Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture prepared by Kathleen A. Ireland, Seabury Hall, Maui, Hawaii Anatomy & Physiology M A R T I N I FIRST EDITION C h a p t e r 26 The Urinary System PowerPoint® Lecture Slides prepared by Jason LaPres Lone Star College - North Harris Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Excretion The removal of organic waste products from body fluids Elimination The discharge of waste products into the environment Homeostatic regulation of blood plasma Regulating blood volume and pressure Regulating plasma ion concentrations Stabilizing blood pH Conserving nutrients Functions of the urinary system
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The kidneys Produce urine The ureters The urinary bladder Stores urine The urethra Urinary system includes:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.1 Figure 24.1 An introduction to the Urinary System
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Left kidney extends slightly more superiorly than right Both kidneys and adrenal glands are retroperitoneal Hilus Entry for renal artery and renal nerves Exit for renal veins and ureter The kidneys
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.2 The Position of the Kidneys Figure 24.2a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.3 Figure 24.3 The Urinary System in Gross Dissection
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Superficial outer cortex and inner medulla The medulla consists of 6-18 renal pyramids The cortex is composed of roughly 1.25 million nephrons Major and minor calyces along with the pelvis drain urine to the ureters Sectional anatomy of the kidneys
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.4a, b Figure 24.4 The Structure of the Kidney
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Renal arteries branch repeated Renal artery Segmental artery Interlobar artery Arcuate artery Interlobular artery Afferent arterioles Renal venules follow similar opposing pattern ending with renal veins Blood supply and innervation of the kidneys
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.5 The Blood Supply to the Kidneys Figure 24.5a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.5 The Blood Supply to the Kidneys Figure 24.5c, d
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The nephron consists of a renal corpuscle and renal tubule The renal corpuscle is composed of Bowman’s capsule and the glomerulus The renal tubule consists of Proximal convoluted tubule (PCT) Loop of Henle Distal convoluted tubule (DCT)
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Nephron empties tubular fluid into collecting system Collecting ducts and papillary ducts Filtrate is produced at the renal corpuscle
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.6 A Representative Nephron Figure 24.6
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Production of filtrate Reabsorption of organic nutrients Reabsorption of water and ions Secretion of waste products into tubular fluid Nephron functions include:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Cortical nephrons ~85% of all nephrons Located in the cortex Juxtamedullary nephrons Closer to renal medulla Loops of Henle extend deep into renal pyramids Two types of nephron
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.7a Figure 24.7 Cortical and Juxtamedullary Nephrons
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.7b, c Figure 24.7 Cortical and Juxtamedullary Nephrons
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 24.8 The Renal Corpuscle Figure 24.8a, b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.8 The Renal Corpuscle Figure 24.8c, 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 PLAY Animation: Urinary system anatomy
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
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 24.9 An Overview of Urine Formation Figure 24.9
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 24.10a, 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 24.11a Figure The Response to a Reduction in the GFR
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.11b 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
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Glomerular filtration produces fluid similar to plasma without proteins The PCT reabsorbs 60-70% of the filtrate produced Reabsorption of most organic nutrients Active and passive reabsorption of sodium and other ions Reabsorption of water Secretion also occurs in the PCT Reabsorption and secretion at the PCT PLAY Animation: Glomerular filtration PLAY Animation: Early filtrate processing
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure Transport Activities at the PCT Figure Animation: Proximal convoluted tubule PLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The loop of Henle and countercurrent multiplication Countercurrent multiplication Between ascending and descending limbs of loop Creates osmotic gradient in medulla Facilitates reabsorption of water and solutes before the DCT Permits passive reabsorption of water from tubular fluid
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.13a Figure Countercurrent Multiplication and Concentration of Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.13b, c Figure Countercurrent Multiplication and Concentration of Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings DCT performs final adjustment of urine Active secretion or absorption Absorption Tubular cells actively resorb Na + and Cl - In exchange for potassium or hydrogen ions (secreted) Reabsorption and secretion at the DCT
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.14a, b Figure Tubular Secretion and Solute Reabsorption at the DCT Animation: Distal convoluted tubule PLAY
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure c Figure Tubular Secretion and Solute Reabsorption at the DCT
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Reabsorption and secretion along the collecting system Water and solute loss is regulated by aldosterone and ADH Reabsorption Sodium ion, bicarbonate, and urea are resorbed Secretion pH is controlled by secretion of hydrogen or bicarbonate ions
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Control of urine volume and osmotic concentration Urine volume and osmotic concentration are regulated by controlling water reabsorption Precise control allowed via facultative water reabsorption
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.15a, b Figure The Effects of ADH on the DCT and Collecting Ducts
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Removes solutes and water Balances solute reabsorption and osmosis in the medulla Function of the vasa recta
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Varies with the metabolic and hormonal events of the body Reflects filtration, absorption and secretion activity of the nephrons Urinalysis is the chemical and physical analysis of urine Composition of normal urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Each segment of nephron and collecting system contribute Glomerulus PCT Descending limb Thick ascending limb DCT and collecting ducts Concentrated urine produced after considerable modification of filtrate Summary of renal function: PLAY Animation: Late filtrate processing
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure A Summary of Renal Function Figure 24.16a
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure A Summary of Renal Function Figure 24.16b
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Urine production ends with fluid entering the renal pelvis Rest of urinary system transports, stores and eliminates Ureters Bladder Urethra
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure Figure A Radiographic View of the Urinary System
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Pair of muscular tubes Extend from renal pelvis to the bladder Peristaltic contractions force urine toward the urinary bladder The ureters
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Hollow, muscular organ Reservoir for the storage of urine Contraction of detrusor muscle voids bladder Internal features include Trigone Neck Internal urethral sphincter Ruggae The urinary bladder
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.19a Figure Organs for the Collection and storage of Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.19b Figure Organs for the Collection and storage of Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.19c Figure Organs for the Collection and storage of Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Extends from the urinary bladder to the exterior of the body Passes through urogenital diaphragm (external urinary sphincter) Differs in length and function in males and females The urethra
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.20a Figure The Histology of the Organs that Collect and Transport Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 24.20b, c Figure The Histology of the Organs that Collect and Transport Urine
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Urination coordinated by micturition reflex Initiated by stretch receptors in wall of bladder Urination requires coupling micturition reflex with relaxation of external urethral sphincter Micturition reflex and urination
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure The Micturition Reflex Figure 24.21
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The components of the urinary system and their functions The location and structural features of the kidneys The structure of a nephron, and the processes involved in the formation of urine The normal characteristics, composition, and solute concentrations of a representative urine sample You should now be familiar with:
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings The factors that influence filtration pressure and the rate of filtrate formation The types of transport mechanisms found along the nephron How antidiuretic hormone and aldosterone levels influence the volume and concentration of urine You should now be familiar with: