Blood Supply to the Kidneys

Introduction

• The kidneys are crucial for filtering blood.
• Understanding kidney function requires knowledge of their blood supply.
• Focus: Blood flow to, through, and from the kidneys back to the heart.

The Aorta and Renal Arteries

• Aorta: Major vessel leaving the heart.
  • Travels through thoracic and abdominal regions.
  • Sends off branches to different parts of the body.
• Abdominal Aorta:
  • Branches include the renal arteries.
• Renal Arteries:
  • Two branches: Left and right renal arteries.
  • Supply approximately 20% of the blood leaving the heart.
  • Direct blood to the kidneys.

Blood Flow Through the Kidneys

• Segmental Arteries:
  • Branch from renal arteries to different kidney sections.
• Interlobar Arteries:
  • Branch from segmental arteries, travel between kidney "lobes" or pyramids.
• Arcuate Arteries:
  • Form arches around pyramids.
• Interlobular Arteries:
  • Further branching from arcuate arteries.
  • Lead to afferent arterioles.

Nephrons and Filtration

• Afferent Arterioles:
  • Lead into nephrons, the kidney's functional units.
• Glomerulus:
  • Site of blood filtration.
  • Blood exits via efferent arterioles.
• Peritubular Capillaries:
  • Extensive capillary network following the glomerulus.

Blood Exit from the Kidneys

• Veins in the Kidney:
  • Mirror the names of arteries.
  • Interlobular Veins: Begin the venous return.
  • Arcuate and Interlobar Veins: Follow next in the sequence.
  • Renal Veins: Final stage, drain into the inferior vena cava.
  • Note: Some textbooks include segmental veins in the sequence.

Summary

• Blood travels from the heart via the aorta, through renal arteries, and reaches the nephrons.
• After filtration, blood exits through a series of veins, returning to the heart via the inferior vena cava.

Next Steps

• Future video to cover nephron structure and function in detail.