Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SFIV Test 1 > Stomach II > Flashcards

Stomach II Flashcards

1
Q

How does ACh stimulate acid secretion?

A

Activates phospholipase C, catalyzes formation of IP3, causes Ca release

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

How does histamine stimulate acid secretion?

A

Binds to H2 receptors

Activates adenylyl cyclase to form cAMP

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

How does gastrin stimulate acid secretion?

A

Binds to gastrin/CCK-B receptors

Activates PLC –> formation of IP3 –> release of Ca

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

How do Ca and cAMP increase acid secretion?

A

Incrase concentrations of (H,K) ATPases and Cl channels int eh apical membrane

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

What is potentiation?

A

Occurs when response to simultaneous administration of two stimulants greater than sum of response to either agent given alone

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

What are the potentiation affects of histamine and ACh?

A

Histamine potentiates actions of gastrin and ACh

ACh potentiates actions of histamine and gastrin

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

Why are H2 receptor blockers effective in inhibiting acid secretion?

A

Block not only action of histamine but histamine’s potentiating effects on ACh and gastrin

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

What are the actions of enterochromaffin-like cell?

A

Has receptors for gastrin and ACh

Both stimulate release and synthesis of histamine and proliferation of cells, but ACh moreso that gastrin

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

How does low pH inhibit acid secretion?

A

Below 3, gastrin release inhibited via a negative feedback loop

Somatostatin released, inhibiting acid secretion by parietal cells and gastrin secretion by G cells

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

How does chyme in the duodenum inhibit acid secretion?

A

Both neural and humoral mechanisms

Triggered by acidity, osmolarity, and fat content of chyme

Inhibit gastrin/ and acid secretion by parietal cell

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

What are the four phases of acid secretion?

A

Basal secretion

Cephalic phase

Gastric phase

Intestinal phase

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

What is the basal secretion phase?

A

Occurs in the absence of all gastric stimulation

Show circadian rhythm, occurs between meals

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

What is the cephalic phase of secretion?

A

Initiated by thought sight, taste, or smell

Vagal stimulation causes ACh stimulation of parietal cells

ACh also causes release of GRP

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

What is the gastric phase of secretion?

A

Initiated by entry of food into the stomach

Distenstion initiates local and vagovagal reflexes, which stimulate both gastrin release via GRP and acid secretion via ACh

Protein causes gastric secretion during this phase

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

What is the intestinal phase of acid secretion?

A

Initiated by presence of protein digestion products in the duodenum

Proximal duodenum secretes gastrin, stimulating acid production

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

What are gastric ulcers?

A

Caused when protective barrier of stomach breaks down

Usually found in distal stomach

H secretion into stomach reduced because some acid leaks into gastric mucosa and is lost

17
Q

What are duodenal ulcers?

A

Defect in defense mechanisms against acid, High levels of acid and pepsin damage duodenal cells, pepsin potentiates ulcer formation, lower levels of bicarb secretion

18
Q

What is Helicobactor pylori?

A

Almost all ulcer patients infected

Breaks down gastric epithelial barrier

NH4 produced by bacteria damage gastric mucosal cells

In duodenum, appears to inhibit secretion of SS, allowing increased gastrin release and acid production

19
Q

What substances can cause stomach damage?

A

Alcohol

NSAIDs (aspirin)

20
Q

What are treatments for ulcers?

A

Antibiotics - H. pylori

PPIs

Usually combination of two antibiotics and PPI

21
Q

What is the mechanism of emesis (vomiting)?

A

Waves on contractions begin in distal small intestine, moving GI contents towards stomach

retching involves all involuntary motions of vomiting without production

General ANS discharge before and during emesis leads to increased salivation, sweating, tachypnea, and irregular heartbeat

22
Q

What is the vomiting center?

A

Located in medulla, activated by afferent impulses

Direct actiation causes vomiting w/o nausea or retching

Stimulation of second, separate medullary area leads to retching w/o vomiting

The two areas usually interact with each other

23
Q

What is the chemoreceptor trigger zone (CTZ)?

A

In area postrema

Activated by emetics, drugs, and radiation sickness

24
Q

What is the role of serotonin in vomiting?

A

Released from ECL cells in small intestine

Initiates impulses that trigger vomiting

Antagonist can prevent vomiting

25
Q

What is morning sickness?

A

Believed to have evolved to protect fetus early in development when toxins can cause most damage

Affects 70-85% of pregnant women

26
Q

What are the affects of protracted vomiting?

A

Metabolic alkalosis

Hypokalemia due to loss of K and decreased K uptake

Hyponatremia due to loss of Na

Dehydration

SFIV Test 1 (16 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions