Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Fundamentals of
Anatomy & PhysiologySIXTH EDITION
Frederic H
. Martini
PowerPoint® Lecture Slide Presentation prepared by Dr. Kathleen A. Ireland, Biology Instructor, Seabury Hall, Maui, Hawaii
Chapter 26, part 1
The Urinary System
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Learning Objectives
• Identify the components and functions of the urinary system
• Describe the location and structural features of the kidneys
• Describe the structure of a nephron, and outline the processes involved in the formation of urine
• Describe the normal characteristics, composition, and solute concentrations of a representative urine sample
Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings
Learning Objectives
• List and describe the factors that influence filtration pressure and the rate of filtrate formation
• Identify the types of transport mechanisms found along the nephron
• Describe how antidiuretic hormone and aldosterone levels influence the volume and concentration of urine
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SECTION 26-1 An Overview of the Urinary System
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• 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
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• The kidneys
• Produce urine
• The ureters
• The urinary bladder
• Stores urine
• The urethra
Urinary system includes:
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Figure 26.1 An introduction to the Urinary System
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SECTION 26-2 The Kidneys
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• 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
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Figure 26.2 The Position of the Kidneys
Figure 26.2a, b
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Figure 26.3 The Urinary System in Gross Dissection
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• 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
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Figure 26.4 The Structure of the Kidney
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• 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
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Figure 26.5 The Blood Supply to the Kidneys
Figure 26.5a, b
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Figure 26.5 The Blood Supply to the Kidneys
Figure 26.5c, d
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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)
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• Nephron empties tubular fluid into collecting system
• Collecting ducts and papillary ducts
Filtrate is produced at the renal corpuscle
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Figure 26.6 A Representative Nephron
Figure 26.6
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• Production of filtrate
• Reabsorption of organic nutrients
• Reabsorption of water and ions
• Secretion of waste products into tubular fluid
Nephron functions include:
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• 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
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Figure 26.7 Cortical and Juxtamedullary Nephrons
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Figure 26.7 Cortical and Juxtamedullary Nephrons