications of Large Intestine

Answer 15

-Muscularis Externa
-Haustra
-Epiploic Appendages

Question 16

Muscularis Externa (LI)

Answer 16

Teniae Coli= 3 bands of smooth muscle. produce powerful and long lasting peristalsis that moves large quantities of chyme to rectum (3x/day)

Question 17

Haustra

Answer 17

Sac like pouches of colon wall
Haustra Cx: Slow segmentation of chyme (every 30 min)= mix, churn, and absorb water and electrolytes from chyme

Question 18

Epiploic Appendages

Answer 18

Fat filled bags hanging from serosa
unknown function

Question 19

Functions of Large Intestine

Answer 19

Formation of feces from indigestible materials
Absorption of Vit K, Vit B and 1800ml of H2O/day (200ml h2o in feces)