Structure/ Regulation of GI Tract

Question 1

What structures does the GI tract include?

Answer 1

Oral cavity, esophagus, stomach, small and large intestines

Question 2

What is the term for stomach?

Answer 2

Gastric

Question 3

What is the term for intestines?

Answer 3

Enteric

Question 4

What 4 layers of tissue does the does the GI tract wall consist of?

Answer 4

From the lumen outwards - mucosa, submucosa, circular and longitudinal muscular layers, and serosa

Question 5

What three parts does the mucosa in the GI tract consist of?

Answer 5

Epithelium, lamina propria, muscularis mucosae

Question 6

What types of epithelial tissue does the GI tract consist of?

Answer 6

Mouth/ anus - stratified squamous epithelium
Rest of GI tract - simple columnar epithelium

Question 7

What type of junctions connect the epithelial cells in the GI tract?

Answer 7

Tight junctions

Question 8

What type of tissue does the lamina propria consist of?

Answer 8

Loose areolar connective tissue

Question 9

What structures does the lamina propria layer contain?

Answer 9

Blood, lymph vessels, glands

Question 10

What type of muscle does the muscularis mucosae in the GI tract consist of and what does it do?

Answer 10

Smooth muscle - forms the mucosa folds that increase the surface area of the lining of the stomach and intestines

Question 11

What type of tissue does the submucosa layer consist of?

Answer 11

Dense connective tissue

Question 12

What are the two smooth muscle layers in the GI tract?

Answer 12

Inner circular and outer longitudinal

Question 13

What type of tissue is the serosae layer made up of?

Answer 13

Loose connective tissue

Question 14

The part of the process where large molecules are broken down into their smaller components

Answer 14

Digestion

Question 15

What are the two control systems the GI tract is regulated by?

Answer 15

1. CNS and endocrine system
2. Enteric nervous system with intrinsic endocrine/ paracrine component

Question 16

The enteric nervous system is commonly known as what?

Answer 16

The brain of the gut

Question 17

What does the enteric nervous system control?

Answer 17

Secretory and motor functions - contains its own pacemaker cells

Question 18

What 2 plexuses make up the enteric nervous system and what do they do?

Answer 18

1. Submucosal plexus - controls secretions and blood flow
2. Myenteric plexus - controls movement of GI tract through local reflexes

Question 19

What is the difference between endocrine and paracrine cells?

Answer 19

Endocrine cells secrete hormones directly into the bloodstream, paracrine cells secrete substances into interstitial fluid which travel by diffusion and affect neighboring cells

Question 20

What does the endocrine hormone cholecystokinin do?

Answer 20

Inhibits gastric emptying