Chapter 26 Urinary 2016(1).ppt - Chapter 26 Urinary System The Urinary System 2 Kidneys 2 Ureters Urinary Bladder and the Urethra Kidney Functions 1

Chapter 26 Urinary System

The Urinary System 2 Kidneys, 2 Ureters, Urinary Bladder, and the Urethra

Kidney Functions 1. Regulates blood ion composition ( Na + , K + , Ca 2+ ) 2. Regulates blood pH , excretes H + and conserve HCO 3 - 3. Regulates blood volume , conserve or eliminate H 2 O 4. Regulates blood pressure , renin increases BP 5. Regulates blood glucose , gluconeogenesis , the synthesis of glucose using amino acid glutamine 6. Maintains blood osmolarity , by regulating H 2 O and ions 7. Produces hormones , (renin and erythropoietin ) 8. Excretes wastes ( urea, bilirubin and creatinine ) *Also, has a role in synthesizing Vitamin D (calcitriol) to control calcium levels, detoxifies free radicals and drugs

Excretion • Separation of wastes from body fluids and eliminating them; by four systems – respiratory : CO 2 – integumentary : water, salts, lactic acid, urea – digestive : water, salts, CO 2 , lipids, bile pigments, cholesterol – urinary : many metabolic wastes, toxins, drugs, hormones, salts, H + and water

Anatomy of Kidney • Position, weight and size – retroperitoneal, level of T12 to L3 – about 160 g each – about size of a bar of soap (12x6x3 cm) • Nephron – functional unit of the kidney • Shape – lateral surface - convex; medial - concave • Connective tissue coverings – renal fascia : binds to abdominal wall – adipose (perinephric fat)capsule : cushions kidney – renal (fibrous)capsule : like visceral pericardium

Kidney Location Perirenal Fat

Kidney Anatomy Renal Capsule Hilum Cortex Medulla Columns Pyramids Papilla Minor calyx Major calyx Pelves

Path of Blood Through Kidney • Renal artery  segmental arteries  interlobar arteries (up renal columns, between lobes)  arcuate arteries (over pyramids)  cortical radiate (interlobular) arteries (up into cortex)  afferent arterioles  glomerulus (cluster of capillaries)  efferent arterioles (near medulla  vasa recta)  peritubular capillaries  cortical radiate veins  arcuate veins  interlobar veins  renal vein

Blood Supply Diagram

Microcirculation of Kidney cortical radiate cortical radiate

Nephron Glomerular capsule

Parietal vs Visceral

Renal Corpuscle

Filtration Membrane

Filtration Membrane Kidney disease or in some cases strenuous exercise can allow the larger proteins and even RBCs into urine, known as proteinuria and hematuria , respectively • Fenestrated endothelium – excludes blood cells • Basement membrane – negative charge excludes proteins • Filtration slits – allow particles < 3nm (glucose, fatty acids, electrolytes)

4 Segments Proximal Convoluted Tubule (PCT) Nephron Loop -Thin segment -Thick segment Distal Convoluted Tubule (DCT) Collecting Duct -Papillary duct

Functional Anatomy

Nitrogenous Wastes • Urea CO(NH 2 ) 2 – Proteins  amino acids  NH 2 removed  forms ammonia, liver converts to urea • Uric acid – nucleic acid catabolism • Creatinine – creatine phosphate catabolism • Renal failure – azotemia :  BUN (blood urea nitrogen), nitrogenous wastes in blood – uremia : toxic effects as wastes accumulate