Human Anatomy-Urinary System

PowerPoint® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham 23 HUMAN ANATOMY fifth edition PART 1 The Urinary System MARIEB | MALLATT | WILHELM Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Urinary System  Important functions of the kidneys  Maintain the chemical consistency of blood  Filter many liters of fluid from blood  Send toxins, metabolic wastes, and excess water out of the body  Main waste products  Urea  Uric acid  Creatinine Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Organs of the Urinary System     Kidneys Ureters Urinary bladder Urethra Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.1a Location and External Anatomy of Kidneys  Located retroperitoneally  Lateral to T12–L3 vertebrae  Average kidney  12 cm tall, 6 cm wide, 3 cm thick  Hilus  On concave surface  Vessels and nerves enter and exit  Renal capsule surrounds the kidney Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Relationship of the Kidneys to Vertebra and Ribs Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.1b Position of the Kidneys with in the Posterior Abdominal Wall Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.2a Internal Gross Anatomy of the Kidneys  Frontal section through the kidney  Renal cortex  Renal pyramids  Renal pelvis  Major calicies  Minor calicies  Gross vasculature  Renal arteries  Branch into segmental arteries Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Summary of Blood Vessels Supplying the Kidney Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.3c Internal Gross Anatomy of the Kidneys  Nerve supply – renal plexus  A network of autonomic fibers  An offshoot of the celiac plexus Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Internal Anatomy of the Kidneys Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.3b Microscopic Anatomy of the Kidneys  Uriniferous tubules  Composed of  Nephron  Renal corpuscle plus renal tubules  Collecting duct  Involved in concentrating urine PLAY Nephron Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Mechanisms of Urine Production  Filtration  Filtrate of blood leaves kidney capillaries  Reabsorption  Most nutrients, water, and essential ions reclaimed  Secretion  Active process of removing undesirable molecules Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Basic Kidney Functions Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.4 PowerPoint® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham 23 HUMAN ANATOMY fifth edition PART 2 The Urinary System MARIEB | MALLATT | WILHELM Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Uriniferous Tubule Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.5a The Nephron  Renal corpuscle  Glomerulus and glomerular capsule  Glomerulus – tuft of capillaries  Capillaries of glomerulus are fenestrated  Glomerular (Bowman’s) capsule  Parietal layer – simple squamous epithelium  Visceral layer – consists of podocytes Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Renal Corpuscle and the Filtration Membrane Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.6a Renal Corpuscle and the Filtration Membrane Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.6c Tubular Section of Nephron  Filtrate proceeds to renal tubules from glomerulus  Proximal convoluted tubule  Loop of Henle  Descending limb  Thin segment  Thick segment  Distal convoluted tubule Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Micrograph through the Renal Medulla Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.7 Classes of Nephron  Cortical nephrons  85% of nephrons  Juxtamedullary nephrons  15% of nephrons Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Collecting Tubules (Collecting ducts)  Collecting tubules  Receive urine from distal convoluted tubules Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.8 Classes of Nephron Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.9a Microscopic Blood Vessels  Nephrons associated with two types of capillary beds (a portal system)  Glomerulus  Fed and drained by arterioles  Afferent and efferent arterioles  Peritubular capillaries  Arise from efferent arterioles  Low-pressure, porous capillaries  Absorb solutes Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Blood Vessels  Vasa recta  Thin-walled looping vessels  Part of the kidney’s urine-concentrating mechanism Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint® Lecture Slides prepared by Leslie Hendon, University of Alabama, Birmingham 23 HUMAN ANATOMY fifth edition PART 3 The Urinary System MARIEB | MALLATT | WILHELM Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Anatomy of the Kidney  Juxtaglomerular apparatus  Functions in the regulation of blood pressure  Juxtaglomerular cells – secrete renin  Macula densa  A portion of distal convoluted tubule  Tall, closely packed epithelial cells  Act as chemoreceptors Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Juxtaglomerular Apparatus Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.10 Ureters  Carry urine from the kidneys to the urinary   bladder Oblique entry into bladder prevents backflow of urine Histology of ureter  Mucosa – transitional epithelium  Muscularis – two layers  Inner longitudinal layer  Outer circular layer  Adventitia – typical connective tissue Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Microscopic Structure of the Ureter Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.12 Urinary Bladder  A collapsible muscular  sac Stores and expels urine  Full bladder – spherical  Expands into the abdominal cavity  Empty bladder – lies entirely within the pelvis Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.13 Urinary Bladder  Urachus – closed  remnant of the allantois Prostate gland  In males  Lies directly inferior to the bladder  Surrounds the urethra Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.14 Urinary Bladder  Wall of bladder  Mucosa  Transitional epithelium  Muscular layer  Detrus or muscle  Adventitia Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Histology of the Urinary Bladder Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.15a, b Structure of the Urinary Bladder and Urethra Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.16a Structure of the Urinary Bladder and Urethra Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.16b Urethra  Epithelium of urethra  Transitional epithelium  At the proximal end (near the bladder)  Stratified and pseudostratified columnar – mid urethra (in males)  Stratified squamous epithelium  At the distal end (near the urethral opening) Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Urethra  Internal urethral sphincter  Involuntary smooth muscle  External urethral sphincter  Voluntarily inhibits urination  Relaxes when one urinates Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Urethra  In females  In males – 20 cm in length – three named regions  Prostatic urethra  Membranous urethra  Passes through the prostate gland  Length of 3–4 cm  Spongy (penile) urethra  Through the urogenital diaphragm  Passes through the length of the penis Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Micturition Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.17 Disorders of the Urinary System  Urinary tract infections  Renal calculi  More common in females  Burning sensation during micturition  Kidney stones  Bladder cancer  Kidney cancer  3% of cancers – more common in men  Arises from epithelial cells of uriniferous tubules Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings The Urinary System Throughout Life  Embryo develops three pairs of kidneys  Pronephros  Mesonephros  Metanephros  Only metanephros persists to become the adult kidneys  Metanephric kidney produces urine by fetal month three  Contributes to the volume of amniotic fluid Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Development of the Urinary Organs Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.18a,b Development of the Urinary Organs Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings Figure 23.18c, d The Urinary System Throughout Life  Kidney and bladder function declines with advancing age  Nephrons decrease in size and number  Tubules less efficient at secretion and reabsorption  Filtration declines  Recognition of desire to urinate is delayed  Loss of muscle tone in the bladder Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings