Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Fundamentals of Anatomy & Physiology SIXTH EDITION Frederic H. Martini PowerPoint ® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii Chapter 26, part 2 The Urinary System
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Blood travels from efferent arteriole to peritubular capillaries Vasa recta Renal tubule begins at renal corpuscle Includes glomerulus and Bowman’s capsule Blood leaves the nephron via the efferent arteriole Renal tubule and blood flow
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Podocytes cover lamina densa of capillaries Project into the capsular space Pedicels of podocytes separated by filtration slits Glomerulus anatomy
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.8 The Renal Corpuscle Figure 26.8a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.8 The Renal Corpuscle Figure 26.8c, d
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Proximal convoluted tubule (PCT) Actively reabsorbs nutrients, plasma proteins and ions from filtrate Released into peritubular fluid Loop of Henle Descending limb Ascending limb Each limb has a thick and thin section Functional anatomy of the nephron Animation: Urinary System Anatomy PLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Distal convoluted tubule (DCT) Actively secretes ions, toxins, drugs Reabsorbs sodium ions from tubular fluid Functional anatomy of the nephron Animation: Urinary System Dissection and Flythrough PLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 26-3 Principles of Renal Physiology
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Regulating blood volume and composition Excreting waste products Urea Creatinine Uric acid Urine production maintains homeostasis
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Filtration Blood pressure Water and solutes across glomerular capillaries Reabsorption The removal of water and solutes from the filtrate Secretion Transport of solutes from the peritubular fluid into the tubular fluid Basic processes of urine formation
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Filtration in the kidneys modified by carrier mediated transport Facilitated diffusion Active transport Cotransport Countertransport Carrier proteins have a transport maximum (T m ) Determines renal threshold Carrier Mediated Transport
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Accomplished via diffusion, osmosis, and carrier- mediated transport T m determines renal threshold for reabsorption of substances in tubular fluid Reabsorption and secretion
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Most regions of the nephron perform a combination of functions General functions can be identified Filtration in the renal corpuscle Nutrient reabsorption along the PCT Active secretion at PCT and DCT Loops of Henle regulate final volume and solute concentration Renal function
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.9 An Overview of Urine Formation Figure 26.9
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings SECTION 26-4 Renal Physiology: Filtration and the Glomerulus
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Occurs as fluids move across the glomerulus In response to glomerular hydrostatic pressure (GHP) and blood pressure in the glomerular capillaries Capsular hydrostatic pressure (CsHP) opposes GHP Blood colloid osmotic pressure (BCOP) opposes GHP Net hydrostatic pressure (NHP) = GHP – CsHP Filtration (FP) = NHP – BCOP Filtration pressures - Glomerular filtration
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure Glomerular Filtration Figure 26.10
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure Glomerular Filtration Figure 26.10a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Amount of filtrate produced in the kidneys each minute Factors that alter filtration pressure change GFR Glomerular filtration rate (GFR)
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings A drop in filtration pressure stimulates Juxtaglomerular apparatus (JGA) Releases renin and erythropoietin Factors controlling the GFR
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.11a Figure The Response to a Reduction in the GFR
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.11b Figure The Response to a Reduction in the GFR
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Produces powerful vasoconstriction of afferent arterioles Decreases GFR and slows production of filtrate Changes the regional pattern of blood flow Alters GFR Stimulates release of renin by JGA Sympathetic activation