Anatomy of the Kidney

• Location of the Kidneys

  the bean shaped kidneys lie in a retroperitoneal position between the dorsal body wall + the parietal peritoneum in the superior lumbar region

  extending from T2 to L3, the kidneys receive some protection from the lower part of the rib cage
• External Anatomy

  the lateral surface = convex

  medial surface = concave

  has a vertical cleft called the renal hilum that leads into an internal space called the renal sinus

  the ureter, renal blood vessels, lymphatics + nerves all join each kidney at the hilium + occupy the sinus

  atop each kidney = adrenal glands, an edocrine gland

  
• Surrounding Supportive Layers of the Kidneys - Renal Fascia

  renal fascia = an outer layer of dense fibrous connective tissue that anchors the kidney + the adrenal gland to surrounding structures
• Surrounding Supportive Layers of the Kidneys - Perirenal Fat Capsule

  perirenal fat capsule = fatty mass that surrounds the kidney + cushions it against blunt trauma
• Surrounding Supportive Layers of the Kidneys - Fibrous Capsule

  the fibrous capsule = transparent capsule that prevents infections in surrounding regions from spreading to the kidney
• Internal Gross Anatomy


  the kidney has 3 internal regions:

  cortex

  medula

  pelvis

  
• Renal Cortex


  the most superficial region, lighter in colour

  contains the initial portons of the neprhons where blood filtration begins

  
• Renal Medulla


  deep to the cortex is the darker renal medulla

  exhibits cone-shaped tissue masses called renal pyramids

  = formed mostly of parallel bundles of microscopic urine collecting tubules + capillaries

  the renal columns, inward extensions of cortical tissue, separate the pyramids

  
• Renal Pelvis


  the renal pelvis = funnel-shaped tube

  continous w the ureter leaving the hilium

  branching extensions of the pelvis form 2/3 major calyces

  = collect urine, which drains continously from the papillae + empty it into the renal pelvis

  the walls of the calyces, pelvis + ureter contain smooth muscle that contracts rhythmically to propel urine by peristalsis