Anatomy and Function of the Kidney

renal cortex

The outer layer of the kidney; contains renal corpuscles and most of the nephron.

renal medulla

The innermost part of the kidney; contains the renal pyramids.

renal pyramids

Cone-shaped tissues in the medulla where urine is collected.

renal columns

Extensions of cortical tissue between renal pyramids.

renal papilla

The tip of the pyramid; urine drains into minor calyx here.

minor calyx

A small funnel-like structure that collects urine from renal papilla.

major calyx

Formed by the fusion of minor calyces; drains into renal pelvis.

renal pelvis

A funnel-shaped reservoir that collects urine and passes it to the ureter.

hilum of the kidney

The medial indentation where vessels, nerves, and ureter enter/exit.

ureters

Tubes that transport urine from kidneys to bladder.

urinary bladder

A muscular sac that stores urine before excretion.

urethra

A tube that carries urine from the bladder to the outside of the body.

prostatic urethra (male)

The portion of urethra passing through the prostate gland.

membranous urethra (male)

The short segment between the prostate and penis.

spongy urethra (male)

The longest part running through the penis.

rugae in the bladder

Folds in the mucosal lining that allow expansion.

trigone

(C) The triangular area in the bladder between ureter and urethra openings.

internal urethral sphincter

Involuntary muscle controlling urine flow from bladder to urethra.

external urethral sphincter

Voluntary muscle controlling urine release from the body.

renal artery

Main artery bringing blood to the kidney.

segmental artery

Branches of the renal artery within the renal sinus.

interlobar artery

Vessels running between renal pyramids in renal columns.

arcuate artery

Artery arching over the base of renal pyramids.

interlobular (cortical radiate) artery

Small arteries radiating through cortex; supply nephrons.

afferent arterioles

Tiny branches that deliver blood to the glomerulus.

glomerulus

A tuft of capillaries where filtration begins.

efferent arterioles

Vessels that carry blood away from the glomerulus.

peritubular capillaries

Capillaries surrounding the tubules in the cortex.

vasa recta

Capillaries around the nephron loop in the medulla.

interlobular (cortical radiate) vein

Small veins draining blood from cortex.

arcuate vein

Vein arching over the base of the pyramids.

interlobar vein

Vein between pyramids collecting blood from arcuate veins.

renal vein

Main vein carrying blood away from the kidney.

renal corpuscle

Includes the glomerulus and glomerular capsule; site of filtration.

glomerular capsule (Bowman's capsule)

Encases the glomerulus and collects filtrate.

podocyte

Specialized cells in the capsule aiding filtration.

proximal convoluted tubule

First tubule after the capsule; site of reabsorption.

nephron loop (Loop of Henle)

U-shaped part; concentrates urine.

descending limb

Permeable to water; reabsorbs water.

ascending limb

Impermeable to water; reabsorbs salts.

distal convoluted tubule

Site of secretion and fine-tuning reabsorption.

collecting duct

Final site of water/salt reabsorption; carries urine to papilla.