The urinary system consists of the kidneys, ureters, urinary bladder, and urethra. The kidneys filter the blood to remove wastes and produce urine. The urine travels from the kidneys down the ureters into the urinary bladder, where it is stored until emptying through the urethra. The nephrons are the functional units of the kidney that filter the blood and regulate water and electrolyte balance to produce urine and maintain homeostasis. Common disorders of the urinary system include renal failure, cystitis, kidney stones, and urinary incontinence.

1. The URInary
System

2. Organs of the Urinary System
Kidneys
Ureter
Urinary Bladder
Urethra

3. Kidneys
Bean-shaped organ located between the 12th thoracic
and 3rd lumbar vertebrae in the flank area
Divided into the cortex (outer layer) and medulla
(middle portion)
Concave border has a notch called the hilum where the
renal artery, vein, nerves and lymphatic vessels enter.
The ureter starts at the hilum
Contains the nephrons (functional units of the kidney)

9. Nephron
Microscopic
1 million in each kidney
Divided into the renal corpuscle (glomerulus &
Bowman’s capsule) and tubule (proximal
convoluted tubule, descending loop of Henle,
ascending loop of Henle, distal convoluted
tubule, collecting duct)

11. Functions of the Nephron
Removes the wastes products (urea, nitrogen, uric acid
& creatinine) of metabolism from the 1.5 million mL of
blood that pass through each kidney every day
Maintain fluid balance by regulating the amount of
fluid and electrolytes reabsorbed through the tubules
into the blood and excreted into the tubules in the urine
Micturition/Production of 1,000-1,500 ml of clear,
straw colored, and mildly aromatic urine daily with a
gravity of 1.003-1.050 and a pH of 6
Concentrate the urine when the person is dehydrated
and dilute the urine when the person is overhydrated

15. Ureters
Two muscular tubes that carry the urine from
each kidney to the bladder

17. Urinary Bladder
Muscular sac in the pelvic cavity that stores the
urine
Can hold up to 500 mL of urine when its wall
stretches

19. Urethra
Musculomembranous tube transporting the
urine from the bladder to the urinary meatus
Has an internal sphincter and an external
sphincter

21. Urine Formation
Glomerular Filtration : All the small molecules
(glucose, amino acids & uric acid) except the blood
cells and plasma protein in the blood pass through the
pores of the capillaries (glomerulus) into the
Bowman’s capsule to form the glomerular filtrate
Tubular Reabsorption : 99% of the water that passed
through the pores are reabsorbed through the tubules
into the capillaries surrounding the tubules. Useful
substances like glucose and salt (NaCl) are also
reabsorbed in the proximal convoluted tubule
Tubular Secretion : Medications and other
substances

24. Common Disorders Associated
with the Urinary System
Renal Failure : When the kidney ceases
functioning

25. Cystitis : Inflammation of the bladder. Causes
frequency and dysuria

27. Glomerulonephritis : Inflammation of the
glomeruli

30. Kidney Stones : Renal calculi caused by
deposits of mineral salts in the kidney

33. Polycystic Kidney Disease : Cluster of cysts
developing in the kidneys

35. Pyelonephritis : Infection of the kidney and
renal pelvis

37. Urinary Incontinence : Involuntary and
unpredictable flow of urine

38. The
End