L31.32 Flashcards
What percent of fluid is going to be filtered
20 percent
Carbonic anhydrase inhibitors act on
proximal convoluted tubule
Carbonic anhydrase facilitates (NOT THE INHIBITOR)
Net effect
Na reabsorption
Net effect:
-Urine: increase H+
-Blood: increase HCO3-
Osmotic diuretics effects
proximal tubule
Increase osmolarity of blood and renal filtrate and inhibit resorption of water and sodium
Loop diuretics act on
asending loop of henle
Loop diuretics are used on patients with
hypertension, edema from heart failure or renal insufficiency
Loop diuretic mechanism
Excreted into lumen
Inhibits Na, K, 2Cl symporter which increase excretion of Na, K, Cl
Osmotic gradient decreased leading to increased water excretion
Ca and Mg excreted as well
Percent of sodium filtered
70 percent in proximal
25 percent in thick ascending
5 percent in distal convoluted
Thiazide diuretic location
Secreted by proximal tubules but works in distal convoluted tubule
Thiazide mechanism
inhibit Na-Cl symporter from lumen to tubular cells leading to increase Na-Cl excretion
Thiazide efficacy
low to moderate
K sparing diuretics act on
Cortical collecting tube
K sparing diuretics use
used together in treatment of hypertension and management of congestive heart failure
K sparing diuretics mechanism
Compete with aldosterone or block sodium channels (ENaC)
Normally Na is absorbed and K is pumped out
Mean arterial blood pressure
Cardiac output X Total peripheral resistance
CO=SV x HR
Baroreceptors send BP info to the
Medula
Cells that secrete renin
juxtoglomerular cells
Renin mechanism
Renin converts angiotensinogen(liver) into angiotensin I
Angiotensin converting enzyme(lungs) converts it into Angiotensin II
Sympathoplegic agents
What do they do
Mechanism
lower BP by reducing peripheral vascular resistance and diminishing CO
- Reduce epi release
- block adrenoreceptors
- activate alpha2 receptors
- block beta1 receptors
- -reduce renin and CO
- block alpha1 receptors
- -block vasoconstriction (still need diuretic)
Preferred for patients with mild to moderate hypertension and normal renal and cardiac function
Thiazide diuretics
Direct vasodilators
NO
Reduce Ca influx (L type channels)
Open K channels
Activate dopamine receptors (D1)
Effects of ACE inhibitors
Decrease BP by -Decrease peripheral vascular resistance -Prevent degradation of bradykinin -CO and HR not affected Stabilize Kidney function
Competitive antagonists of angiotensin vs ace inhibitors
more selective because dont affect bradykinin metabolism
