Block 3 Physi- Na-K electron LEc4

Decrease in GFR decreases

Na+ excretion

There are changes in filtration pressure with _____ blood pressure

decreased

Aldosterone increases ___ reabsorption

Na+

Aldosterone increases Na+ reabsorption in the

late distal tubule and collecting duct Angi

otensin II is not a steroid but rather a

peptide

Angiotensinogen is converted to angiotensin I by

Renin

Angiotensin I is converted into angiotensin II by

ACE

Renin is secreted into the

kidney

Angiotensin II increases

Na+ reabsorption

Angiotensin II increased Na+ reabsorption by… (4 situations)

increased aldosterone, proximal reabsorption, and filtration fraction (FF) along wiht decreasing Kf (surface area)

Angiotensin II constricts both ____ and ____ but has more effect on _____

afferent and efferent arterioles; efferent

Angiotensin II is the most potent way to

constrict arterioles

Angiotensin II increases Na+ reabsorption leading to the result of

protein osmotic pressure increased in peritubular capillaries (to increase absorption)

Angiotensin II generally leaves ____ unchanged

GFR

atrial natriuretic peptide (ANP) is released when

there is atrial stretch (due to volume expansion)

When ANP is released, it leads to

vasodilation (decreased BP) and increased Na+ and H2O excretion

Actions of ANP is mediated by

cGMP

Differences between ANP, BNP and CNP

ANP (Atria/other tissues), BNP (Brain, atria, ventricles), CNP (CNS, vasculature)

BNP levels are a very useful indicator of if you have

heart failure

ANP (ANF) _____ Na+ reabsorption

decreases

increase in ANP leads to increase also in

GFR (leading to increased sodium excretion)

Increased ANP leads to decreased

aldosterone

Decreased protein osmotic pressure ___ Na+ excretion

increases (glomerulus)

Decreased protein osmotic pressure increases Na+ excretion in the glomerulus AND the…

proximal tube

Sympathetic ___ Na+ reabsorption

increases

Sympathetic nerves sites of action to affect Na+ reabsorption

aterterioles, JG cells, Kf, and Tubules

Symapthetics (norepi or epi) increase the active Na/K ATPase and thus…

increase Na absorption

Angiotensin II has similar effects as ____ but has a different receptor

sympathetic nerve stimulation

Increased blood flow to the cortex results in

increased Na+ excretion

Pressure natriuresis/diuresis is an increase of

Na_/water excretion

Pressure antriuresis/diuresis is caused by an increase in

arterial pressure in the absence of a change in renal blood flow and glomerular filtration rate

Na+ reasborption is quantitaively greatest in the

proximal tubule

reabsorption of most other solutes is greatest in the

proximal convoluted tubule

Liddle syndrome is a disorder characterized by

hypertension with low plasma renin activity, metabolic alkalosis and hypoaldosteronism

Regulation of Na+ Excretion overal factors !

hemodynamics, aldosterone, ANP, sympathetics (KEY), angiotensin II, and protein osmotic pressure

ADH ____ tubular permeability to water

increases

Binding of ADH to the ____ of principal cells results in ____

basolateral membrane; insertion of water channels (aquaporin)

The cortical collecting duct and medullary collecting duct have variable permeability to H2O that is regualted by

ADH

Primary control of H2O excretion is by

ADH

The reabsorption of solutes is _____ on the reabsorption of water

not dependant

The reabsorption of water is ____ on the reabsorption of solutes

dependant

Increased solute excretion nearly always results in

increased urine flow

Secretion of ADH is stimulated by

physio factors, other hormones and drugs A

Angiotesin II stimulates ___ release

ADH

ANP inhibits ____ release

ADH

100% of the filtered K+ is reabsorbed by the

beginning of the distal tubule

Aldosterone regualtes _____ excretion

potassium

Aldosterone is regulated by what two factors

Amount of aldosterone in the body and the plasma potassium

Aldosterone increases K+ secretion and K+ stimulates

K+ secretion directly

Mg2+ is absorbed in the ____ and excretion affected by ___

TAL; diuretics

Prathyroid hormone (PTH) decreases reabsorption of ____ in proximal tubule

phosphate

Parathydroid increases reabsorption off ___ in DT and CD

calcium

Vitamine D increases reabsorption of

Calcium in DT

Active form of vitamin D is made in the

kidneys

(T/F) Na+ excretion will be decreased when Sympathetic tone is increases

True

(T/F) Aldosterone increases Na+ reabsorption and K+ secretion

True

(T/F) ANP is released by atrial stretch and increases Na+ reabsorption

False

(T/F) Diuretics cause hypokalemia by over-stimulating K+ secretion

True