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Renal ` RENAL—PhysioLogy Renal ` RENAL—PhysioLogy SeCTIOn III 589
Juxtaglomerular Consists of mesangial cells, JG cells (modified JGA maintains GFR via renin-angiotensin-
apparatus smooth muscle of afferent arteriole), and the aldosterone system.
macula densa (NaCl sensor, located at distal In addition to vasodilatory properties, β-blockers
end of loop of Henle). JG cells secrete renin can decrease BP by inhibiting β -receptors of
1
in response to renal blood pressure and the JGA renin release.
sympathetic tone (β ). Macula densa cells
1
sense NaCl delivery to DCT renin
release efferent arteriole vasoconstriction
GFR.
Kidney endocrine functions
Erythropoietin Released by interstitial cells in peritubular Stimulates RBC proliferation in bone marrow.
capillary bed in response to hypoxia. Administered for anemia secondary to chronic
kidney disease. risk of HTN.
Calciferol (vitamin D) PCT cells convert 25-OH vitamin D to 1,25-
3 25-OH D 3 1,25-(OH) D 3
2
(OH) vitamin D (calcitriol, active form). (calcidiol) 1α-hydroxylase (calcitriol)
2 3
PTH
Prostaglandins Paracrine secretion vasodilates the afferent NSAIDs block renal-protective prostaglandin
arterioles to RBF. synthesis constriction of afferent arteriole
and GFR; this may result in acute kidney
injury in low renal blood flow states.
Dopamine Secreted by PCT cells, promotes natriuresis. At
low doses; dilates interlobular arteries, afferent
arterioles, efferent arterioles RBF, little
or no change in GFR. At higher doses; acts as
vasoconstrictor.
FAS1_2019_14-Renal.indd 589 11/7/19 5:42 PM
