RAAS. Dialysis

Question 1

What are the triggers for Renin release?

Answer 1

Low blood pressure, sympathetic nervous cell, low Na in the distal convulted tubule

Question 2

Where is renin released

Answer 2

Relased from the JuxtaGlomerular cells (smooth muscle cells)

Question 3

How is the macula densa involved in renin release?

Answer 3

In distal tubule of nephron, senses low Na (low bp leads to less Na). Stimulated via local PGs

Question 4

Where is angiotensinogen made

Answer 4

Liver cells. Not active.

Combines with renin

Question 5

Where is ACE found?

Answer 5

Blood vessels and lungs

Question 6

List the sites of angiotensin II active

Answer 6

Smooth muscle of blood vessels- constriction
Kidney- water rention, increase GFR by vasconstriction of efferent
Pituitary Gland ADH release
Adrenal Gland- Aldosterone release

Question 7

How are volume and osmolarity affected with aldosterone versus ADH

Answer 7

Aldosterone: Increase in volume with no change in osmolarity as porportional change
ADH: Inverserly related if volume increased Osmolarity decreases

Question 8

Where is aldosterone made and why

Answer 8

Made from cholesterol in the adrenal cortex. Stimulated by Angiotensin II and increased K+

Question 9

Where does aldosterone have it’s action

Answer 9

Principal cells in the late distal convulted tubule and collecting duct

Question 10

What are the affects of aldosterone locally and in the blood

Answer 10

Makes Na/K atpase pump work harder; K+ channels in apical membrane (efflux); Na channels in apical membrane (influx)
Blood: Loose K+; Na + increases; Water increase

Question 11

Where does ADH have its affect and how

Answer 11

Collecting duct cells that are impermeable to water. Aquaporins are placed in the cells to allow water to move through.

Question 12

How does Aldosterone alter pH

Answer 12

Alpha interculated cells. When too acidic will give HCO3- (exchange with Cl-) to blood to form H20/CO2
Cl-goes to blood through channel
H+ leaves through transporter through apical membrane; channel exchange for Na+

Question 13

What is renal replacement therapy

Answer 13

Blood circulated in an extracorpeal circuit its composition is modified by a mass transfer of solute and water by diffusive/convective forces accros an interfacing semipermebale membrane

Question 14

Define diffusion in dialysis

Answer 14

Movement down concentration gradient or thermodynamic potenetial

Question 15

What are the determinates for diffusion

Answer 15

Molecular weight (inverse)
molecular charge, protien binding, volume of distribution; celluar seclusion

Question 16

Define Convection in dialysis

Answer 16

water driven through membrane by hydrostatic pressure gradients, solutes disolved in water move through by solvent drag

Question 17

What are the determinates for convection

Answer 17

hydrostatic pressure gradient, hydralic pressure and membrane surface area / seiving coefficent

Question 18

Define adsorption

Answer 18

molecular attachement of a solute to a material surface. Hemoperfusion

Question 19

What is the primary mechanism for Intermitent hemodialysis, CRRT, CVVHDF

Answer 19

IHD: Diffusion (some convection, adsorption)
CRRT: Convection (some diffusion adsoprtion)
CVVHDF: Both diffusion convection

Question 20

What is dialysis disequilibrium syndrome and how to avoid

Answer 20

Removal of solutes results in gradient, plasma water moves from vascular to intracellular space. When solutes are removed with small volume relative to the efficiency
Avoid reduce urea <5% /hr for > 300 mg/dl and <10% for <300 mg/dl BUN

Question 21

What are characteristics to use RRT for toxicity

Answer 21

Low molecular weight (< 1500 Da)
Small volume of distribution
Minimal protien binding
Add hemoperfusion if don’t meet.

Question 22

What is peritoneal dialysis

Answer 22

Removal of metabolites and water by the administration of a large amount of dialysate solution into the peritoneal cavity.

Question 23

What is the primary mechanisms for peritoneal dialysis

Answer 23

Membrane is the peritoneal membrane.
Diffusion, convection, osmosis (ultrafiltration)
Osmosis- water movement

Question 24

List complications of RRT

Answer 24

Hemorrhage- heparization

HypoCa - citrate anticoagulation

Question 25

What is the difference in aphresis and TPE

Answer 25

Aphresis: Blood removed and seperated into its componenets then one or more is processed/removed and returned to patient
TPE is aphresis of the plasma

Question 26

What determines the success of TPE

Answer 26

Volume of distribution
rapiditiy substance equilibrates between body compartments
ability to remove adequate amounts

Question 27

Disease process in which TPE may be used to treat

Answer 27

Myasthenia Gravis, IMHA, Multiple myeloma, IMpolyradiculoneuritis

Question 28

Complications of TPE

Answer 28

plasma rxns, hypocalcemia/alkalsosis- citrate; blood loss- clot in circuti; hypotension, hypoprotienemia