Lecture 6 General Principles of GI Flashcards

1
Q

what is the outermost layer of the gut wall

A

Serosa (protection)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is just inside the serosa that shortens the bowel segment upon contraction

A

Longitudinal mucle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what is just inside the longtudinal smooth muscle that decreases the diameter of the lumen?

A

circular muscle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what muscle layer is deep to the circular muscle that causes changes in surface area of the epithelial surface?

A

Muscularis mucosa

mucosa with bundles of mucosal smooth muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what does polarized mean?

A

something is longer than it is wide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what nerve plexus in the gut call causes peristalsis?

A

Myenteric plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the myenteric plexus located?

A

Between the longitudinal layer and the circularis muscles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What nerve plexus in the gut wall controls vasodilation and therefore secretion?

A

Meissner Plexus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

TRUE or FALSE, GI smooth muscle has significantly interconnected with bundles of cells that contract in a single direction with big gap junction for easy ion flow?

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Do many or few connection exist between the major smooth muscle layers?

A

Few

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Smooth muscle DOES NOT have action potential, what happens instead?

A

It is a slow wave rhythm of MEMBRANE POTENTIAL that goes off with stretch or other stimulus (only at the top an AP becomes possible with stimulus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

these action potentials that only occur at the top of waves are actually called?

A

spike potentials
(slow wave created by sodium leakage)
(spike potential created by Ca-Calmodulin)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Intrinsic innervation can happen w/o extrinsic sympathetic and parasympathetic influence, true or false?

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

In the extrinsic pathway, what autonomic system is inhibiting, and excitatory?

A

Parasympathetic is stimulating

Sympathetic is inhibiting

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Through what route does parasympathetic stimulation excite the Gi tract?

A

Parasympathetic stim descends down Vagus CN X, and goes to both Myenteric and Meissner plexuses, which cause contraction and vasodilation/secretion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Besides parasympathetic stimulation increasing the membrane potential, what other two things influence it?

A

Local stretch, and acetylcholine

17
Q

What besides the sympathetic stimulus causes inhibition of the GI tract?

A

Norepinephrine or epinephrine

18
Q

Does the myenteric or submucosal/meissner plexus span the entire length of the GI tract?

A

Just the myenteric

the meissner only controls smaller portions of local mucosa

19
Q

What protein is excreted with a protein meal touches the wall of the duodenum that increases secretions ahead of time?

A

Enterokinase

20
Q

TRUE or FALSE, there are very few sensory fibers in the Myenteric plexus

21
Q

What 5 things can plexus cell bodies detect in the gut and promote excitation or inhibition as a result?

A
Stretch
pH
Irritation
Hormones and signaling molecules
Chemicals (like fats proteins carbs in duodenum)
22
Q

She said just remember this….

A

Sensory cells ARE not epithelial cells

23
Q

what is the visceral-visceral loop

A

a sensory system between the nerve fibers of the gut wall and the greater myenteric & submucosal/meissner plexus. This loop bypasses the need for higher regulation

24
Q

The parasympathetic system innervates all GI structures as far as what?

A

Left colic flexure of colon

25
what nervous division supplies the descending colon, sigmoid, rectum, and facilitates defecation?
Pelvic splanchnic nerves from s2-s4
26
What symathetic plexus innervates liver, gall bladder, stomach, pancreas, large and small intestine to left colic flexure?
Celiac Plexus (with mostly NOREPI)
27
Gastrin is released in the G-cells (parietal) cells that stimulates the production of what?
HCL and promotes mucosal growth (producing Na/H exchangers)
28
Gastrin is located in what 3 places?
Stomach, duodenum, jejunum
29
Gastrin is stimulated by what three local factors?
Presence of proteins, stomach distention, and acetylcholine
30
Gastrin production is inhibited by what factor?
low pH (indirectly responsible for keeping esophogeal sphincter closed normally)
31
Cholecystokinin does what?
Stimulates bicarb and enzyme secretion from the pancreas, contracts the gallbladder, promotes pancreatic growth, inhibits gastric motility
32
Cholecsytokinin is located in what 3 structures?
I-cells of duodenum, jejunum, ileum
33
Cholecsytokinin is stimulated by what 3 things?
proteins, fats, and H+
34
Secretin does what?
promotes pepsin, promotes biliary and pancreatic bicarb secretion, and inhibits HCL secretion (anti gastrin hormone)
35
Secretin is found where?
S-cells of duodenum, jejunum, ileum
36
Secretin is stimulated by what 2 things?
Fat, and acids
37
What are the 2 phases of peristalsis induced by the myenteric plexus?
1. Leading wave of distension | 2. Peristaltic contraction
38
what occurs randomly in the gut, induced by stretch or presence of food bolus?
mixing movments (5-30 seconds in length)