Renal Key terms

Question 1

Glomerular Filtration Rate

Answer 1

Amount of plasma filtered from the glomeruli into the Bowman’s space per unit time

Question 2

Filtration Fraction

Answer 2

GFR/RPF

Question 3

Renal Plasma Flow (RPF)

Answer 3

RBF x (1-hematocrit)

Question 4

Filtration

Answer 4

GFR x [P]substance

Question 5

Factors that Affect GFP

Answer 5

Favoring filtration: Ph
Opposing filtration: Pfluid/PBS and n

Question 6

What does Ph, PBS, n stand for?

Answer 6

Ph= glomerular hydrostatic pressure
PBS= Bowman’s hydrostatic pressure
n= colloid osmotic pressure (due to proteins in plasma but not in Bowmans)

Question 7

Net Glomerular filtration pressure

Answer 7

Ph-PBS-n

Question 8

GFR equation

Answer 8

GFR=Kf x (Ph-PBS-n)

Question 9

3 Variables that influence Ph

Answer 9

arterial pressure
afferent arterial resistance (increasing resistance decreases Ph)
efferent arterial resistance (increasing resistance increases Ph)

Question 10

Autoregulation of GFR

Answer 10

Myogenic response
Tubuloglomerular feedback
Hormones and autonomic neurons

Question 11

Renal clearance

Answer 11

a measure of renal excretion ability: volume of plasma from which “x” is completely cleared per unit time

Question 12

renal clearance (Cx) equations

Answer 12

([U]x * V)/([P]x) or E/[P]x

Question 13

What does [U]x, V, [P]x mean

Answer 13

[U]x = urine concentration of x
V = urine flow rate
[P]x = plasma concentration of x

Question 14

GFR = Cx when x is…

Answer 14

freely filtered by glomerulus
not reabsorbed by tubules
not secreted by tubules
not broken down by tubules
not synthesized by tubules
criteria met by inulin

Question 15

Cx = RBF when x is…

Answer 15

freely filtered
completely secreted through tubular secretions
criteria met by PAH

Question 16

Renal reabsorption: PCT

Answer 16

water, organic materials, glucose, NA, K, Cl, nutrients, Amino acids, and vitamins

Question 17

Renal reabsorption: LH

Answer 17

descending: water
ascending: Na, K, Cl, Ca, HCO3

Question 18

Renal reabsorption: DCT

Answer 18

selective reabsorption: Na, Cl, water
active secretion: ions and acids

Question 19

Renal reabsorption: CD

Answer 19

Na, Cl, urea, (water if ADH is present)

Question 20

Reabsorption principles

Answer 20

1. Na is reabsorbed by active transport (active transport drives osmolarity)
2. electrochemical gradient drives anion reabsorption
3. water moves by osmosis following solute reabsorption (creates increase of solute conc. in lumen)
4. permeable solutes are reabsorbed by diffusion

Question 21

Renal Threshold

Answer 21

plasma concentration at which a solute begins to show up in urine

Question 22

Tubular Maximum

Answer 22

highest transport rate

Question 23

Filtration drives slope

Answer 23

high GFR= steep slope
low GFR= shallow slope

Question 24

increasing cotransporters does what

Answer 24

increases reabsorption and moves threshold right`

Question 25

PT reabsorption- Na reabsorption

Answer 25

active transport basolateral side symport, antiport, leak channels on apical side

Question 26

Na co-transports with ___ and counter-transports with _____

Answer 26

co transports: glucose, Amino acids, organic solutes
Counter transports: H+

Question 27

PT reabsorption- urea

Answer 27

passive transport due to urea concentration gradient
transcellular and paracellular pathways

Question 28

PT reabsorption- transcytosis

Answer 28

some small peptides can pass through by receptor mediated endocytosis

Question 29

PT secretion

Answer 29

H+ through Na/H exchanger
ammonia ions through Na/NH4 antiport
transported molecules cross epithelium by secondary and tertiary transport and have broad specificity

Question 30

LH Reabsorption

Answer 30

thin descending- permeaby to water, moderate to ions
thin ascending- impermeable to water, permeable to ions
thick ascending- impermeable to water and ions BUT actively pumps out Na and Cl

Question 31

What nephrons create osmolarity gradient

Answer 31

Juxtamedullary

Question 32

DT and CD reabsorption

Answer 32

Na/Cl- aldosterone sensitive
water- ADH sensitive

Question 33

DT and CD secretion

Answer 33

K+- aldosterone sensitive
H+ ADH sensitive
NH4+, organic ions, creatinine, penecilin

K+ exchanged for Na
H+ exchanged for K

Question 34

Acidosis

Answer 34

Type A intercalated cells
high H+ in interstitial space
pumps H+ into the renal tubule and increases K/Na in the blood

Question 35

Alkydosis

Answer 35

Type B intercalated cells
low H+ in interstitial space
pumps H+ from tubule into interstitial space
increases K+ in urine

Question 36

ADH (vasopressin)

Answer 36

causes the insertion of water pores into apical membrane
increases water reabsorption into blood

Question 37

Aldosterone

Answer 37

helps reabsorb Na and secrete K
released when BP is high and extracellular K is high

Question 38

Aldosterone has a direct effect on potassium

Answer 38

increase plasma K- increases aldosterone- increases tubular secretion of K
prevents hyperkalamia

Question 39

Urine

Answer 39

medullary osmotic gradient- established by juxtamedullary nephrones
CD exploit this gradient to create concentrated urine

Question 40

Countercurrent multiplier

Answer 40

Nephron
ascending generates the gradient and descending multiplies it

Question 41

Countercurrent exchanger

Answer 41

vasa recta
maintains osmotic gradient while delivering blood (net gain=0)
blood flows down: salt in, water out
blood flows up: salt out, water in