Lecture 3

Question 1

Closest to Glomerulus?

Answer 1

Proximal Tubule

Question 2

Na+ reabsorption is quantitatively greatest in?

Answer 2

Proximal Tubule (~67%)

Question 3

Reabsorption of most other solutes (and isosmotic reabsorption of water) is?

Answer 3

Quantitatively greatest in PCT

Question 4

Isoosmotic Reabsorption?

Answer 4

No change in Osmolarity

Question 5

TF/plasma?

Answer 5

Concentration in tubule compared to plasma

Question 6

Increase K+?

Answer 6

ICF

Question 7

Increase Na+?

Answer 7

ECF

Question 8

Na+ Dependent Cotransporters?

Answer 8

-Glucose
-HPO4-/SO4-
-Amino Acids

Question 9

Glucose?

Answer 9

(GLUT2)
Passive transport with carrier protein

Question 10

Glucose (SGLT1)?

Answer 10

Driven by Na+ gradient

Question 11

Na+ (SGLT1)?

Answer 11

Active process dependent on Na+

Question 12

(Reabsorption of Glucose)
Filtered?

Answer 12

Increase glucose in plasma = Increase filtration rate

Question 13

(Reabsorption of Glucose)
Excreted Equation?

Answer 13

Excreted = Filtered - Reabsorbed

Question 14

Sodium pumps operate on?

Answer 14

Side facing capillaries

Question 15

Na goes in with?

Answer 15

Cotransporter into cell on Lumen Side

Question 16

Cotransporter uses Na gradient as a?

Answer 16

Driving force (it is active because generated by sodium pump)

Question 17

Cotransporter uses Na gradient as a?

Answer 17

Driving force (it is active because generated by sodium pump)

Question 18

Glucose enters lumen side into cell via?

Answer 18

SGLT1

Question 19

GLUT2?

Answer 19

Like a carrier, glucose goes down chemical gradient

Question 20

Curve 1 (Filtered)?

Answer 20

Amount of glucose being filtered for kidney

Question 21

Curve 3 (Reabsorbed)?

Answer 21

Behaves very similar to group being filtered, then it has a plateau

Question 22

(NaCl Reabsorption in late PCT)
Na+ reabsorption in late PCT occurs?

Answer 22

Mostly with Cl-

Question 23

(NaCl Reabsorption in late PCT)
Both Na+ and Cl- cross?

Answer 23

PCT by transcellular (2/3) and paracellular (1/3) pathways

Question 24

(Osmotic Water Reabsorption in PCT)
Water is passively reabsorbed via?

Answer 24

Transcellular and Paracellular Pathways due to Osmotic gradient established by transport of NaCl

Question 25

Proximal Tubule Summary?

Answer 25

-2/3 of salts and water reabsorbed -All glucose and amino acids reabsorbed -Reabsorption is isotonic (PT Osmolality is isotonic at beginning and end)

Question 26

Na+ Transport Along Nephron?

Answer 26

-Na+ reabsorption is quantitatively greatest in proximal tubule -Reabsorption of most other solutes (and isosmotic reabsorption of water) is also quantitatively greatest in PCT

Question 27

Which portion has NO Na+ reabsorption?

Answer 27

Thin descending limb and Thin ascending limb

Question 28

Thin descending limb of loop of Henle?

Answer 28

-Low permeability to solutes -High permeability to water

Question 29

Thin Descending Limb of Loop of Henle increases in osmolarity because?

Answer 29

H2O leaves

Question 30

Thick Ascending Limb of Loop of Henle (TAL)?

Answer 30

Diluting segment -Impermeable to H2O -Special carriers co-transport ions from tubule to interstitium

Question 31

Counter Current Multiplier creates?

Answer 31

Osmolarity gradient

Question 32

Counter Current Multiplier?

Answer 32

-Increases interstitial osmolarity -Decreases tubular osmolarity

Question 33

Blood moving through kidney removes a lot of?

Answer 33

Osmolites

Question 34

Counter Current Exchange dependent on?

Answer 34

Osmolarity

Question 35

Counter Current Exchange is a function of?

Answer 35

Vasa Recta Capillaries (to provide nutrients and oxygen to deep kidney while maintaining gradient)

Question 36

Distal Convoluted Tubule has?

Answer 36

Decrease Osmolarity

Question 37

Principal Cells in Cortical Collecting Duct?

Answer 37

Absorb Na+ and secrete K+

Question 38

Intercalated Cells in Cortical Collecting Duct?

Answer 38

Secrete acid/base equivalents and can also reabsorb K+

Question 39

Collecting Duct is the site of?

Answer 39

ADH (principal cells) action

Question 40

Collecting Duct is divided into 2 segments?

Answer 40

-Cortical Collecting Duct -Medullary Collecting Duct

Question 41

ADH increases?

Answer 41

Tubular Permeability to Water

Question 42

Binding of ADH to basolateral membrane of principal cells results in?

Answer 42

Insertion of water channels (Aquaporin-2) into apical membrane

Question 43

In absence of ADH, channels are?

Answer 43

Recycled and apical membrane is again impermeable to water

Question 44

In absence of ADH, channels are?

Answer 44

Recycled and apical membrane is again impermeable to water

Question 45

Variable Permeability to H2O is regulated by?

Answer 45

Antidiuretic Hormone (ADH) (concentrate urine)

Question 46

Summary of ADH Actions on Kidneys?

Answer 46

1) Increases permeability of entire collecting duct to water 2) Increases permeability of medullary collecting duct to urea 3) Decreases vasa recta blood flow 4) Increases expression of Na/K/2Cl transporter in thick ascending limb (TAL)