Urinary System: Outcome: I can describe the specific filtration process kidneys use for blood. Drill: What are the four main structures/organs in the urinary system?

Nephron Collecting System Figure 24.4 1 – 2 2 4 Proximal Convoluted Overview of a nephron and the collecting system Slide 1 Nephron Collecting System 2 4 Proximal Convoluted Tubule Distal Convoluted Tubule Renal tubule 1 Renal Corpuscle Efferent arteriole 5 Collecting Duct Afferent arteriole Glomerular capsule Descending limb of loop begins Ascending limb of loop ends Capsular space Glomerulus 3 Ascending limb Nephron Loop 6 Papillary Duct KEY Filtrate Water reabsorption Variable water reabsorption Solute reabsorption or secretion Descending limb Variable solute reabsorption or secretion © 2015 Pearson Education, Inc. Figure 24.4 1 – 2

Renal cortex Cortical nephron Juxtamedullary nephron Renal medulla Types of nephrons and their location Renal cortex Cortical nephron Juxtamedullary nephron Renal medulla Minor calyx © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Figure 24.3 3

Segments of a Nephron Nephron components Two components Renal corpuscle Blood pressure forces water and solutes out of the glomerular capillaries in a process called filtration Produces filtrate (protein-free solution, similar to blood plasma) Renal tubule Tubular passageway Receives filtrate and modifies it to create urine © 2015 Pearson Education, Inc.

Segments of a Nephron Nephron segments Renal corpuscle Glomerular capsule (cup-shaped chamber) Capillary network (glomerulus) Proximal convoluted tubule (PCT) Reabsorbs nutrients from the filtrate (now called tubular fluid) © 2015 Pearson Education, Inc.

Segments of a Nephron Nephron segments (continued) Nephron loop (Loop of Henle) Establishes osmotic gradient for water reabsorption Each limb contains a thin segment and a thick segment Distal convoluted tubule (DCT) Adjusts tubular fluid composition by reabsorption and secretion © 2015 Pearson Education, Inc.

Nephron Figure 24.4 1 2 4 Proximal Convoluted Tubule Distal Convoluted Parts of a nephron Nephron 2 4 Proximal Convoluted Tubule Distal Convoluted Tubule Renal tubule 1 Renal Corpuscle Efferent arteriole Afferent arteriole Glomerular capsule Descending limb of loop begins Ascending limb of loop ends Capsular space Glomerulus 3 Ascending limb Nephron Loop KEY Filtrate Water reabsorption Variable water reabsorption Solute reabsorption or secretion Descending limb Variable solute reabsorption or secretion © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Figure 24.4 1

Circulation Patterns in the Kidney Blood flow around a nephron Afferent arteriole Supplies blood to each individual nephron Glomerulus (FILTRATION OCCURS HERE) Efferent arteriole Carries blood from the glomerulus to the peritubular capillaries Peritubular capillaries (in Cortical Nephron) Vasa Recta (in Juxtmedullary Nephron) Surround the entire renal tubule Collect water and solutes absorbed by the nephron Deliver other solutes to the nephron for secretion Drain into cortical radiate veins © 2015 Pearson Education, Inc.

Glomerular capsule Capsular space Initial segment of renal tubule Cross-sectional view of the visceral layer of the glomerular capsule Glomerular capsule Capsular space Initial segment of renal tubule Efferent arteriole DCT Juxtaglomerular complex Parietal layer Visceral layer Visceral layer Afferent arteriole Glomerular endothelial cell Mesangial cells Filtration slits RBC Pedicels Podocyte Capsular space © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Figure 24.8 1 – 2

Peritubular capillaries Peritubular capillaries in a cortical nephron Glomerulus in renal corpuscle Peritubular capillaries Efferent arteriole Afferent arteriole To the cortical radiate vein © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Figure 24.5 2

Peritubular capillaries Vasa recta in a juxtamedullary nephron Peritubular capillaries Efferent arteriole Afferent arteriole To cortical radiate vein Capillaries of the vasa recta © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Figure 24.5 3

Urine storage and elimination Locations of filtration, reabsorption, and secretion in the nephron and collecting system Proximal convoluted tubule (PCT) Distal convoluted tubule (DCT) Glomerulus KEY Filtration Water reabsorption Variable water reabsorption Glomerular capsule Collecting duct Solute reabsorption Variable solute reabsorption or secretion Nephron loop © 2015 Pearson Education, Inc. © 2015 Pearson Education, Inc. Urine storage and elimination Figure 24.7 1

Glomerular Filtration Rate Glomerular filtration rate (GFR) Amount of filtrate produced by the kidneys each minute Each kidney has ~6 m2 (64 sq. ft.) of filtration surface GFR averages 125 mL/min (180 L/day) ~99 percent is reabsorbed © 2015 Pearson Education, Inc.

Urinary System: Exit Ticket: Describe the pathway of blood flow into the kidney. What arteries are being pass through (in order)?