9C Urinary System: Structure and Function of the Nephron

Components of the Nephron

• The nephron is the primary structural unit of the urinary system.

• It consists of two major segments: the Renal Corpuscle and the Renal Tubule.

Renal Corpuscle

• Contains the Glomerulus (a capillary network) and the Glomerular capsule, also referred to as Bowman’s capsule.

• The Glomerulus features fenestrations to facilitate the filtration of blood.

• Associated with the production or regulation of Erythropoietin (EPO) and Renin.

Renal Tubule

• Responsible for processing filtrate through specialized sections:

  • Proximal convoluted tubule.

  • Nephron loop (loop of Henle), consisting of thick and thin descending limbs and thin and thick ascending limbs.

  • Distal convoluted tubule.

• Core functions include:

  • Reabsorption of organic substrates.

  • Reabsorption of approximately $90\%$ of water.

  • Secretion of waste products.

Location and Classification

• Cortical nephron: Characterized by a nephron loop located within the renal cortex.

• Juxtamedullary nephron: Characterized by a nephron loop that extends into the renal medulla.

• Urine eventually flows from the nephron into the renal papilla, major/minor calyces, renal pelvis, and finally the ureter.

Blood Supply to the Nephron

• Blood circulation follows a specific sequence within the nephron environment:

  • Afferent arteriole.

  • Glomerulus capillaries.

  • Efferent arteriole.

  • Peritubular capillaries.

• Additional structures include the Interlobular artery/vein, Arcuate blood vessels, and Interlobar blood vessels.