7.1a Nephrology - Kidney and Nephron Overview - video 1

Overview of the Kidneys

• Location and Structure
  • Situated in the abdominal cavity.
  • Each person has two kidneys; the left kidney is slightly higher than the right.
  • Above the kidneys are the adrenal glands, which secrete hormones.
• Function of Kidneys
  • Produce urine, which moves through the ureter to the urethra and is expelled by the body.
  • Regulate blood pH, volume, and composition.
  • Eliminate nitrogenous waste via urine.
• Blood Supply
  • Renal Artery: Supplies blood to kidneys.
  • Inferior Vena Cava: Brings blood back to the heart.

Kidney Anatomy

• Sections of the Kidney
  • Renal Cortex: The outer part.
  • Renal Medulla: The inner part containing the renal pyramids.
  • Renal Pelvis: Connects to the ureter.

Nephrons: Functional Unit of the Kidneys

• Importance
  • Each kidney has approximately 1 to 1.5 million nephrons.
  • Responsible for filtration, reabsorption, and secretion to form urine.
• Structure
  • Renal Corpuscle: Composed of the glomerulus and Bowman’s capsule.
  • Proximal Convoluted Tubule: First section; important for reabsorption with cuboidal cells having microvilli.
  • Loop of Henle: Consists of descending and ascending loops; important for concentration gradients.
  • Distal Convoluted Tubule: Final section before the collecting duct.
  • Collecting Duct: Transports urine to the ureter.

Types of Nephrons

• Juxtamedullary Nephrons
  • Long Loop of Henle; extends deep into the medulla.
  • Contains vasa recta, important for concentrating urine.
• Cortical Nephrons
  • Short loop of Henle; primarily located in the cortex.

Physiological Processes

• Filtration
  • Occurs at the glomerulus.
  • Afferent arterioles bring blood to the nephron; efferent arterioles take filtered blood away.
• Reabsorption and Secretion
  • Takes place along different segments of the nephron.
  • Vasa recta plays a key role in water reabsorption.
• Cell Types in Nephrons
  • Collecting Duct: Cuboidal, principal, and intercalated cells.
  • Loop of Henle: Thin epithelial-like cells.
  • Distal Tubule: Regular cuboidal cells.
  • Proximal Tubule: Cuboidal cells with microvilli.

Blood Flow Pathways

• Blood enters through the renal artery and is filtered by the glomerulus.
• Leaves via efferent arterioles, forming the renal vein.
• Vasa recta helps in maintaining osmotic gradients necessary for kidney function.

Wrap-up

• Understanding of kidney anatomy and function is crucial to comprehend how they regulate important body functions.
• Future discussions will cover nephron physiology and additional kidney functions.

Conclusion

• For further learning and engagement, subscribe to Arando Huran Biology and Medicine videos, and participate in discussions on their Facebook page.