Page 1016 - Fundamentals of anatomy physiology

Chapter 26 The Urinary System 1003

Figure 26–5 The Blood Supply to the Kidneys. ATLAS: Plates 53c,d; 61a–c Glomerulus

Cortical radiate vein Afferent
Cortical radiate artery arterioles

Arcuate artery Cortical
Arcuate vein nephron

Cortical Renal Juxtamedullary
radiate pyramid nephron

veins Cortex Interlobar vein
Cortical Interlobar artery
radiate
arteries Minor calyx
Interlobar b Circulation in a single kidney lobe
arteries
Segmental Renal vein Renal artery
Segmental arteries
artery Arcuate
Adrenal veins
Medulla
artery
Renal
artery
Renal

vein

Interlobar
veins

Interlobar veins Interlobar arteries

Arcuate veins Arcuate arteries

Arcuate Cortical radiate veins Cortical radiate arteries
arteries
a A sectional view, showing major arteries and veins Venules Afferent arterioles

Clinical Note NEPHRONS 26

Peritubular Glomerulus
capillaries

Efferent
arteriole

Analysis of Renal Blood Flow The rate of blood flow c A flowchart of renal circulation
through the kidneys can be estimated by administering the
compound para-aminohippuric acid (PAH). This compound is After passing through the capillaries of the nephrons,
removed by the nephrons and eliminated in urine. Virtually blood enters a network of venules and small veins that con-
all the PAH contained in the blood that arrives at the kid- verge on the cortical radiate veins, also called interlobular
neys is removed before the blood leaves in the renal veins. veins (Figure 26–5a,c). The cortical radiate veins deliver blood
For this reason, renal blood flow can be approximated by to arcuate veins. These veins in turn empty into interlobar
comparing plasma concentrations of PAH with the amount veins, which drain directly into the renal vein. There are no
secreted in urine. In practice, however, it is usually easier to segmental veins.
measure the glomerular filtration rate (p. 1015).