Lecture 34 Unit 5

Question 1

what is the relationship between tubular fluid and blood at the end of the PCT

Answer 1

isotonic

Question 2

what is the relationship between tubular fluid and blood at the end of the loop of henle

Answer 2

hypotonic to blood

Question 3

what is the relationship between tubular fluid and blood at the renal corpuscle

Answer 3

isotonic to blood

Question 4

what does most reabsorption

Answer 4

PCT

Question 5

what does the rest of the nephron besides the PCT do

Answer 5

• solutes reabsorbed by active and passive processes
• water follows solutes by osmosis
• small proteins move across into the blood by pinocytosis

Question 6

what does tubular secretion do

Answer 6

transfers materials fr9m blood into tubular fluid

Question 7

what happens in tubular secretion

Answer 7

• controls blood pH through secretion of H+

- helps eliminate certain substances

Question 8

what happens in paracellular reabsorption

Answer 8

-50% of reabsorbed material moves between cells by diffusion in some parts of tubule

Question 9

what happens in transcellular reabsorption

Answer 9

material moves through both the apical and basal membranes of the tubule cell by active transport

Question 10

how is Na+ reabsorbed

Answer 10

Na+/K+ ATPase pumps sodium from tubule cell cytosol through the basolateral membrane

Question 11

what is obligatory water reabsorption

Answer 11

when water is obliged to follow the solutes being reabsorbed

Question 12

what is facultative water reabsorption

Answer 12

occurs in collecting duct under the control of ADH

Question 13

what helps reabsorb materials from filtrate in PCT

Answer 13

Na+ symporters

Question 14

how are intracellular sodium levels kept low

Answer 14

Na+/K+ pumps on the basolateral side

Question 15

what is glycosuria

Answer 15

some glucose remains in the urine

Question 16

what happens if blood glucose levels exceed 200 mg/ml

Answer 16

renal symporters cannot reabsorb glucose fast enough

Question 17

what happens in diabetes mellitus

Answer 17

insulin activity is deficient and blood glucose cannot enter cells as readily

Question 18

what is the renal threshold for glucose

Answer 18

200 mg/mL

Question 19

how does the loop of henle reabsorb ions

Answer 19

Na+/K+/2Cl- symporters

Question 20

how does K+ move into filtrate in the loop of henle

Answer 20

K+ leak channels

Question 21

how is Na+ reabsorbed in loop of henle

Answer 21

Na+ is pumped out on basolateral side

Question 22

how is Cl- reasbroed in loop of henle

Answer 22

diffusion

Question 23

how do cations move to vasa recta

Answer 23

passively

Question 24

what is thick ascending limb impermeable to

Answer 24

water

Question 25

is early DCT permeable to water

Answer 25

yes

Question 26

are Na+ and Cl- reabsorbed by different symporters than loop of henle

Answer 26

yes

Question 27

all water reabsorption until late DCT is what?

Answer 27

obligatory

Question 28

what are the cells in the late DCT

Answer 28

principal cells and intercalated cells

Question 29

what do principal cells do

Answer 29

reabsorb na+ and secrete k+

Question 30

what do intercalated cells do

Answer 30

reabsorb K+ and HCO3- and secrete H+

Question 31

what would happen without ADH

Answer 31

late DCT and CD are impermeable to water

Question 32

throughout journey through nephron what happens to tubular fluid

Answer 32

volume is decreasing

Question 33

what is goal of producing dilute urine

Answer 33

remove excess fluid from blood

Question 34

what is the concentration if blood plasma

Answer 34

300 mOsm/L

Question 35

what happens to filtrate osmolarity as it moves down loop of henle

Answer 35

increases

Question 36

what happens to filtrate osmolarity as it moves up loop of henle

Answer 36

decreases

Question 37

what happens to filtrate osmolarity is CD

Answer 37

decreases so it produced dilute urine

Question 38

what is the goal of concentrated urine

Answer 38

prevent water loss by excreting only concentrated urine

Question 39

what happens as the concentration of ADH increases

Answer 39

more aquaporin channels are inserted into apical membranes of principal cells

Question 40

water reabsorption in late DCT and CD is what?

Answer 40

optional -facultative reabsorption

Question 41

what are the ADH actions leading to concentrated urine

Answer 41

- stimualtes Na+/K+/Cl- symporters in thick limb of ascending loop of henle - stimulates facultative water reabsorption in upper and lower CD - stimulates urea recycling in lower CD