Unit 2: Regulation of GFR, Reabsorption and Secretion (Module 3)

myogenic mechanism and tubuloglomerular feedback

two parts of renal autoregulation of GFR

constrict; decrease

as blood pressure increases, the smooth muscle ___ to ____ GFR

dilates; increase

as blood pressure decreases; the smooth muscle ____ to ____ GFR

myogenic mechanism

helps to maintain a constant GFR, despite changes in the systemic blood pressure; uses smooth muscle in walls of afferent arterioles.

less; H2O

as GFR begins to increase; there is ___ time for reabsorption, causing more Na+ and Cl- to be in the filtrate, therefore having more ___ remain the filtrate

macula densa cells

detect increases in Na+, Cl-, and H2O within the filtrate; located in the ascending LOH

inhibit release of nitric oxide

what do macula densa cells do to regulate GFR?

dilation; vasoconstriction

NO causes ___ of smooth muscle; lack of NO causes ___ of smooth muscle

increase

increase in systemic blood pressure (would) cause a(n) ______ in GFR

vasoconstriction

SNS releases NE which causes ____ of the afferent arteriole

relaxes afferent arteriole, increasing urine output

how is coffee a diuretic?

vasoconstriction

angiotensin II causes ____ of afferent arteriole

increases

atrial naturetic peptide (ANP) _____ GFR

mesangial cells

ANP causes the relaxation of what cells?

increase; increase; increase

relaxation of the mesangial cells due to ANP causes a(n) _____ in glomerular capillary surface area = ____ GFR = ____ urine output (volume)

ANP

only mechanism to increase GFR and not decrease

decreased BP, Na, and blood volume

angiotensin II is secreted in response to…

vasoconstriction and secretion of aldosterone

what does Angiotensin II trigger?

DCT and CD

what parts of the nephron is sodium reabsorbed from when aldosterone is secreted?

dehydration

ADH is secreted in response to…

ADH; DCT & CD

____ increase water permeability in the _____

ADH

stimulates principle cells to insert aquaporin-2 (water channel) into apical membrane to increase permeability

alcohol

this prevents the binding of ADH, causing increased urination

ANP

secreted in response to stretching of the atria, high BP and blood volume

inhibits

ANP ____ Na+ reabsorption

PCT, DCT, CD

what parts of the renal tubule does ANP effect?