Anatomy of the Kidneys

Anatomy of the Kidneys

• Human kidneys are located below the diaphragm, on either side of the vertebral column in the abdominal cavity.
• The right kidney is slightly smaller and positioned lower than the left kidney.
• Kidneys are dark brown, bean-shaped organs, featuring both a concave and a convex side.
• The concave side faces the vertebral column, with a notable area called the hilus where the renal artery enters and the renal vein and ureter exit.
• Each kidney is encased in a protective tissue known as the renal capsule.

Structural Regions of the Kidney

• A longitudinal section reveals two distinct regions: the renal cortex (outer region) and the renal medulla (inner region).
• The renal medulla contains cone-shaped structures known as renal pyramids, with their bases facing the cortex and tips leading to a cavity called the renal pelvis.
• The renal pelvis is a funnel-like structure that extends to form the ureter, connecting to the urinary bladder.

Functional Units of the Kidney

• Nephrons serve as the functional units of the kidneys, with each kidney containing over one million nephrons.
• Each nephron consists of two main parts: the renal corpuscle and the renal tubule.

Components of the Nephron

• Renal Corpuscle: Comprises the glomerulus (a network of capillaries) encased in the Bowman's capsule (cup-shaped structure surrounding the glomerulus).

• Renal Tubule: A long tubular structure attached to the Bowman's capsule, divided into three parts:

  • Proximal Convoluted Tubule: The first segment, highly convoluted to enhance absorption.
  • Loop of Henle: U-shaped section functioning in concentration of urine.
  • Distal Convoluted Tubule: The final convoluted part that leads to the collecting duct.

• Many distal convoluted tubules from various nephrons converge into a single collecting duct, which facilitates urine transport.