Urinary system

• Excretion


  Removal of metabolic waste (waste produced by metabolism)
• Egestion


  Removal of undigested remains (unabsorbed / undigested)
• Secretion


  Release of useful substances from glands / cells
• Homeostasis


  Maintenance of constant internal environment
• Endocrine gland


  • Ductless gland which secretions are released into blood
• Exocrine gland


  • Gland with duct secretions are released into ducts / cavities
• Kidneys


  • Bean-shaped, either side of vertebral column
  • Function: filtering of blood
• Ureter


  • 1 from each kidney
  • Function: deliver urine to bladder
• Bladder


  • Expandable muscular sac closed by sphincter at lower end
  • Function: temporary urine storage
• Urethra


  • Tube that transports urine to exterior (or semen in males)
• Hilum


  Entry for blood vessels, nerves, lymph ducts and ureter
• Adrenal gland


  • Located above each kidney
  • Secretes Aldosterone
• Renal capsule


  • Fibrous connective tissue
  • Enclose / protect kidney
• Cortex


  • Reddish brown outer layer
• Medulla


  • Lighter inner layer
  • Contains renal pyramids
  • Consists of Ducts of Bellini
• Renal pelvis


  Funnel shaped cavity formed by renal calyces, beginning of ureter
• Functions of the kidney:

  − Remove metabolic waste.

  − Osmoregulation -> regulate water content, influenced by ADH & aldosterone, osmoreceptors in

  hypothalamus detect blood water levels.

  − Ionic balance of blood.