Final Exam GI Physiology Questions Flashcards Preview

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Flashcards in Final Exam GI Physiology Questions Deck (66)
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1

What hypothalamic neurotransmitters help control hunger and satiety centers?

CCK, CRH, Neuropeptide Y, and Leptin

2

What control mechanisms help to achieve INTRINSIC control of the GI Tract?

Enteric Nervous System
Endocrine Cells in the gut wall
Cells that secrete paracrine substances
Local tissue factors

3

Where would you find interneurons of the enteric nervous system and what are they commonly known as? What do they do?

Submucosa (Meissner's) plexi
Myenteric (Auerbach's) plexi
They synapse onto muscles, glands, and secretory and absorptive epithelium.

4

What do endocrine cells in the gut wall respond to?

Directly to GI tract luminal contents
NTs
Paracrine substances

5

Histamine, somatostatin, prostaglandins, and serotonin are examples of what kind of substance?

Paracrine substances

6

What are the MOST important sites of hormone production in the GI Tract?

Stomach and Small Intestine

7

What is a local tissue factor?

Simple products of metabolism whose concentrations affect neighboring blood vessels.

8

Increased concentration of tissue factors (CO2, H+, and K+) result in ____________ of neighboring blood vessels.

Vasodilation

9

What control mechanisms help to achieve EXTRINSIC control of the GI Tract?

Afferent neurons projecting from GI Tract to either extramural plexi or CNS

Afferent neurons that convey sensory info to the CNS

SNS and PSNS EFFerent neurons

Somatic nervous system EFFerent neurons

Endocrine cells outside the gut wall

10

What control mechanisms help to achieve DIRECT control of the GI Tract?

The direct interaction of NTs, hormones and paracrine substances with gut wall muscles, glandular tissue, and secretory or absorptive epithelium

11

How is INDIRECT control of the GI Tract achieved?

Through regulation of perfusion

12

The GI system can receive up to what percent of cardiac output when active?

30%

13

What is the overall effect of SNS stimulation?

Vasoconstriction and decreased blood flow

14

What do SNS postganglionic neurons secrete?

NE

15

What receptors predominate at GI vasculature?

alpha-1 adrenergic receptors

16

What do PSNS postganglionic neurons secrete?

VIP and ACh

17

What does VIP do?

Inhibits actin-myosin interaction in muscle

Promotes production of NO which leads to vasodilation

18

What does ACh do?

Promotes production of NO which leads to vasodilation

19

What does Epinephrine from the adrenal medulla do when stimulating alpha-1 adrenergic receptors?

Vasoconstriction

20

What does Epinephrine do when stimulating beta-2 adrenergic receptors?

Vasodilation

21

The effects of epinephrine stimulation prevail on which receptors?

alpha-1

22

What does gastrin and other peptide hormones of the GIT do?

Vasodilation

23

Which two substances have a powerful vasoconstrictive effect resulting from a decreased ECV (effective circulating volume)?

Angiotensin II and ADH

24

Histamine and Prostaglandins (paracrine secretions) are _______ in effect.

Histamine and prostaglandins are vasodilatory

25

Local tissue factors like CO2, H+ and K+ are __________.

CO2, H+, and K+ are vasodilatory

26

At rest, the kidneys require what percent of cardiac output?

22%

27

At rest, the GI tract and Liver together require what percent of cardiac output?

23%

28

Where in the GI Tract would you find VSM (visceral smooth muscle)?

From the esophagus to the internal anal sphincter.

29

The VSM (visceral smooth muscles) exhibit a spontaneous pattern of depolarization and repolarization called ____ ____.

Slow waves

30

Where are slow waves generated?

In the myenteric plexus by interstitial cells.