4.1 Digestive System Part 1 Flashcards Preview

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Flashcards in 4.1 Digestive System Part 1 Deck (30):
1

4 tissue layers of digestive tract

Mucosa
Submucosa
Muscularis
Serosa
Myenteric plexus

2

Mucosa Function

Absorption and secretion

3

Submucosa function

Secretion

4

Muscularis function

Motility

5

Myenteric plexus function

Innervation
-Motility
-Stretch detection
"Gut brain"

6

What does the myenteric plexus regulate?

Muscularis motility and secretions

7

How much CNS input does the myenteric plexus operate under?

Minimal due to pacemaker capacity

8

Enteric Nervous System (ENS)

Myenteric plexus and submucosal plexus

9

Is the myenteric plexus responsive to the sympathetic or parasympathetic branch?

BOTH

10

What is the submucosal plexus?

"Middle man," regulates secretions by exocrine glands within submucosal layers

11

Is the submucosal plexus responsive to the sympathetic or parasympathetic branch?

Parasympathetic ONLY

12

Plexus

Bunch of neurons working together

13

Basal Electrical Rhythm (BER)

Some GI neurons have a pacemaker rhythm ~3-12 depolarizations / minute

14

How is BER spread?

Spread throughout the longitudinal smooth muscles in muscularis (via gap junctions)

15

BER stimulates motility in muscularis for...

Peristalsis and mixing

16

Peristalsis

Propulsive, unidirectional movement

17

Mixing

Back and forth

18

What is the BER pacemaker similar to?

SA node in heart

19

How does the BER pacemaker work?

Na+ leakage leads to firing of action potential.. Ca influx and muscle contraction

20

What in the BER determines the number of action potentials and then the force of contractions?

Resting membrane potential (hyper polarized -> fewer action potentials, etc)

21

What in the BER determines the number of action potentials and then the force of contractions?

Resting membrane potential (hyper polarized -> fewer action potentials, etc)

22

What does the parasympathetic division do to the RMP in BER pacemaker cells?

Depolarizes it

23

Easier activation of BER pacemaker cells leads to...

-Increased glandular secretions
-Increased peristaltic contraction

24

What does the sympathetic division do to the RMP in BER pacemaker cells?

Hyper polarizes it

25

Slow contractions in GI motility leads to this phenomenon...

"Butterflies"

26

How does the myenteric plexus modify motility locally?

Via vasoactive intestinal peptide

27

Vasoactive intestinal peptide (VIP)

Neurotransmitter that relaxes regions out in front of a bolus material

28

What does VIP respond to?

Physical stretching by foodstuff

29

Chemo and mechanoreceptors send afferent signals back to the CNS via the....

Vagus nerve

30

Mechanoreceptors: Highly fibrous, bulky foodstuff would lead to...

Stretch receptor activation and a feeling of satiety