Gut L3 Flashcards

1
Q

how much water is taken into the body per day

A

2L

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

HOW MUCH SALIVA IS FORMED IN A DAY

A

1.5L

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

HOW MUCH GASTRIC ACID IS FORMED PER DAY

A

1.5L

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

how much pancreatic juices are formed per day

A

1.5L

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

how much bile is formed per day

A

0.5L

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

how much intestinal secretions is formed per day

A

1.5L

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

how much water is absorbed by the colon per day

A

0.4L

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

how much water is absorbed by the s.int per day

A

8.5L

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

how much water is excreted per day

A

0.1L

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

what happens in the cephalic phase
when is it initiated
what is the purpose
give an example

A
  • initiated when receptors in the head (cephalic) are stimulated by though, sight, smell and taste of food
  • involves PARASYMPATHETIC NS (preganglionic fibres in vagus nerve)
  • prepares body for the influx of food
  • stimulates SALIVA, GASTRIC ACID production
  • causes GALLBLADDER contraction
  • secretion of INSULIN
  • eg Pavlovs dogs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is the importance of the cephalic phase

A

feed forward mechanism

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

saliva contains what?
saliva production is triggered by what
what are the 2 phases of

A
  • mucus, enzymes, lipase and amylase
  • CONDITIONED reflex, triggered by the PARASYMPATHETIC NS
  • BUCCAL/oesophagal phase: food in mouth and swallowing
  • GASTRIC phase: irritating food in stomach causing excess salivation and nausea and vomiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

what are the 3 glands that produce saliva and what % of saliva do they produce

A

SUBMANDIBULAR gland-70%
PARTOID gland- 20%
SUBLINGUAL gland- 5%

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

acid is released from what

A
  • from PARIETAL cells
  • stim by :
  • Ach
  • local HISTAMINE production
  • circulating GASTRIN (hormone) from G cells
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

amount of acid produced is proportional to what

A

the amount of ligands that bind

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

what is the mechanism for HCl secretion

A

H+ and Cl- separately secreted

- H+ secreted by proton pump

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

how can gastric acid secretion be dec

A

1) proton pump inhibitor (O protons can’t enter lumen)

2) histamine receptor drug (removes Histamine as a stimulus for producing HCl, less effective)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

para NS connects with whar

A

submucosal plexus

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

what is phase 2

A

gastric phase

once food is eaten

20
Q

what happens in the gastric phase

A
  • long (3-4 hours)
  • stim by: distension in somach, chemoreceptors detect pH changes
  • secretion of HCl, pepsinogen, intrinsic factor
  • production of MUCUS-BICARBONATE layer (protect stomach from acid)
21
Q

gastritis is what?

what is it a risk factor for

A
  • inflammation of the lining of the stomach

- inc risk of cancer

22
Q

what is the role of the bicarbonate in the stomach

A
  • acts as a buffer, titrate protons that get too close to the mucus layer H+ + HCO3—> H2CO3–> CO2 + H2O
  • H2O produced O makes the mucus more fluid
23
Q

how thick is the mucus layer
what is it composed of
what is release stimulated by

A
  1. 2mm thick
    - 80% CHO, 20% protein
    - release stim by ACh from nerve endings
    - rich in bicarbonate
24
Q

what is the purpose of HCO3- in the mucus layer

what is HCO3- inhibited by

A
  • creates micro env around surface cells to prevent damage

- inhibited ADRRENERGIC INPUT (stress)

25
Q

what is the role of PROSTAGLANDINS in the mucus layer

what happens if you inhibit the nezzymes that make prostaglandins

A
  • cytoprotective
  • inc mucus production
  • inhibition of enzymes causes GASTRIC DAMAGE (eg NSAIDS)
26
Q

what happens if TREFOIL proteins on the mucus layer are absent

A

SIGNIFICANT mucosal damage

27
Q

what is phase 3

A

intestinal phase

28
Q

what happens in phase 3, intestinal phase

A
  • long (hours)
  • cholesystokinin released
  • gastric inhibitory peptide released
  • HCO3- secretions neutralise acidic chyme
  • secretion of DIGESTIVE ENZYMES and bile
  • pH in stomach drops, O somatostatin released, which is the universal inhibitor
29
Q

where are the digestive enzymes in the pancreas

A

Acini clusters which contain Zymogen granules

30
Q

what is found in pancreatic exocrine secretion

A

pancreatic juice, watery solution of enzymes and HCO3-

31
Q

which enzymes are secreted intheir inactive form

whch in active form

A

PROTEASES = inactive to prevent auto-digenstion

AMYLASE and LIPASES = active

32
Q

how is bicarbonate secreted from glands

A
  • Cl- ion moves into pancreatic cell, at the same time HCO3- leaves cell
  • Cl- leaks back into lumen futile cycle) via CFTR (cystic fibrosis transmemb receptor)
33
Q

what causes the problems associated with CF

A
  • malfunctioning CFTR channel O futile cycle is lost
  • can no longer secrete BICARBONATE
  • important for NEUTRALISATION of gastric acid, enzymes being released at th appt pH and not enough FLUIDITY of mucus due to inability to titrate H+ to form H2O
34
Q

what is bile

A

a yellow/green alkaline solution cont bile salts, blue pigments (bilirubin/biliverdin), cholesterol, neutral fats, phospholipids and electrolytes

35
Q

what is the role of bile

A

to emulsify dietary fat

36
Q

what are the 2 components of bile

A

primary bile salts

bile fuild

37
Q

what is in primary bile salts

what is the structure

A
  • cholic acid, chenodeoxycholic acid
  • conjugated w/ GLYCINE or TAURINE and secreted as Na+ salts
  • more soluble in this form
38
Q

what is bile fluid

what does it cont

A

watery secretion cont HCO3- from the epi cells lining the bile canaliculi

39
Q

where ae bile salts released

A

into s.i

40
Q

where is 95% of bile reabs

A

ileum

41
Q

how do bile salts return to liver

A

portal vein, taken up by HEPATOCYTES and resecreted

42
Q

how many times per day is the bile salt pool recycled

A

up to 10 times a day

3-8% lost in faeces

43
Q

how are secondary bile salts formed

A

by bacteria in intetsines by dehydroxylation of primary bile salts

44
Q

deoxycholate (from cholic acid) is absorbed from where

and resecreted from where and in what form

A

absorbed from colon

resecreted by liver as CHOLIC ACID

45
Q

lithocholate (from chenodeoxycholic acid) is absorbed how

A

poorly, it is toxic