Kidney Function and Structure

Overview

• Kidneys are bean-shaped organs located below the diaphragm on either side of the spine.
• Main blood vessels (artery and vein) enter the kidneys at the renal pelvis.
• Urine flows from kidneys to the bladder via ureters.

Kidney Structure

• Comprised of:
  • Renal Cortex
  • Renal Medulla
  • Renal Pelvis
• Contains over a million nephrons (functional units).

Nephron Details

• Consists of:
  • Renal Corpuscle: Includes the glomerulus, a cluster of blood vessels encased in a capsule.
  • Tubule: Processes the filtrate.
• Glomerulus:
  • Filters 180 liters of primary urine daily.
  • Retains larger blood components (e.g., red blood cells, large proteins).
  • Primary urine has low molecular weight blood components.

Filtration and Reabsorption

• Nephron's tubules reabsorb water and essential solutes.
• Approximately 1.5 liters of urine are excreted daily.
• Urine contains unnecessary or potentially harmful substances.

Kidney Functions

• Acts as the body's "sewage treatment plant."
• Blood (7 liters) circulates through kidneys over 200 times a day.
• Maintains fluid balance and salt levels.
• Sustains acid-base equilibrium.

Hormonal Functions

• Produces vitamin D.
• Produces hormones:
  • Renin: Regulates blood pressure.
  • Erythropoietin: Stimulates red blood cell production.