Renal physiology: Proximal Convoluted Tubule

Question 1

lining of PCT

Answer 1

simple cuboidal epithelium

Question 2

specialisations of the PCT

Answer 2

brush border on apical side to increase surface area
lots of mitochondria for transport
ion channels on apical and basolateral membrane

Question 3

2 parts of the PCT

Answer 3

pars convolute
pars recta

Question 4

pars convolute

Answer 4

in the renal cortex and divided into S1 and proximal S2

Question 5

pars recta

Answer 5

straight segment in outer medulla, distal S2 and S3

Question 6

reabsorption

Answer 6

water and solutes to the blood stream
from the PCT to interstitium to peritubular capillaries
isoosmotic

Question 7

% of Na, water, K and Cl reabsorbed

Answer 7

65%

Question 8

% of glucose and amino acids reabsorbed

Answer 8

100%

Question 9

% of bicarbonate reabsorbed

Answer 9

85-90%

Question 10

basolateral

Answer 10

faces the intersittium

Question 11

apical

Answer 11

faces the tubular lumen

Question 12

2 routes for reabsorption

Answer 12

paracellular
transcellular

Question 13

transcellular

Answer 13

solutes through a cell

Question 14

paracellular

Answer 14

solutes between cells through the intercellular space

Question 15

what is S1 not permeable to

Answer 15

urea and Cl
concentration increases
will form a conc grad used in S2 and 3

Question 16

types of co-transport

Answer 16

symporter
antiporter

Question 17

symporter

Answer 17

transports 2+ molecules in the same direction
SGLT

Question 18

antiporter

Answer 18

transports 2+ molecules in oppositve directions
Na+/K+ ATPase

Question 19

what does the sodium conc grad allow

Answer 19

other molecules to be transproted across the apical membrane against their con grad

Question 20

SGLT

Answer 20

1 glucose and 2 sodium across the apical membrane
glucose crosses basolateral membrane via facilitated diffusion

Question 21

Na+/amino acid symporter

Answer 21

spical side
S1
reabsorbs all amino acids in the PCT

Question 22

Na+/H+ antiporter

Answer 22

apical surface of PCT
Na+ to tubular cells
H+ to lumen
maintians pH

Question 23

movement of water

Answer 23

large solute volumes in the bloodstream
solute concentration decreases
solute in the intersititum increases
water moves by osmosis to the intersittium
paracellular route mainly

Question 24

how much blood is filtered in glomerulus

Answer 24

20%

Question 25

what does the PCT secrete

Answer 25

organic acids and bases: bile salts, oxalate and catecholamines
H+
drugs/ toxins

Question 26

h+ secretion

Answer 26

maintains acid base balance
allows bicarb reabsroption
using carbonic anhydrase
every H+ secreted 1 Na and bicarbonate reabsorbed into the blood
no net H+ excretion

Question 27

drugs/ toxins secretion

Answer 27

of organic cations: dopamine/ mrphine
occur via H+/OC+ exchanger on the apical side of the tube
driven by the Na+/H+ antiporter