20: Upper Digestive

Question 1

Where does the GI tract begin and end?

Answer 1

Begins at the mouth, ends at the anus

Question 2

What is peristalsis?

Answer 2

Involuntary muscle contractions that propel food through the GI tract

Question 3

What two types of mechanical digestion happen after ingestion?

Answer 3

Churning in the stomach

Segmentation in the small intestine

Question 4

What are the four layers of the GI tract, from deep to superficial?

Answer 4

mucosa, submucosa, muscularis, and serosa or adventitia

Question 5

What is the histological difference between the mucosa of the mouth, pharynx, and anal canal and the mucosa of the stomach and intestines?

Answer 5

In the mouth, pharynx, and anal canal the epithelium is stratified squamous epithelium. In the stomach and intestines, it is a simple columnar epithelium.

Question 6

What is the submucosa and what does it do?

Answer 6

A broad layer of dense connective tissue connecting the mucosa to the muscularis. It includes blood and lymphatic vessels as well as submucosal glands to release digestive secretions. It also houses the submucosal plexus

Question 7

What is the muscularis and what does it do?

Answer 7

The third layer of the GI tract. In the small intestine it is a double layer of smooth muscle that promote mechanical digestion. At the mouth and anal sphincter, it is skeletal (voluntary) muscle.

Question 8

What is the serosa or adventitia and what does it do?

Answer 8

These hold the GI tract in place

Question 9

What are deciduous teeth and how many do we have?

Answer 9

Baby teeth, 20

Question 10

How many permanent teeth do we have (of each type)

Answer 10

8 incisors
4 canines (or cuspids)
8 premolars (or bicuspids)
12 molars

32 total

Question 11

What is the dentin of a tooth covered by in the root?

Answer 11

Cementum

Question 12

What does the esophagus pass through to access the stomach?

Answer 12

Esophageal hiatus

Question 13

What structure controls the movement of food from the pharynx into the esophagus?

Answer 13

Superior esophageal sphincter

Question 14

At what point does food pass from the esophagus into the stomach?

Answer 14

Inferior esophageal sphincter

Question 15

What is deglutition?

Answer 15

Swallowing

Question 16

What happens in the pharyngeal phase of deglutition?

Answer 16

The uvula and soft palate move upward and close off the nasopharynx

Question 17

What happens during the esophageal phase of deglutition?

Answer 17

Peristalsis propels the food through the esophagus toward the stomach

Question 18

What is the name of the ball of food made in the oral cavity?

Answer 18

Bolus

Question 19

When the stomach deflates inward, it falls into folds called ______

Answer 19

Rugae

Question 20

Each gastric gland secretes through the _____

Answer 20

Gastric pit

Question 21

What cells secrete mucin that protect the stomach from its own acid juice?

Answer 21

Mucous neck cells

Question 22

What do parietal cells do in the stomach?

Answer 22

Produce HCl and intrinsic factor

Question 23

Why does the pH of the stomach need to be so low?

Answer 23

This is needed to activate the protein-digesting enzyme called pepsin

Question 24

What do chief cells do in the stomach?

Answer 24

Secrete pepsinogen, which forms pepsin

Question 25

What do enteroendocrine cells do in the stomach?

Answer 25

Secrete hormones from the stomach into the bloodstream