Absorption by the Large Intestine/ Intestinal Secretion and Motility

Question 1

How many liters of water enters the colon each day?

Answer 1

2L

Question 2

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

Answer 2

T

Question 3

Overgrowth of bacteria can lead to:

Answer 3

the production of toxins that can lead to secretory diarrhea

Question 4

Which epithelium is leaky, proximal or distal colon

Answer 4

proximal epithelium

Question 5

True or False? The distal colon is leaky.

Answer 5

F

Question 6

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

Answer 6

blood positive with respect of the he lumen

Question 7

True or False? Equilibration happens in the distal colon.

Answer 7

F

Question 8

ENac is only found in the:

Answer 8

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

Question 9

Dominance of this exchanger in the distal colon:

Answer 9

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

Question 10

What channel is responsible for neutralizing acid in the colon?

Answer 10

Cl-/ bicarbonate exchanger

Question 11

Total number of flora in the intestines:

Answer 11

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

Question 12

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

Answer 12

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

Question 13

This toxin, produced by bacteria can cause secretion:

Answer 13

?

Question 14

Bacterial population form the ileum on (number):

Answer 14

10^8/ml

Question 15

Butyrate is a metabolite for these cells:

Answer 15

epithelial cells of the colon

Question 16

What can happen if you have a lactase deficiency?

Answer 16

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

Question 17

Why does fiber help relieve diarrhea?

Answer 17

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

Question 18

Secretory diarrhea is aka:

Answer 18

Active Cl- secretion

Question 19

Incubation period of cholera:

Answer 19

1-5 days

Question 20

Where does the cholera toxin live?

Answer 20

small and large intestines

Question 21

Mortality rate of untreated cholera:

Answer 21

50%, treated is 1-3%

Question 22

Total body water volume:

Answer 22

40L, can lose 10L a day with cholera

Question 23

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

Answer 23

3-6 days

Question 24

Turnover of in the intestinal epithelium (virus):

Answer 24

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

Question 25

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

Answer 25

F. Must differentiate first

Question 26

What can lead to the destruction of crypt cells?

Answer 26

chemotherapy or radiation therapy, lots of fluid loss

Question 27

What cells create the problem in secretory diarrhea?

Answer 27

crypt cells

Question 28

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

Answer 28

T. off or a very low state of on

Question 29

To where does vibrio cholera stick?

Answer 29

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

Question 30

When will you stop having diarrhea with cholera?

Answer 30

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

Question 31

Treatment for kids with secretory diarrhea:

Answer 31

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

Question 32

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

Answer 32

F. lots of K is lost

Question 33

3 types of diarrhea:

Answer 33

osmotic, secretory, and fast motility

Question 34

Laxatives can work via these types of diarrhea:

Answer 34

osmotic or secretory

Question 35

What problem occurs with fast motility?

Answer 35

not enough water reabsorption

Question 36

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

Answer 36

6-8 hours

Question 37

How long does it take to shit out food?

Answer 37

24

Question 38

Main function of segmentation:

Answer 38

mixing

Question 39

Motility in the small intestines is based on:

Answer 39

slow wave contractility

Question 40

How are short peristaltic contractions controlled?

Answer 40

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

Question 41

What nerves control the short peristaltic contractions?

Answer 41

enteric nerves (VIP, NO, ATP)

Question 42

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

Answer 42

short

Question 43

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

Answer 43

T

Question 44

Frequency of slow wave in the large intestines:

Answer 44

3-5/ min

Question 45

most effective propulsion of large masses of food:

Answer 45

mass peristalsis

Question 46

Control of mass movement:

Answer 46

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

Question 47

True or False? Opiates often cause diarrhea.

Answer 47

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

Question 48

How many anal sphincters?

Answer 48

2

Question 49

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

Answer 49

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

Question 50

What nerves control the anal sphincters?

Answer 50

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