GI1

Question 1

how is the GI system regulated?

Answer 1

• innervation
• hormonal control
• immune control
• trophic effects

Question 2

what is feeding?

Answer 2

the acquisition and ingestion of food

Question 3

what species has the simplest GI system?

Answer 3

C. elegans

Question 4

ezymatic digestion is the breakdown of what?

Answer 4

starches/sugars, proteins and fats

Question 5

fermentative digestion involves what/

Answer 5

symbiotic microbes

Question 6

bacteria in your gut can break down antioxidants in chocolate into what

Answer 6

anti-inflammatory compounds

Question 7

what kind of digestion do carnivores have?

Answer 7

primarily enzymatic

Question 8

what kind of digestion do omnivores have?

Answer 8

enzymatic and fermentative

Question 9

______ ______ and ____ control are essential for GI functions

Answer 9

• intrinsic neural

- endocrine

Question 10

what does motility do?

Answer 10

moves food

Question 11

what does digestion do?

Answer 11

secretion of digestive substances

Question 12

what does absorption do?

Answer 12

transports nutrients from the lumen to the blood

Question 13

what is delivery?

Answer 13

circulation/distribution of absorbed substances

Question 14

how is the GI protection?

Answer 14

• barrier function

- defense mechanism against pathogen invasion

Question 15

what are the two parts of the extrinsic system?

Answer 15

• nerves (PS;S)

- extrinsic hormanal

Question 16

what are the 4 parts to intrinsic systems?

Answer 16

• intrinsic hormonal
• immune control
• trophic effects
• nerves (ENS)

Question 17

what does the “autonomy of the GI system” mean?

Answer 17

that the GI system is self-regulating

Question 18

what intrinsically regulates the GI system ?

Answer 18

enteric nervous system

-neurogenic control of both secretion and GI motility

Question 19

what are the three components to the ANS?

Answer 19

PS, S, ENS

Question 20

how is the ENS modulated?

Answer 20

inputs from the extrinsic PS and S components

Question 21

what is the submucosal plexus, what is the name of one, and where is it located?

Answer 21

-secretions and local blood flow
-Meissner’s plexus
located in the submucosal layer

Question 22

what is the myenteric plexus, what is the name of one, and where is it located?

Answer 22

• muscle contraction and motility
• Auerbach;s plexus
• located between the circular and longitudinal muscles layers

Question 23

what are two properties of the ENS neurons?

Answer 23

they have collaterals and varicosities

Question 24

what is the input for chemoreceptors?

Answer 24

luminal chemical conditions

Question 25

what is the input for mechanoreceptors

Answer 25

distension within muscle layers

Question 26

what are the output targets for excitatory neurons (e.g ACh, Sustance P)

Answer 26

glands: secretion (or not)

Question 27

what are the output targets for inhibitory neurons (e.g. NO, VIP)

Answer 27

Muscle layers: contraction/relaxation

Question 28

what extrinsic components of the parasympathetic NS act on the GI?

Answer 28

- vagus n - pelvic n - pre-ganglionic - stimulatory*** - ACh (cholinergic

Question 29

what extrinsic components of the sympathetic NS act on the GI?

Answer 29

- splanchnic n - primarily post-ganglionic - inhibitory - norepi (adrenergic)

Question 30

what NT does the ENS use?

Answer 30

NO and VIP

Question 31

parasympathetic neurons (stimulate/inhibit) motility?

Answer 31

stimulate

Question 32

sympathetic neurons (stimulate/inhibit) motility?

Answer 32

inhibit

Question 33

can the sympathetic NS override the PS influence on the GI tract?

Answer 33

YES

Question 34

where do the PS fibers synapse?

Answer 34

on the ENS cell bodies