Absorption by the Large Intestine/ Intestinal Secretion and Motility Flashcards Preview

Physiology > Absorption by the Large Intestine/ Intestinal Secretion and Motility > Flashcards

Flashcards in Absorption by the Large Intestine/ Intestinal Secretion and Motility Deck (50)
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1
Q

How many liters of water enters the colon each day?

A

2L

2
Q

True or False? Nutrients are produced by the bacteria in the colon.

A

T

3
Q

Overgrowth of bacteria can lead to:

A

the production of toxins that can lead to secretory diarrhea

4
Q

Which epithelium is leaky, proximal or distal colon

A

proximal epithelium

5
Q

True or False? The distal colon is leaky.

A

F

6
Q

is the blood side of the colon positive of negative in relation to the lumen?

A

blood positive with respect of the he lumen

7
Q

True or False? Equilibration happens in the distal colon.

A

F

8
Q

ENac is only found in the:

A

distal tubule (tighte epithelium) and the distal colon, regulated by aldosterone. take up extra sodium, leads to low sodium in feces

9
Q

Dominance of this exchanger in the distal colon:

A

Cl- bicarbonate exchanger, neutralize the acid created by the bacteria

10
Q

What channel is responsible for neutralizing acid in the colon?

A

Cl-/ bicarbonate exchanger

11
Q

Total number of flora in the intestines:

A

limited in duodenum and jejunum, rise in ileum and the large intestines

12
Q

True or False? Most bacteria in the colon are aerobic.

A

F. Anaerobic. outnumber aerobes by 1,000-10,000:1

13
Q

This toxin, produced by bacteria can cause secretion:

A

?

14
Q

Bacterial population form the ileum on (number):

A

10^8/ml

15
Q

Butyrate is a metabolite for these cells:

A

epithelial cells of the colon

16
Q

What can happen if you have a lactase deficiency?

A

Organic ions that are osmotically active, can raise the osmolarity of the lumen. Low water concentration relative to interstitial fluid (400mOsm) leads to diarrhea

17
Q

Why does fiber help relieve diarrhea?

A

bacteria act on cellulose that we can’t digest, raises the osmolarity of the lumen, which leads to diarrhea

18
Q

Secretory diarrhea is aka:

A

Active Cl- secretion

19
Q

Incubation period of cholera:

A

1-5 days

20
Q

Where does the cholera toxin live?

A

small and large intestines

21
Q

Mortality rate of untreated cholera:

A

50%, treated is 1-3%

22
Q

Total body water volume:

A

40L, can lose 10L a day with cholera

23
Q

How long does it take for cholera to run its course?

A

3-6 days

24
Q

Turnover of in the intestinal epithelium (virus):

A

3-5 days, stem cells in crypt area divide and differentiate toe express transporters

25
Q

True or False? Stem cell in the crypt have transporters.

A

F. Must differentiate first

26
Q

What can lead to the destruction of crypt cells?

A

chemotherapy or radiation therapy, lots of fluid loss

27
Q

What cells create the problem in secretory diarrhea?

A

crypt cells

28
Q

True or False? The CFTR channels are almost always off in the basal state.

A

T. off or a very low state of on

29
Q

To where does vibrio cholera stick?

A

brush border of epithelial cells, GM1 ganglioside receptor, sugar proteins in apical membrane, toxin breaks into p[arts, moves from basolateral to apical membrane, activate G coupled receptor that is already there and permanently turns on G protein complex, producing continuous supply of cAMP, which activate PKA, that activates the CFTR channel and Cl- leaks out

30
Q

When will you stop having diarrhea with cholera?

A

the bacteria is washed out in the first day or two and you have to wait until all the initial infected cells are turned over (3-5 days) must keep the patient hydrated to survive those days

31
Q

Treatment for kids with secretory diarrhea:

A

rice water, oral glucose is better treatment, glucose so provides substrate for sodium/ glucose cotransporter, can stimulate enough water absorption to offset the diarrhea

32
Q

True or False? Very little K is lost in diarrhea.

A

F. lots of K is lost

33
Q

3 types of diarrhea:

A

osmotic, secretory, and fast motility

34
Q

Laxatives can work via these types of diarrhea:

A

osmotic or secretory

35
Q

What problem occurs with fast motility?

A

not enough water reabsorption

36
Q

how long does it take for food to get to the end of the ileum?

A

6-8 hours

37
Q

How long does it take to shit out food?

A

24

38
Q

Main function of segmentation:

A

mixing

39
Q

Motility in the small intestines is based on:

A

slow wave contractility

40
Q

How are short peristaltic contractions controlled?

A

controlled only by stretching of the wall of the small or large intestines, double reflex: contraction/ relaxation

41
Q

What nerves control the short peristaltic contractions?

A

enteric nerves (VIP, NO, ATP)

42
Q

Are short peristaltic contractions involved in short or long distance (movement) of bolus?

A

short

43
Q

True or False? There is slow wave activity in the large intestines.

A

T

44
Q

Frequency of slow wave in the large intestines:

A

3-5/ min

45
Q

most effective propulsion of large masses of food:

A

mass peristalsis

46
Q

Control of mass movement:

A

enteric nerves due to local distension, enteric nerves, anything related to eating

47
Q

True or False? Opiates often cause diarrhea.

A

F. slow motility, cause constipation. Lomtil will do the same

48
Q

How many anal sphincters?

A

2

49
Q

True or False? The internal anal sphincter is what prevent the release of feces.

A

F. Relaxes more and more with pressure, external prevent defecation

50
Q

What nerves control the anal sphincters?

A

enteric nerves, signal to external anal sphincter to contract and also telling the internal to relax, and a signal the urge to defecate