bulk reabsorption in the PCT

Question 1

sequence of events in the Nephron

Answer 1

filtration - pressure forces filtration of waste-laden blood in the glomerulus
reabsorption
secretion

Question 2

what is reabsorption

Answer 2

process of returning important substances from filtrate back to body

Question 3

what is secretion

Answer 3

movement of waste materials from the body to the filtrate

Question 4

what is tubular reabsorption

Answer 4

process of returning important substances from filtrate back into renal interstitium then into renal blood vessels and then back to body

Question 5

what do tubular cells have to increase surface area for reabsorption

Answer 5

microvilli/brush border on apical membrane

Question 6

other components of tubular cells

Answer 6

large amount of NAK-ATPase on basolateral membrane
large amount of carbonic anhydrase enzyme

Question 7

description of the oncotic pressure in the peritubular capillaries of the kidney

Answer 7

increased oncotic pressure compared with normal capillary blood

Question 8

transportation of sodium in tubular reabsorption

Answer 8

actively transported over basolateral membrane (blood capillary side) of tubular cell out of tubular cells towards peritubular capillaries.
sets up sodium gradient which drives Na movement across apical (filtrate side) membrane

Question 9

what follows sodium down its electrochemical gradient

Answer 9

negatively charged chloride

Question 10

what follows sodium and chlorine when they set up an osmotic gradient

Answer 10

water by osmosis

Question 11

what does the bulk movement of water cause

Answer 11

solvent drag
diffusion

Question 12

what is glucose transport dependent on

Answer 12

specific membrane proteins

Question 13

why is there not a limit on how much glucose can be filtered into the PCT?

Answer 13

glucose is freely filtered and does not saturate.

Question 14

what does glucose filtration depend on

Answer 14

plasma concentration

Question 15

why is glucose reabsorption from the PCT limited

Answer 15

rate of flow of the filtrate - decreased rate increases reabsorption
number of protein transporters

Question 16

what substance does not exhibit a transport maximum but requires protein carriers

Answer 16

sodium

Question 17

difference of phosphate reabsorption to glucose reabsorption

Answer 17

hormonally regulated

Question 18

what hormone regulates phosphate reabsorption

Answer 18

parathyroid hormone

Question 19

effect of PTH on phosphate reabsorption

Answer 19

reduces therefore increasing phosphate excretion

Question 20

where does reabsorption occur

Answer 20

proximal convoluted tube (PCT)

Question 21

what provides the energy for the transport from the lumen of the PCT back to the plasma

Answer 21

sodium/potassium pump

Question 22

what does the sodium/potassium pump fuel

Answer 22

secondary active transport
diffusion
osmosis

Question 23

functional adaptations of the PCT that enables large volume reabsorption of H20 and solutes

Answer 23

large surface area
single layer of epithelial cells
high concentration of Na, K ATPase
high concentration of carbonic anhydrase
asymmetrical distribution of Na, K ATPase
peritubular capillaries continuous with efferent arteriole have very high oncotic pressure

Question 24

why is most of filtrate being immediately reabsorbed back into the blood in the PCT advantageous

Answer 24

able to swiftly remove toxic substances from the blood that are freely filtered at the renal corpuscle