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):
1

How many liters of water enters the colon each day?

2L

2

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

T

3

Overgrowth of bacteria can lead to:

the production of toxins that can lead to secretory diarrhea

4

Which epithelium is leaky, proximal or distal colon

proximal epithelium

5

True or False? The distal colon is leaky.

F

6

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

blood positive with respect of the he lumen

7

True or False? Equilibration happens in the distal colon.

F

8

ENac is only found in the:

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

9

Dominance of this exchanger in the distal colon:

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

10

What channel is responsible for neutralizing acid in the colon?

Cl-/ bicarbonate exchanger

11

Total number of flora in the intestines:

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

12

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

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

13

This toxin, produced by bacteria can cause secretion:

?

14

Bacterial population form the ileum on (number):

10^8/ml

15

Butyrate is a metabolite for these cells:

epithelial cells of the colon

16

What can happen if you have a lactase deficiency?

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

Why does fiber help relieve diarrhea?

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

18

Secretory diarrhea is aka:

Active Cl- secretion

19

Incubation period of cholera:

1-5 days

20

Where does the cholera toxin live?

small and large intestines

21

Mortality rate of untreated cholera:

50%, treated is 1-3%

22

Total body water volume:

40L, can lose 10L a day with cholera

23

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

3-6 days

24

Turnover of in the intestinal epithelium (virus):

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

25

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

F. Must differentiate first

26

What can lead to the destruction of crypt cells?

chemotherapy or radiation therapy, lots of fluid loss

27

What cells create the problem in secretory diarrhea?

crypt cells

28

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

T. off or a very low state of on

29

To where does vibrio cholera stick?

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

When will you stop having diarrhea with cholera?

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

Treatment for kids with secretory diarrhea:

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

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

F. lots of K is lost

33

3 types of diarrhea:

osmotic, secretory, and fast motility

34

Laxatives can work via these types of diarrhea:

osmotic or secretory

35

What problem occurs with fast motility?

not enough water reabsorption

36

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

6-8 hours

37

How long does it take to shit out food?

24

38

Main function of segmentation:

mixing

39

Motility in the small intestines is based on:

slow wave contractility

40

How are short peristaltic contractions controlled?

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

41

What nerves control the short peristaltic contractions?

enteric nerves (VIP, NO, ATP)

42

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

short

43

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

T

44

Frequency of slow wave in the large intestines:

3-5/ min

45

most effective propulsion of large masses of food:

mass peristalsis

46

Control of mass movement:

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

47

True or False? Opiates often cause diarrhea.

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

48

How many anal sphincters?

2

49

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

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

50

What nerves control the anal sphincters?

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