Urinary System

• Structures that make up the urinary system: Kidney, Uterus, Bladder, Urethra
• Structures that go in and out of the hilum: Renal Vein, Ureter, Nerves, Lymphatics
• Papillary ducts empty urine into calyces. Calyces pass urine to the ureter
• What filters blood plasma?

  Renal Corpuscle
• Renal Tubule = Modifies the filtrate
• Nephron has these structures:

  • Renal Capsule - Production of filtrate
  • Proximal Convoluted tubule - Reabsorption of water ions, and all organic nutrients
  • Distal Convoluted Tubule - secretions of ions, acids, drugs, toxins
  • Collecting Duct - Variable reabsorption of water and reabsorption or secretion of sodium, potassium, hydrogen, and bicarbonate ions
  • Papillary duct - delivery of urine to minor calyx
  • Loop of Henle - Further reabsorption of water and both sodium and chloride ions
• Glomerulus = A mass of capillaries, fed by the Afferent Arteriole and drained by the Efferent Arteriole
• Podocytes = Specialized cells found in the Bowman's capsule, part of the kidney's filtration system, located in the glomerulus
• The glomerulus in the kidney has tiny holes in its blood vessels, a filter-like layer, special cells called podocytes with slits, and other cells that help control blood flow, all working together to filter blood and make urine
• Components of Juxtaglomerular Apparatus:

  • Juxtaglomerular Cells - rings of smooth muscles in the Afferent arterioles where the latter enters Bowman's capsule
  • Macula Densa - specialized tubule cells of the distal tubule
• Juxtaglomerular Apparatus = Produces site of renin production
• Principal Cells = Receptors for ADH and aldosterone
• Intercalated Cells = Help to manage blood pH
• Glomerular Filtration is Driven by blood pressure
• Glomerular Filtration Rate = Amount of filtrate formed by both kidneys each minute, maintained by homeostasis
• ADH = in its presence, collecting ducts become very permeable to water, making tubular fluid very concentrated
• Abnormalities evaluated in urinalysis = Albumin, Glucose, RBCs, Ketone Bodies, Microbes
• the ureter transports urine = By peristaltic waves, hydrostatic pressure and gravity, from the renal pelvis