physiology proximal tubule and loop of henle

Question 1

what is glomerular filtrate?

Answer 1

-is a modified filtrate of the blood (i.e. contains ions and solutes at plasma concentrations but lacks RBCs, large plasma proteins)

Question 2

what is reabsorbed in the proximal tubule?

Answer 2

• sugars
• amino acids
• phosphate
• sulphate
• lactate

Question 3

what is secreted in the proximal tubule?

Answer 3

• H+
• hippurates
• neurotransmitters
• bile pigments
• uric acid
• drugs
• toxins

Question 4

what are primary active transporters?

Answer 4

-proteins that require energy to operate the carrier and move the substrate against its concentration gradient

Question 5

what are secondary active transporter?

Answer 5

one where the carrier molecule is transported couples to the concentration gradient of an ion (usually Na+)

Question 6

what is facilitated diffusion?

Answer 6

passive carrier mediated transport of a substance down its concentration gradient

Question 7

what is isosmotic fluid reabsorption across the ‘leaky’ proximal tubule epithelium due to?

Answer 7

• standing osmotic gradient

- oncotic pressure gradient

Question 8

transport of glucose slide

Answer 8

Question 9

summary PT

Question 10

what is the function of the loop of henle?

Answer 10

Question 11

what is being reabsorbed in the ascending limb of the loop of Henle?

Answer 11

Na+ and Cl- are being reabsorbed

Question 12

is the ascending limb of the loop of Henle permeable to water?

Answer 12

no, it is relatively impermeable to water reabsorption so little or no water follows the salt reabsorption

Question 13

does the descending limb of the loop of Henle reabsorb water?

Answer 13

yes, it is highly permeable to water

Question 14

does the descending limb of the loop of Henle reabsorb NaCl?

Answer 14

no

Question 15

which part of the loop of henle reabsorbs Na and Cl but is impermeable to water?

Answer 15

ascending limb

Question 16

Question 17

Question 18

Question 19