Brainscape's Knowledge GenomeTM

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


See full index

PHYSL 210 Part 3 > Gastrointestinal Lecture 3 Part 2 Physiology of GI secretions > Flashcards

Gastrointestinal Lecture 3 Part 2 Physiology of GI secretions Flashcards

1
Q

In order to maximize absorption the digestive system has to _______?

A

secrete

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

Approximately how much do we consume?

A
  • Daily fluid intake = ~1.2 L
  • daily solids intake = ~500-800 g
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Daily volume of secretions

A

~7 L

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

What happens to the majority of fluids, solids and secretions?

A

Majority absorbed back into the body, only small volume lost in the feces

  • ~ 100 mL fluid and 50-100 g solids leave through feces
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Origins of gastrointestinal secretions>

A

most come from the accessory glands

  • Salivary glands
  • Liver
  • Gallbladder
  • Pancreas (exocrine)

and small intestine

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

Daily saliva production approx.

A

approx. 1500 mL

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

saliva components

A
  • water (98%)
  • electrolytes
  • mucus
  • enzymes
  • immune modulators
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What saliva components provide lubrication?

A
  • water (98%)
  • electrolytes
  • mucus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Purpose of saliva lubrication

A

protects oral cavity and makes food easier to swallow

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

immune modulators of saliva

A

antibacterial antibodies, WBCs, etc.

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

Which phase of GI regulation does saliva secretion play a role in?

A

Primarily cephalic phase responses

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

Which nervous system does saliva secretion usually occur?

A

autonomic nervous system

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

saliva secretion of PNS and SNS

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

saliva secretion when anxious

A

Anxiety → increased sympathetic drive → decreased salivation/thickening

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

Saliva secretion with appetizing food

A

Appetizing food

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

Daily production of gastric secretions?

A

approx. 2000 mL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Gastric secretions components

A
  • mucus
  • HCl
  • enzymes
  • hormones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

mucus from gastric secretions

A

Lubricates and protects stomach lining

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

HCl from gastric secretions

A
  • Solubilizes some food
  • kills ingested microbes
  • cleaves pepsinogen*
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

enzymes from gastric secretions

A

Pepsinogen → pepsin, cleaves proteins OTHERS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

hormones from gastric secretions

A

Not secreted into stomach, but are secreted from stomach into bloodstream in response to stomach contents

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Origins of gastric secretions

A

cells of the gastric glands → Exocrine glands within the wall of the stomach lining

  • mucus → surface mucous cells
  • HCl → parietal cells
  • enzymes → chief cells (pepsinogen)
  • hormones → ECL cell (Enterochromaffin-like cell) (histamine)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What GI regulation phase egulates HCl production from gastric secretion?

A

Mediated by cephalic and gastric phase responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

what part of gastric secretes HCl?

A

Parietal cells (also known as oxyntic cells) are epithelial cells in the stomach that secrete hydrochloric acid (HCl) and intrinsic factor. These cells are located in the gastric glands found in the lining of the fundus and body regions of the stomach.

25
Q

How do parietal cells release HCl?

A

Signal received and second message may increase secretion by having vesicles with the H+/K+ ATPase pump dock with the membrane and so pumps gets expressed on the cell surface and pumps acid into lumen of the stomach.

26
Q

What detects aa to be present for release of HCl?

A

G-cells (antrum)

Detect the aa in lumen suggesting presence of a protein rick meal, and produce gastric which will enter circulation and signal to ECL cells which in turn will secrete histamine which will signal parietal cells to increase HCl production. Gastric can also work directly on parietal cells

27
Q

What stimulates and inhibits HCl production?

A
  • Stimulated by Gastrin, histamine, and ACh
  • Inhibited by somatostatin
28
Q

WHat happened that was opposite of fletcherism?

A
29
Q

Daily production of pancreatic secretions

A

approx. 1500 mL

30
Q

Pancreatic secretions sometimes referred to as _____?

A

“pancreatic juice”

31
Q

Pancreatic secretion components

A
  • Bicarbonate (HC03-)
  • enzymes
32
Q

Bicarbonate (HC03-) from pancreatic secretions

A

buffer

acts to neutralize the acidity of chyme

33
Q

anatomic considerations for pancreatic secretions

A
  • exocrine cells & duct cells → produce juice and then travel down to duodenum
  • sphincter to help control secretions
  • pancreas and gallbladder secretion are mixed and secreted at the same time
34
Q

GI regulation phase for pancreatic secretions

A

Primarily intestinal phase control, but also cephalic and gastric phase inputs

35
Q

Regulation of HCO3- pancreatic secretion

A
36
Q

Regulation of enzyme pancreatic secretion

A
37
Q

Daily production of bile

A

approx. 500 mL

38
Q

Where is biliary secretion produced?

A

Continuously produced by the liver (dilute bile)

39
Q

Where is biliary secretions stored and concentrated?

A

stored and concentrated in the gallbladder

40
Q

Bile components

A
  • water (~97%)
  • Bile salts (<1%)
  • Bilirubin (<1%)
  • Fats (<1%)
41
Q

Bile salts in biliary secretions

A

solubilize water-insoluble fats

42
Q

Bilirubin in biliary secretions

A

Hemoglobin breakdown product; excreted

43
Q

fats in biliary secretions

A

Includes cholesterol and lecithin (phospholipids); aid digestion

44
Q

What happens when the sphincter of Oddi is closed?

A

The gallbladder also fills up when the sphincter of Oddi is closed, preventing its secretion into the duodenum

45
Q

How is bile concentrated?

A

While in the gallbladder, water and NaCl are absorbed from it – making it more concentrated

46
Q

How does the gallbladder respond to CCK?

A

In response to CCK, the gallbladder contracts and the sphincter of Oddi relaxes, allowing bile to be secreted into the duodenum

47
Q

GI regulation phase of bile secretion

A

Primarily an intestinal phase response

48
Q

Regulation of bile secretion

A
49
Q

Daily intestinal secretions

A

approx. 1500 mL

50
Q

intestinal secretion components

A
  • water/electrolytes
  • mucus
  • enzymes
51
Q

water/ electrolytes in intestinal secretions

A

Maintains fluidity of intestinal contents

52
Q

mucus in intestinal secretions

A

Lubrication and protection of lining of epthelium

53
Q

enzymes in intestinal secretions

A

aid digestion

54
Q

what primarly drives secretion of water into the small intestine?

A

osmosis

55
Q

Where does water secretion into SI occur?

A

Base of intestinal villi surrounded by invaginations of the intestinal wall called the crypts of Lieberkuhn

  • water follows the ions
56
Q

In general, villi are primarily ________, whereas crypts are _________

A

absorptive, secretory

57
Q

What can change water osmolarity?

A

Chyme leaving the stomach and entering the duodenum can change its osmolarity

  • A high concentration of solutes in chyme creates a hypertonic environment
  • Osmotic forces drive water from the plasma into the intestinal lumen
58
Q

Approximately how much of total secretions are absorbed?

A

~6700 mL

PHYSL 210 Part 3 (46 decks)

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