Brainscape's Knowledge GenomeTM

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


See full index

Physiology Part 1 > Lec 20 GI Secretory Function > Flashcards

Lec 20 GI Secretory Function Flashcards

1
Q

What 3 things in salivary secretion?

A
  • bicarbonate
  • salivary amylase
  • lingual lipase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

is saliva isotonic, hypotonic, or hypertonic?

A

hypotonic

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

What happens to salivary bicarbonate concentration as salivary flow increases?

A

bicarbonate concentration increases

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

What are the two organs and functions of the stomach?

A

fundus and body: secretion reservoir

antrum: mixing and grinding

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

What 3 things are first secreted in stomach when food enters?

A
  • Vagus/parasympathetic secretes acetylcholine
  • ECL cells secrete histamine
  • G cells secrete gastrin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What 4 things are responsible for turning on parietal and chief cell secretions?

A
  • vagal activity [ACh]
  • gastric distension
  • gastrin
  • histamine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What 2 things do parietal cells secrete?

A

Acid [H+]

Intrinsic Factor [IF]

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

What cells secrete gastrin?

A

G cells in antrum

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

What do chief cells secrete?

A

pepsinogen

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

What are two sources of lipase

A

lingual –> saliva

gastric: cells in fundus

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

What cells in glands in proximal stomach vs distal?

A

proximal: ECL cells, chief cells, parietal cells
distal: G and D cells
both: mucous cells

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

How many layers of muscle in stomach? What are they?

A
  • circular
  • oblique
  • longitudinal
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What type of action is histamine [hormone, paracrine, autocrine, etc]?

A

paracrine –> released from ECL cells and activates parietal cells at local level

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

What are foveolar cells?

A

mucus secreting cells

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

what type of cells in mucous neck?

A

gastric stem cells

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

In parietal cell – what happens to H+, Cl-, HCO3-, K+?

A
  • K enters cell via Na/K ATPase on basolateral side
  • K exits via K channel on lumen and reenters via H/K ATPase that pumps H+ out into lumen
  • Positive charge in lumen attracts Cl- that exits cell via Cl channel passively
  • HCO3- produced as by-product of acid exits basolateral side into blood stream
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is mech by which parietal cell activated?

A
  • ACh to M3, Histamine to H2, or Gastrin to CCK-B
  • at activation, increase cellular Ca [in case of ACh or gastrin] or AMP [via histamine] which causes H/K ATPase to migrate to luminal cell surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What 2 things activate ECL cell to release histamine?

A
  • Acetylcholine

- Gastrin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How does gastrin act on parietal cell [direct and indirect]?

A
  • activates parietal cell to secrete HCl

- activates ECL to secrete histamine that then induces further HCl secretion by parietal

20
Q

How does vagus/ACh act on parietal cell [direct and indirect]?

A
  • activates parietal cell to secrete HCl

- activates ECL to secrete histamine that induces further HCl secretion by parietal

21
Q

How does somatostatin act on parietal cell [direct and indirect]?

A
  • inhibits parietal cell HCl secretion
  • inhibits G cell gastrin secretion [main function, paracrine]
  • inhibits ECL cell histamine secretion
22
Q

What activates somatostatin release from D cell?

A
  • HCl produced in proximal stomach travels down to distal stomach where D cell senses the low pH and releases SST
23
Q

What does D cell secrete?

A

somatostatin

24
Q

What is GRP?

A
  • a peptide released by parasympathetic nerves in response to distention
  • causes G cell to release gastrin
25
Q

what happens to gastrin if no acid in stomach

A

its elevated

26
Q

what does gastrin do? what does it act on?

A
  • hormone released from G cell
  • activates ECL cell to release histamine
  • activates chief cell to release pepsinogen
  • activates parietal cell to release H
27
Q

What does distention of stomach do?

A
  • can turn on acid production
28
Q

what is the functional unit of the pancreas

A

gland lined by acinar cells

29
Q

What do pancreatic duct cells secrete?

A
  • release HCO3 into lumen via Cl/HCO3 exchanger

- release Cl via CFTR channel

30
Q

How does CAMP affect pancreatic duct cell secretion?

A
  • CAMP causes increased Cl secretion via CFTR into lumen
31
Q

What 3 things in pancreatic duct cell are stimulated by hormone secretin?

A
  • more Cl secreted out to lumen via CFTR
  • increased activity Cl/HCO3 exchanger [Cl into cell from lumen, HCO3 out to lumen]
  • increased activity NBC [exchanges HCO3 into cell from basolateral side, Na out basolateral to blood stream]
32
Q

How does pancreatic flow affect pancreatic bicarbonate conc?

A
  • increased pancreatic flow –> increased pancreatic bicarbonate concentration
33
Q

What causes s cells to produce secretin?

A

acid coming into lumen

34
Q

What do pancreatic acinar cells secrete? What 5 things activate their secretion [via what 2 secondary messengers]

A
  • enzymes released from granules into duodenum
    release activated by:
  • GRP, ACh [m3], CCK [CCK] via Ca
  • VIP, Secretin via cAMP

PRIMARY TRIGGER = CCK

35
Q

What are bile acids formed from?

A

cholesterol

36
Q

How are primary bile acids formed from cholesterol? where are they secreted? where reabsorbed?

A

formed: via dehydroxylase and conjugation with glycine/taurine to make them soluble
secreted: into bile
reabsorbed: in terminal ileum

37
Q

How are secondary bile acids formed from cholesterol? where are they secreted? where reabsorbed?

A

formed: via dehydroxylase primary bile acids [by bacteria] by bacteria
reabsorbed: by colon, conjugated by liver, secreted back into bile

38
Q

What are major effects of bile acid conjugation?

A
  • lowers pKa to enhance hydrophilicity [makes more water soluble]
  • reduces passive diffusion across cell membranes in transit in biliary tree
39
Q

Where are conjugated bile acids reabsorbed?

A
  • in terminal ileum

- circulate back to liver via enterohepatic circulation

40
Q

What are micelles? function?

A
  • bile acids form sphere with hydrophobic part in center, hydrophilic part on outside
  • hydrophobic interior allows to package that fats while still staying soluble
  • transport lipids for absorption
41
Q

What are components of human bile?

A
  • 2/3 primary and secondary bile salts

- some phospholipids, cholesterol, protein, bilirubin, electrolytes

42
Q

Where does fat absorption occur?

A

jejunum and ileum

43
Q

What is possible consequence of getting rid of ileum?

A
  • mess up enterohepatic circualtion
  • don’t get enough reabsorption of bile salts
  • liver can’t make enough to compensate so get bile salt deficiency
44
Q

What 4 things tell bile duct to make HCO3?

A
  • secretin
  • CCK
  • gastrin
  • vagal stimulation [ACh]
45
Q

What do VIP/NO do to sphincter of oddi?

A
  • relax sphincter so allow stuff to come through when gall bladder contracted above
46
Q

What 2 things tell gall bladder to secrete bile salts?

A
  • CCK

- ACh [vagal]

47
Q

What is responsible for vagal afferent signal to tell vagus to induce bile salt secretion?

A

CCK

Physiology Part 1 (37 decks)

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