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Chapter 19, part A. The Kidneys. About this Chapter. Anatomy of the excretory system How the kidney is organized How the nephron works to filter blood, recycle, secrete, and excrete How filtration is regulated Urination reflex. Kidney Functions: Overview.
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Chapter 19, part A The Kidneys
About this Chapter • Anatomy of the excretory system • How the kidney is organized • How the nephron works to filter blood, recycle, secrete, and excrete • How filtration is regulated • Urination reflex
Kidney Functions: Overview • Homeostatic regulation: ECF volume, osmolarity, ion & pH balance • Excretion: Metabolic wastes & foreign molecules • Regulating hormones & enzymes
Kidney Functions: Overview Figure 19-3: The excretion of a substance depends on the amount that was filtered, reabsorbed, and secreted
Excretory System: Anatomy Review • Kidney • Cortex • Medulla • Pelvis • Nephrons • Ureter • Bladder • Urethra Figure 19-1: Anatomy Summary: The Urinary System
Nephron Functions: Overview • Filtration, reabsorption, secretion & excretion
Nephron Functions: Overview Figure 19-2: Filtration, reabsorption, secretion, and excretion
Glomerulus & Bowman's Capsule: Blood Filtration • Capillaries • Podocytes • Mesanglial cells • Bulk flow • Solutes • Water • (Few proteins) • (Not cells)
Glomerulus & Bowman's Capsule: Blood Filtration Figure 19-4: Structure of the renal corpuscle
Glomerular Flow Rate (GFR) • Capillary • Hydrostatic pressure • Colloidal • Capsule pressure • Back pressure • Net Filtration p • GFR 180L/day (about 1% is excreted) Figure 19-6: Filtration pressure in the renal corpuscle
Glomerular Flow Rate (GFR) Figure 19-5: The filtration fraction
Regulation of GFR • Autoregulation • Myogenic stretch • Tubuloglomerular feedback • Macula densa • J G cells • ANS-Sympathetic • Arteriole vasoconstriction • Hormones/paracrines • Angiotensin II • Prostaglandins
Regulation of GFR Figure 19-9: The juxtaglomerular apparatus