lecture 24 - glucose absorption Flashcards Preview

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Flashcards in lecture 24 - glucose absorption Deck (21):
1

SGLT =

sodium-dependent glucose transporter protein

2

tight junctions divide cells into ?

apical and basolateral membrane domains

3

how are the ion gradients necessary for glucose absorption set up?

Na+/K+ pump

4

____ uses energy from Na+ gradient to actively accumulate glucose above its ________ ________

_SGLT_ uses energy from Na+ gradient to actively accumulate glucose above its _Concentration_ _gradient_

5

glucose exits the cell facilitated by _____ transport proteins in the _______ membrane domain, by ________ ________

glucose exits the cell facilitated by _GLUT_ transport proteins in the _basolateral_ membrane domain, by _passive_ _diffusion_

6

what happens to the Na+ which also enters the cell with glucose?

exits via basolateral Na-pump

7

how is osmotic imbalance (due to glucose and Na+ and glucose moving across epithelium) equilibriated ?

paracellular Cl- (down electrical gradient) and water (concentration gradient) fluxes

8

direction of transport through GLUT

either way, depends on concentration gradient

9

oral rehydration therapy

exploits ability for glucose to increase Na+ absorption and hence Cl- and WATER

10

dehydrated babies with diarrhoea given...

simple sugar solution to orally rehydrate them. responsible for saving millions of babies erry year

11

glucose/galactose malabsorption syndrome caused by?

mutation causing gene 1 for glucose symporter, SGLT (in the small intestine), to be knocked-out

12

consequence of glucose/galactose malabsorption syndrome

glucose/galactose accumulate in the lumen of the small intestine, therefore the osmotic imbalance causes water to enter the lumen - ending in watery chyme aka diarrhoea

13

treatment of glucose/galactose malabsorption syndrome

- removal of glucose/galactose from diet - fructose used as carbohydrate source - fructose uses GLUT 5, a facilitative transporter specific to fructose

14

how many litres of body fluid filtered by Kidneys per day?

180 litres per day

15

what will happen if all the glucose filtered out of the blood isn't reabsorbed?

glucose in urine. sweet piss.

16

glucosuria =

glucose accumulating in the urine

17

when does glucosuria occur?

when SGLT protein cannot absorb all the glucose fast enough because the transport maximum of SGLT is exceeded i.e. the renal threshold is surpassed

18

most common cause of glucosuria

diabetes melitus, becuase blood sugar is too high (over 200mg/100mL) due to deficient insulin activity

19

renal threshold =

~200mg/100mL blood plasma. this is the maximum that SGLT can deal with

20

Which protein transports fructose?

GLUT 5

21

which number shows...

- transport maximum

- renal threshold

Q image thumb

1 = renal threshold

2 = transport maximum