Gastric Secretion

Question 1

What does mechanical digestion consist of?

Answer 1

Chewing (mouth)
Churning (stomach)
Segmentation (small intestine)

Question 2

What is propulsion?

Answer 2

Swallowing (oropharynx)

Peristalsis (oesophagus, stomach, small intestine, large intestine)

Question 3

What is the stomachs anatomy?

Answer 3

Mucosa
Submucosa- contains submuscosal plexus
Muscularis externa- contains myentric plexus
Serosa

Question 4

Where does gastric secretion occur?

Answer 4

In the lumen

Question 5

What is stomach mucosa composed of?

Answer 5

Simple columnar epithelium

Gastric pits

Question 6

What do gastric pits lead to?

Answer 6

Gastric glands

Question 7

What do gastric glands produce?

Answer 7

Gastric juice

Question 8

What is Wheater’s Functional Histology of stomach mucosa?

Answer 8

F- foveolae (gastric pits)
CC- chief cells
MM- muscularis mucosae
SM- submucosa

Question 9

What do gastric glands in the fundus and body of the stomach produce?

Answer 9

Most of the gastric juice (oxyntic glands)

Question 10

What does gastric juice aid in?

Answer 10

Stomach functions

Question 11

What do gastric glands comprise?

Answer 11

Hydrochloric acid
Pepsinogen
Intrinsic factor
Mucus

Question 12

What are some examples of gastric gland cells?

Answer 12

Parietal cells
Chief cells
Mucous cells

Question 13

What do Parietal cells do?

Answer 13

Secrete intrinsic factor

Secrete HCl

Question 14

Why is intrinsic factor needed in the body?

Answer 14

Needed for absorption of Vitamin B12

Question 15

Why is HCL needed in the body?

Answer 15

Because it has a pH of roughly 1-3, it has the ability to:
Kill microbes
Denatures proteins
Activate enzymes

Question 16

What do Chief cells do?

Answer 16

Secrete pepsinogen

Secrete gastric lipase

Question 17

Why is pepsinogen needed in the body?

Answer 17

Converted to pepsin by HCL

Breaks certain peptide bonds

Question 18

Why is gastric lipase needed in the body?

Answer 18

Splits short-chain triglycerides into fatty acids and monoglycerides

Question 19

What to mucous cells do?

Answer 19

Secrete mucous
Superficial epithlia
Mucuous neck celss

Question 20

What does mucous do in the body?

Answer 20

Forms a protective barrier

Has alkaline properties

Question 21

What is gastropathy?

Answer 21

Damage to stomach mucosa

Question 22

What can damage stomach mucosa?

Answer 22

Can by caused by drugs, infection, stress, alcohol, radiation therapy

Question 23

What does damage to stomach mucosa cause?

Answer 23

Usually leads to ulceration

Question 24

How is gastric secretion regulated?

Answer 24

Neural and hormonal mechanisms

Question 25

What type of events regulate gastric secretion?

Answer 25

Stimulatory and inhibitory events

Question 26

What are the 3 phases to regulate gastric secretion?

Answer 26

Cephalic (reflex) phase: few minutes prior to food entry Gastric phase: 3–4 hours after food enters the stomach Intestinal phase: brief stimulatory effect as partially digested food enters the duodenum, followed by inhibitory effects

Question 27

What is the cephalic phase?

Answer 27

Smell, sight, thought, taste of food activates CNs Facial, glossopharyngeal and vagus nerves are activated Salivary and gastric glands are activated Prepares mouth and stomach for food

Question 28

What is the gastric phase?

Answer 28

Food distends the stomach and stimulates stretch receptors Chemoreceptors in stomach detect increase in pH peristalsis and gastric juice secretion Chyme empties into duodenum ↓pH and ↓distension

Question 29

What type of feedback loop is the gastric phase?

Answer 29

Negative

Question 30

What is gastric secretion regulated by?

Answer 30

Gastrin

Question 31

What is gastrin released by?

Answer 31

G cells of gastric glands

Question 32

What is gastrin released in response to?

Answer 32

Released in response to food in stomach and parasympathetic stimulation

Question 33

Where is gastrin released into?

Answer 33

Bloodstream

Question 34

What does gastrin stimulate?

Answer 34

Stimulates gastric juice secretion and prevents acid reflux

Question 35

What is gastrin inhibited by?

Answer 35

Inhibited when pH < 2.0 – negative feedback

Question 36

Where does the intestinal phase begin?

Answer 36

Small intestine

Question 37

What does the intestinal phase inhibit?

Answer 37

Exit of chyme from stomach Inhibition of gastric motility Contraction of pyloric sphincter

Question 38

What does the intestinal phase inhibit?

Answer 38

Gastric secretions

Question 39

What does the intestinal phase promote?

Answer 39

Digestion of food in SI | Neural enterogastric reflex

Question 40

What is the hormonal element in the intestinal phase?

Answer 40

CCK and secretin