Chapter 26, part 1

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


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


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


SECTION 26-1 An Overview of the Urinary System


• 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


• 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 26.1

Figure 26.1 An introduction to the Urinary System


SECTION 26-2 The Kidneys


• 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


Figure 26.2 The Position of the Kidneys

Figure 26.2a, b

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.3

Figure 26.3 The Urinary System in Gross Dissection


• 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 26.4a, b

Figure 26.4 The Structure of the Kidney


• 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


Figure 26.5 The Blood Supply to the Kidneys

Figure 26.5a, b


Figure 26.5 The Blood Supply to the Kidneys

Figure 26.5c, d


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)


• Nephron empties tubular fluid into collecting system

• Collecting ducts and papillary ducts

Filtrate is produced at the renal corpuscle


Figure 26.6 A Representative Nephron

Figure 26.6


• Production of filtrate

• Reabsorption of organic nutrients

• Reabsorption of water and ions

• Secretion of waste products into tubular fluid

Nephron functions include:


• 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 26.7a

Figure 26.7 Cortical and Juxtamedullary Nephrons

Copyright © 2004 Pearson Education, Inc., publishing as Benjamin Cummings Figure 26.7b, c

Figure 26.7 Cortical and Juxtamedullary Nephrons

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Chapter 26, part 1