About 20-25% of resting cardiac output (1,200 mL of
blood each minute) flows through the kidneys via the renal
arteries and veins. Within each kidney, the renal artery di-
vides into smaller and smaller vessels, shown in the figure,
that eventually deliver blood to the afferent arterioles.
Each afferent arteriole divides into a tangled capillary
network called a glomerulus (glo-MER-u-lus).
The capillaries of the glomerulus reunite to form an
efferent arteriole. Upon leaving the glomeruluis, each ef-
ferent arteriole divides to form a network of capillaries
around the kidney tubules (described next). These capil-
laries eventually reunite to form veins, which merge into
larger and larger veins. Eventually, all these smaller veins
drain into the renal vein.
Blood supply of nephron
Path of Blood Flow
A rc u a te arteries
C o rtica l ra diate arteries
A ffe re n t a rte rio le s
E ffe re n t arteriole s
A rcu a te v e in s
In te rlo b a r ve in s
b. Frontal section of right kidney showing path of blood
The Urinary System Plays a Vital Role in Maintaining Homeostasis