Renal Midterm Phys

Front 1

What are the two crucial things that regulate RBF by controllling ease of blood to get to and through the glomerular capillaries?

Back 1

Afferent and efferent arterioles (controlled by innervations)

Front 2

Describe the main type of innervation on the afferent arteriole in RBF

Back 2

Sympathetic innervation is extensive.
- norepinephrine is released vasoconstriction via a1 and a2 receptors

Front 3

Main renal dilator neurotransmitters

Back 3

1. Dopamine- also systemically given for BP control
2. Prostaglandin E2- becomes a major player in certain renal diseases therefore aspirin can be nephrotoxic under certain conditions.

Front 4

With glomerular filtration describe the layers (general)

Back 4

1. Basement membrane

Front 5

What are the two routes for a substance to move into or out of the PCT?

Back 5

1. Paracellular route
2. Transcellular route

Front 6

Describe two important differences between glomerular capillary and systemic capillaries...

Back 6

1. The low resistance of the GC and the presence of the efferent arteriole lead to a very small drop in hydrostatic pressure.
2. 2. The pressures favor filtration throughout the length of the glomerular capillary.

Front 7

Describe the paracellular route for substances to move into or out of the PCT...

Back 7

Between two cells- complicated by the existence of tight junctions between the cells

Front 8

What does aldosterone bind to and do?

Back 8

binds to intracellular receptor moves to nucleus
- Expresses ENaC on apical membrane so Na moves down its concentration gradient into the cell
- Also increases Na/K ATPase on basolateral membrance
- increases K (which stimulate Aldosterone secretion as well)

Front 9

What is GFR?

What is normal GFR?

Back 9

glomerular filtration rate- volume of plasma filtering into Bowman's space every minute
100-125 ml plasma/min (normal range)

Front 10

Describe the transcellular route for substance in the PCT...

Back 10

through the cell- relies on transporter proteins on both the apical and basolateral side of the PCT, although some passive diffusion does occur.

Front 11

Does increase in Na from aldosterone cause increase in blood volume in DCT and CD? Why or Why not?

Back 11

NO! water can not follow because there is not aquaporin-1 in DCT and CD

Front 12

What two numbers do you need to renal plasma flow?

Back 12

1. Renal Blood Flow
2. Hematocrit

Front 13

Where in the hypothalamus does detection of blood osmolarity occur?
What happens when detect increase in extracellular osmolarity?

Back 13

Supraoptic and paraventricular nuclei
- release vasopressin (ADH) from magnocellular neurons stored in Posterior pituitary

Front 14

Knowing RBF = 1.1, and Hct= .45 show how to calculate RPF...

Back 14

RPF = RBF x (1-Hct)
RPF = 1.1 L/min x (1 -.45)
RPF = 1.1 L/min x 0.55
RPF = 0.60 L/min (600 mL/min)

Front 15

What does vasopressin do in DCT and CD?

Back 15

binds to V2R receptor on membranes, which increases adenylate cyclase activity leading to increase in cAMP and activation of PKA
- PKA- phosphorylates aquaporin-2 moving it to the apical membrane

Front 16

Describe the FF (filtration fraction)

Back 16

Is the percent of renal plasma flow that is filtered (moves into Bowman’s space).
FF = GFR/RPF
FF = [120 mL plasma/min]/[600 mL plasma/min]
FF = 0.2
In other words, 20% of the plasma that enters the kidney will also enter Bowman’s space.

Front 17

What transporter transports glucose into the cell and with what?
What transports it out?
Active or Passive?

Back 17

Co transported with Na into cell using SGLT-2
- GLUT-2 transports on the basolateral membrane to the interstitial fluid/blood
- secondary active transport- Na has to move out via active transport

Front 18

What is the tubular load?
Give formula...

Back 18

how much (in mg or g) of a substance enters the tubule each minute (dissolved in the plasma, of course…)
tubular load = GFR x [X]plasma

Front 19

Constriction of the EFFERENT arteriole will ______ blood flow away the glomerular capillaries, _______ the amount of blood in the capillary, _______ the net filtration pressure, _______ GFR

Back 19

decreasej, increase, increase, INCREASING

Front 20

What channel is used to move NaCl in the thick ascending limb?
Where is it located

Back 20

Basolateral border contains NKCC-2 (Na-K-2Cl) moves 4 ions into the cell

Front 21

What happens to small proteins in the PCT?

Back 21

taken up by receptor mediated endocytosis
- once inside the cell, the vesicle fuses with a lysosome and the protein is hydrolyzed into its individual amino acids

Front 22

Describe the role of the vasa recta in the loop of henle in relation to concentrating the urine

Back 22

1. Removing the water before it can dilute the concentrating interstitium.
2. It adds sodium to the interstitium as well.

Front 23

If both the afferent and efferent constrict:
RBF will ______?
GFR may _____?

Back 23

decrease

stay the same

Front 24

What is PAH and its importance?

Back 24

para-aminohippuric acid
- example of an OAT used to access renal function
- 5% protein bound meaning that it will not filter
- eventually thought to be secreted into the lumen using similar OAT

Front 25

What will increase in pieGC (dehydration) lead to in GFR?
What will increase in pieBS usually associated with filtration of proteins like albumin do?

Back 25

1. decrease
2. increase GFR favors filtration

Front 26

Describe the OCTs
What is requirement for OCTs to secrete into the lumen?

Back 26

organic cation transporters

- requires an antiport that moves H+ into cell

Front 27

Describe the mechanisms by name that regulate the GFR...

Back 27

1. Myogenic response
2. Tubuloglomerular feedback

Front 28

List endogenous cations the OCTs work on

Back 28

Endogenous cations
acetylcholine
creatinine
dopamine
epinephrine
norepinephrine
serotonin

Front 29

What is the OATs and what do they do?

Back 29

organic anion transporters on basolateral side in PCT taking things from blood and secreting them to the lumen

Front 30

Name the exogenous cations that the OCTs work on

Back 30

Exogenous cations
atropine
isoproterenol
cimetidine
morphine

Front 31

Describe the bulk operations (reabsorption/secretion) of Urea

Back 31

REabsorbed using transporters UT in PCT
- secreted using OCT in thin ascending limb in loop of henle
- reabsorbed in collecting duct

Front 32

Describe the bulk operations involving Sodium... (reabssorbed/secreted)

Back 32

- 99.4% reabsorbed
- PCT takes 60% or work

Front 33

Describe the Na transporters used in the PCT to reabsorb Na...(5)
Which does the most work?
What type of transporters are these?

Back 33

PCT- all secondary active
SGLT-2,
Na/amino acid,
Na/PO4 co-transporter
Na/lactate co-transporter
Na/H antiport (does most work)

Front 34

Describe the PCT bulk operations of Chloride (Cl-)

Back 34

Two PCT processes
- paracellular pathway
- transcellular pathway (Cl- HCO3 anti-port), Chloride channel (related to CLC1)

Front 35

Describe the PCT bulk operations of Calcium

Back 35

40% bound to proteins so not quite freely filtered
- reabsorbed PCT but not as much as DCT
1. Intracellular Ca++ is very low b/c it is a second messenger
2. Toxic at high concentrations (triggers apoptosis)

Front 36

What special mechanisms does the PCT have to make sure not too much Ca builds up in cell...

Back 36

Ca binds to calbindin to keep intracellular Ca low,
- Ca leaves cell either Ca-ATPase or Na/Ca antiport

Front 37

Describe the PCT bulk operations of Phosphate

Back 37

only 10% wont filter
- major re-absorption (in PCT) is via Na-PO4 co-transporter
- nearly always close to saturation
- increase filtered load increases exretion

Front 38

Describe the steps the PCT does to get HCO3 back...

Back 38

Step1: Cells of PCT use carbonic anhydrase to create H and HCO3
Step 2a: the Na/H antiport is used to kick the newly created H+ into the lumen.
Step 2b: A Na/3 HCO3 symport moves the Na and 3 HCO3 into the blood. The two extra HCO3 are from multiple repetitions of the CA reaction.
Step 3: The filtered HCO3 combines with an H+ in the lumen to recreate the CO2 and H2O
Step 4: The CO2 and H20 will diffuse back into the blood. The water is probably helped along the way

Front 39

Describe bulk operations of H+ secretions

Back 39

PCT cells take glutamine from the liver and run the reaction backwards – combining it with water using glutaminase. The NH4 is moved to the lumen while the glutamate is handled like any amino acid.