Introduction to the Urinary System and Anatomy

Overview

• The urinary system includes:
  • Two kidneys
  • Two ureters
  • One urinary bladder
  • One urethra
• Function: Filters blood, removes metabolic waste, returns water and solutes to the bloodstream.
• Branches of Medicine
  • Nephrology: Function and diseases of the urinary system
  • Urology: Surgical branch related to the urinary system

Anatomy Details

Kidneys

• Right kidney is lower than the left due to liver displacement.
• Located in the posterior part of the peritoneal cavity.
• Surrounded by three layers:
  • Renal Capsule (inner)
  • Adipose Capsule (middle)
  • Renal Fascia (outer)
• Shape and Size:
  • Bean-shaped, about the size of a pack of playing cards
  • Dimensions: 4-5 inches long, 2-3 inches wide
• Protected by floating ribs (11th and 12th ribs)

Ureters

• Connect kidneys to the urinary bladder.
• Pass along the iliac crest and are also retroperitoneal.

Urinary Bladder

• Located behind the pubic symphysis.
• Temporarily stores urine.

Urethra

• In Women: Only for urine release.
• In Men: Transports urine and semen.

Adrenal (Suprarenal) Glands

• Located atop each kidney.
• Rich blood supply.

Physiology

Kidney Functions

• Blood Filtration: Conserves or eliminates water; influences blood volume and concentration of urine.
• Ion Regulation: Balances ion levels in the blood.
• Blood Pressure Regulation:
  • Renin: Hormone affecting filtration rate and resistance.
• pH Balance: Manages hydrogen ions and bicarbonate levels.
• Hormone Production:
  • Erythropoietin: Stimulates red blood cell production.
  • Calcitriol: Active form of Vitamin D.

Waste Removal

• Secretes waste and foreign substances through urine.
• Works with the liver in detoxification.

Pathology

• Thin Individuals: Lack of fat can lead to more mobile kidneys; potential for ureter kinking and blocked urine flow.

Additional Observations

• Transverse Section: Shows relative positions of organs such as liver, kidneys, aorta, and inferior vena cava.