Kidney Anatomy and Function

Location and Structure

• Location: Kidneys are located on either side of the spinal column in the posterior abdominal wall.
• Adrenal Glands: Positioned on top of each kidney.

Renal Lobe Composition

• Composed of the medullary pyramid and outer cortex.
• Blood Supply: Branches of the renal artery supply each renal lobe.

Excretory Component: Nephrons

• Smallest branches of the renal artery, called afferent arterioles, supply nephrons.
• Each nephron consists of:
  • Renal Corpuscle
  • Renal Tubule

Urine Production Steps

1. Glomerular Filtration

• Occurs in the renal corpuscle.
• Components:
  • Glomerulus: Network of capillaries.
  • Bowman's Capsule.
• Pressure Dynamics: Afferent arteriole diameter is larger than the efferent arteriole, creating high pressure.
• High pressure forces substances like:
  • Water, nitrogenous waste, amino acids, glucose, sodium ions, and calcium ions into Bowman's capsule.

2. Tubular Reabsorption

• Fluid passes through the renal tubule:
  • Components: Proximal convoluted tubule, Loop of Henle, distal convoluted tubule, and collecting duct.
• Reabsorption:
  • Glucose, amino acids, some sodium, and calcium ions reabsorbed actively into peritubular capillaries.
  • Water reabsorbed via osmosis.

3. Tubular Secretion

• Occurs primarily in the distal convoluted tubules.
• Processes:
  • Larger nitrogenous wastes, excess hydrogen ions, and potassium ions extracted from peritubular capillaries.
  • These are secreted into the tubular fluid.

Conclusion

• After secretion, waste products continue through the urinary system and are excreted from the body as urine.