Anatomy of the kidney

The urinary tract is composed of two kidneys, two ureters, the urinary bladder and one urethra.

Anatomy of the urinary tract

Blood is filtered in the renal cortex and medulla, resulting in concentrated ,primary urine . Then urine flows across the cup shaped major calyces. Peristaltic contractions drive urine flow through the renal pelvis and the ureters (25-35 cm long) into the bladder. The female urethra is shorter than the male urethra, which explains the more frequent occurrence of urinary tract infections in women.

Longitudinal section of the kidney	The nephron

The nephron is the kidney’s functional unit. Each kidney contains approximately one million nephrons. The loss of a significant amount of nephrons (i.e. chronic renal diseases) seriously impairs renal function. A nephron is composed of:

• a glomerulus with a tuft of capillaries and the Bowman's capsule
• a proximal tubule (convoluted and straight tubule)
• a loop of Henle
• a distal tubule (convoluted and straight tubule)
• a collecting duct

The packed nephrons constitute the renal parenchyma.