Lecture 1 - GIT Structure & Fxn

Question 1

What are the 7 components of the GIT?

Answer 1

1. mouth
2. pharynx
3. esophagus
4. forestomach (rumen, reticulum, omasum) - some animals
5. stomach (abomasum)
6. small intestine (duodenum, jejunum, ileum)
7. cecum and large intestine

Question 2

What are the 6 accessory organs of the GIT?

Answer 2

1. teeth
2. tongue
3. salivary glands
4. liver
5. gall bladder
6. pancreas

Question 3

4 main layers of the small intestine

Answer 3

1. mucosa
2. submucosa
3. muscularis externa
4. serosa

Question 4

5 cell types of the epithelium of the mucosa

Answer 4

1. enterocyte
2. goblet
3. enteroendocrine
4. paneth
5. intestinal stem cells

Question 5

Enterocyte cells

Answer 5

absorption

Question 6

Goblet cells

Answer 6

secrete mucous to keep microbes at bay

Question 7

Enteroendocrine cells

Answer 7

release hormones into blood circulation to communicate locally and systemically

Question 8

Paneth cells

Answer 8

• at crypt base
• secrete antimicrobial molecules to provide host defense against gut microbes

Question 9

Intestinal stem cells

Answer 9

• cell replacement; give rise to other 4 mucosa epithelium cells

Question 10

What does the submucosa contain?

Answer 10

• nerves
• glands

Question 11

What does the muscularis externa contain?

Answer 11

• nerves
• muscles

Question 12

What does the serosa contain

Answer 12

connective tissue

Question 13

What do the microvilli of the epithelial cells (found in mucosa layer) do?

Answer 13

• increase SA/absorptive surface x20

Question 14

What are the tight junction proteins? Where are tight junctions found?

Answer 14

• occludin, claudin, zona occludin create barrier to keep harmful agents out
• found btw enterocytes and goblet cells