Neural & Hormonal Control of Gastrointestinal Function 1 Flashcards Preview

Gastrointestinal > Neural & Hormonal Control of Gastrointestinal Function 1 > Flashcards

Flashcards in Neural & Hormonal Control of Gastrointestinal Function 1 Deck (35):
1

What are the basic functions of the GI tract?

Digestion of food, absorption of nutrients, excretion of waste, prevention of invasion by pathogens

2

What are the key regulatory requirements of the GI tract?

smooth muscle contraction, secretion of enzymes and solvents, reabsorption of water, coordinate regions

3

What are the interstitial cells of cajal?

Pacemaker cells that produce rhythmic activity in the muscle - act independently of neural activity

4

What provides local control in the GIT?

The enteric nervous system

5

What provides distant control of the GIT?

endocrine system

6

What is the function of the enteric nervous system?

regulate contractile activity and secretion of water and salt

7

What is the function of the endocrine system?

secretion of enzymes and solvents, regulate appetite

8

What are the two layers of the enteric nervous system?

The myenteric plexus and the submucosal plexus

9

What mediators do enteroendocrine cells contain?

Many different mediators depending on their type e.g. CCK, secretin, somatostatin, serotonin, glucagon like peptides 1 and 2 - may contain one or more

10

Where do the hormones of enteroendocrine cells get secreted?

Into the interstitial space and into blood vessels

11

Do the hormones also have a local role?

Yes - paracrine action to excite enteric neurons and extrinsic sensory neurons

12

What do enterochromaffin cell like cells release?

histamine

13

What does the vagus nerve control?

control of swallowing, acid secretion in the stomach, coordinates contraction of stomach an duodenum

14

What controls intestino-intestinal reflexes?

some via vagus, some via DRG and spinal cord

15

What is the role of viscerofugal neurons?

They project from the GIT to pre vertebral sympathetic ganglia to produce reflex inhibition of proximal regions when distal regions are distended

16

What is the cephalic phase of digestion?

The phase triggered by site, smell and taste of food - causes salivation, gastric acid secretion, pepsin secretion and relaxation of gastric corpus and fundus

17

What does the cephalic phase operate via?

Vagus nerve

18

Which cells does the vagus nerve release acetylcholine onto?

parietal cell, ECL cell, D cell and G cell as well as enteric neurons

19

What does the parietal cell secrete?

acid

20

What does the ECL cell secrete?

histamine

21

What does the D cell secrete?

somatostatin

22

What does the G cell secrete?

gastrin

23

How does gastrin and somatostatin reach parietal cells?

Via the portal vein and the liver

24

What excites ECL cells?

acetylcholine

25

What inhibits ECL cells?

somatostatin

26

What else does somatostatin inhibit?

parietal cells and G cells

27

What stimulates D cells?

acid and gastrin

28

What controls peristalsis along the oesophagus?

vagus

29

What is the normal position of the lower oesophageal sphincter?

closed

30

What is GORD?

gastro oesophageal reflux disease

31

What is the response of gastric distension?

Activation of enteric and vagal reflexes, acid and pepsin secretion

32

What causes constriction of the stomach?

interstitial cells of cajal

33

What does food entering the antrum trigger?

Inhibition of acid secretion in the corpus

34

What contributes to the separation of the fat from the food?

acid, protease and mechanical activity

35

Where does the fat go to?

It floats to the fundus and forms a separate layer