Introduction

• The urinary system is a system of organs, tubes, muscles, and nerves that work together to create, store, and carry, urine. The urinary system includes two kidneys, two ureters, the urinary bladder, two sphincter muscles, and the urethra.
• Functions of the Urinary System:

  1. Removing toxins from the body.
  2. Maintain the proper balance of water, salts, and acids in the body fluids.
  3. The kidneys also act as endocrine organs, secreting hormones into the bloodstream.
• Urea is a waste that is produced when protein foods combine with oxygen and from nitrogenous waste. Urea is formed in the liver from ammonia, which is derived from the breakdown of simple proteins.
• The Kidney:

  • Because it is crowded by the liver, the right kidney is positioned slightly lower than the left.
  • Each kidney is surrounded by perirenal fat and pararenal fat or adipose capsule that help cushion it.
  • Para- (adjacent or near), Peri- (around)
• The Kidney:

  • Because it is crowded by the liver, the right kidney is positioned slightly lower than the left.
  • Each kidney is surrounded by perirenal fat and pararenal fat or adipose capsule that help cushion it.
  • Para- (adjacent or near), Peri- (around)
• If the amount of fatty tissue dwindles (as with rapid weight loss), the kidneys may drop to a lower position, This condition is called ptosis (to’sis, a fall).
• If the amount of fatty tissue dwindles the kidneys may drop to a lower position. This condition is called ptosis (a fall). Ptosis creates problem if the ureters become kinked (twisted).
• When urine that usually passes through the ureters backs up and exerts effort on the kidney tissue, it is called hydronephrosis.
• Structure of Kidney:

  1. Renal cortex (outer region)
  2. Renal medulla (inner middle region)
  3. Renal artery
  4. Renal vein
• The ureters are slender tubes, each 25 to 30 cm long and 6 cm in diameter.

  • LOCATION: Each ureter runs behind the peritoneum from the hilum of a kidney to the posterior aspect of the bladder.
  • STRUCTURE: The superior end of each ureter is continuous with the pelvis of the kidney and its mucosa lining is continuous with that lining the renal pelvis and the bladder below.
• Function of Kidney:

  • The ureters are passageway that carry urine from kidney to the bladder.
  • The smooth muscle layers in the walls of the ureters contract to push urine into the bladder by peristalsis. Peristalsis is the involuntary muscle movement that moves food through your gastrointestinal tract.
  • Once urine entered the bladder, it is prevented from flowing backwards into the ureter by small valve-like folds of bladder mucosa.
• When urine becomes extremely concentrated, solutes such as uric acid salts form crystals that precipitate in the renal pelvis. These crystals are called renal calculi or kidney stones.
• Noninvasive procedure such as lithotripsy is being used to shatter the calculi using ultrasound waves.
• Lithotripsy involves the administration of a series of shock waves to the targeted stone.
• The bladder, an expandable hollow organ, acts as a temporary reservoir for urine. When empty, the small folds called rugae that allow expansion as it fills.
• At the interior of the bladder are 3 openings:

  • Two ureter openings
  • Single opening of the urethra.

  At the base of the bladder is a triangular area called trigone.
• The urethra is a thin-walled tube that carries urine by peristalsis from the bladder to the outside of the body.
• Micturition or voiding is the act of emptying the bladder. During voiding, urine is expelled through the urethral opening, the urinary meatus.
• Incontinence occurs when we are unable to voluntarily control the external sphincter.
• Urinary retention is the opposite of incontinence. It is a condition in which the bladder is unable to expel its contained urine.
• Causes of urinary retention:

  1. After undergoing surgery
  2. Enlargement of the prostate gland (hypertrophy).