Figure 24.1 The urinary system. Hepatic veins (cut) Esophagus (cut) Inferior vena cava Renal artery Adrenal gland Renal hilum Aorta Renal vein Kidney Iliac crest Ureter Rectum (cut) Uterus (part of female reproductive system) Urinary bladder Urethra © 2014 Pearson Education, Inc.

Figure 24.2a Position of the kidneys against the posterior body wall. Anterior Inferior vena cava Aorta Peritoneum Peritoneal cavity (organs removed) Supportive tissue layers Renal vein • Renal fascia anterior posterior Renal artery • Perirenal fat capsule • Fibrous capsule Body of vertebra L2 Body wall Posterior © 2014 Pearson Education, Inc.

Figure 24.3a Internal anatomy of the kidney. Renal hilum Renal cortex Renal medulla Major calyx Papilla of pyramid Renal pelvis Minor calyx Ureter Renal pyramid in renal medulla Renal column Fibrous capsule © 2014 Pearson Education, Inc. Photograph of right kidney, frontal section

Figure 24.5 Location and structure of nephrons. (1 of 7) Renal cortex Renal medulla Renal pelvis Ureter Kidney Renal corpuscle • Glomerular capsule • Glomerulus Distal convoluted tubule Proximal convoluted tubule Cortex Medulla Thick segment Thin segment Nephron loop • Descending limb • Ascending limb Collecting duct © 2014 Pearson Education, Inc.

Figure 24.7b Blood vessels of cortical and juxtamedullary nephrons. Peritubular capillary bed Glomerulus Afferent arteriole Efferent arteriole © 2014 Pearson Education, Inc.

Figure 24.6b Renal cortical tissue. Scanning electron micrograph of renal tubules (250x) © 2014 Pearson Education, Inc.

Figure 24.6a Renal cortical tissue. Distal convoluted tubules (clear lumens) Renal corpuscle • Squamous epithelium of parietal layer of glomerular capsule • Glomerular capsular space • Glomerulus Proximal convoluted tubules (fuzzy lumens due to long microvilli) Photomicrograph of renal cortical tissue (180x) © 2014 Pearson Education, Inc.

Figure 24.7b Blood vessels of cortical and juxtamedullary nephrons. Peritubular capillary bed Glomerulus Afferent arteriole Efferent arteriole © 2014 Pearson Education, Inc.

Figure 24.5 Location and structure of nephrons. (1 of 7) Renal cortex Renal medulla Renal pelvis Ureter Kidney Renal corpuscle • Glomerular capsule • Glomerulus Distal convoluted tubule Proximal convoluted tubule Cortex Medulla Thick segment Thin segment Nephron loop • Descending limb • Ascending limb Collecting duct © 2014 Pearson Education, Inc.

Figure 24.8 Juxtaglomerular complex (JGC) of a nephron. capsule Glomerulus Foot processes of podocytes Efferent arteriole Parietal layer of glomerular capsule Podocyte cell body (visceral layer) Capsular space Afferent arteriole Red blood cell Efferent arteriole Proximal tubule cell Juxtaglomerular complex • Macula densa cells of the ascending limb of nephron loop Lumens of glomerular capillaries • Extraglomerular mesangial cells • Granular cells Endothelial cell of glomerular capillary Afferent arteriole Glomerular mesangial cells Juxtaglomerular complex Renal corpuscle © 2014 Pearson Education, Inc.

Figure 24.5 Location and structure of nephrons. (1 of 7) Renal cortex Renal medulla Renal pelvis Ureter Kidney Renal corpuscle • Glomerular capsule • Glomerulus Distal convoluted tubule Proximal convoluted tubule Cortex Medulla Thick segment Thin segment Nephron loop • Descending limb • Ascending limb Collecting duct © 2014 Pearson Education, Inc.

Figure 24.7a Blood vessels of cortical and juxtamedullary nephrons. Cortical nephron Juxtamedullary nephron • Short nephron loop • Glomerulus further from the cortex-medulla junction • Efferent arteriole supplies peritubular capillaries • Long nephron loop • Glomerulus closer to the cortex-medulla junction • Efferent arteriole supplies vasa recta Renal corpuscle Glomerulus (capillaries) Efferent arteriole Cortical radiate vein Glomerular capsule Cortical radiate artery Afferent arteriole Collecting duct Proximal convoluted tubule Distal convoluted tubule Afferent arteriole Efferent arteriole Peritubular capillaries Ascending limb of nephron loop Cortex-medulla junction Arcuate vein Kidney Arcuate artery Vasa recta Nephron loop Descending limb of nephron loop © 2014 Pearson Education, Inc.

1 2 3 1 2 3 Afferent arteriole Glomerular capillaries Figure 24.9 A schematic, uncoiled nephron showing the three major renal processes that adjust plasma composition. Afferent arteriole Glomerular capillaries Efferent arteriole Cortical radiate artery Glomerular capsule 1 Renal tubule and collecting duct containing filtrate Peritubular capillary 2 3 To cortical radiate vein Three major renal processes: Urine 1 Glomerular filtration 2 Tubular reabsorption 3 Tubular secretion © 2014 Pearson Education, Inc.

Figure 24.4b Blood vessels of the kidney. Aorta Inferior vena cava Renal artery Renal vein Segmental artery Interlobar vein Interlobar artery Arcuate vein Arcuate artery Cortical radiate vein Peritubular capillaries or vasa recta Cortical radiate artery Afferent arteriole Efferent arteriole Glomerulus (capillaries) Nephron-associated blood vessels (see Figure 24.7) © 2014 Pearson Education, Inc. (b) Path of blood flow through renal blood vessels

Figure 24.7a Blood vessels of cortical and juxtamedullary nephrons. Cortical nephron Juxtamedullary nephron • Short nephron loop • Glomerulus further from the cortex-medulla junction • Efferent arteriole supplies peritubular capillaries • Long nephron loop • Glomerulus closer to the cortex-medulla junction • Efferent arteriole supplies vasa recta Renal corpuscle Glomerulus (capillaries) Efferent arteriole Cortical radiate vein Glomerular capsule Cortical radiate artery Afferent arteriole Collecting duct Proximal convoluted tubule Distal convoluted tubule Afferent arteriole Efferent arteriole Peritubular capillaries Ascending limb of nephron loop Cortex-medulla junction Arcuate vein Kidney Arcuate artery Vasa recta Nephron loop Descending limb of nephron loop © 2014 Pearson Education, Inc.

Figure 24.11 Forces determining net filtration pressure (NFP). Glomerular capsule Efferent arteriole HPgc = 55 mm Hg OPgc = 30 mm Hg Afferent arteriole HPcs = 15 mm Hg NFP = Net filtration pressure = outward pressures – inward pressures = (HPgc) – (HPcs + OPgc) = (55) – (15 + 30) = 10 mm Hg © 2014 Pearson Education, Inc.

© 2014 Pearson Education, Inc. Figure 24.12 Physiological mechanisms regulating glomerular filtration rate (GFR) in the kidneys. SYSTEMIC BLOOD PRESSURE Blood pressure in afferent arterioles; GFR GFR Granular cells of juxtaglomerular complex of kidney Inhibits baroreceptors in blood vessels of systemic circulation Release Stretch of smooth muscle in walls of afferent arterioles Filtrate flow andNaCl in ascendinglimb of nephron loop Renin Sympathetic nervous system Catalyzes cascade resulting in formation of Targets Vasodilation of afferent arterioles Angiotensin II Macula densa cells of juxtaglomerular complex of kidney Aldosterone secretion by adrenal cortex Vasoconstriction of systemic arterioles; peripheral resistance Release of vasoactive chemicals inhibited Na+ reabsorption by kidney tubules; water follows Vasodilation of afferent arterioles Blood volume GFR Systemic blood pressure Tubuloglomerular mechanism ofautoregulation Myogenic mechanism of autoregulation Hormonal (renin-angiotensin-aldosterone)mechanism Neural controls Intrinsic mechanisms directly regulate GFR despite moderate changes in blood pressure (between 80 and 180 mm Hg mean arterial pressure). Extrinsic mechanisms indirectly regulate GFR by maintaining systemic blood pressure, which drives filtration in the kidneys. © 2014 Pearson Education, Inc.

Figure 24.5 Location and structure of nephrons. (1 of 7) Renal cortex Renal medulla Renal pelvis Ureter Kidney Renal corpuscle • Glomerular capsule • Glomerulus Distal convoluted tubule Proximal convoluted tubule Cortex Medulla Thick segment Thin segment Nephron loop • Descending limb • Ascending limb Collecting duct © 2014 Pearson Education, Inc.

© 2014 Pearson Education, Inc. Figure 24.13 Transcellular and paracellular routes of tubular reabsorption. The transcellular route involves: Filtrate in tubule lumen Tubule cell Interstitial fluid Peri- tubular capillary Transport across the apical membrane. 1 Tight junction Lateral intercellular space Diffusion through the cytosol. 2 3 4 Transport across the basolateral membrane. (Often involves the lateral intercellular spaces because membrane transporters transport ions into these spaces.) 3 H2O and solutes 1 2 3 4 Transcellular route Movement through the interstitial fluid and into the capillary. 4 Apical membrane Capillary endothelial cell The paracellular route involves: Paracellular route • Movement through leaky tight junctions, particularly in the PCT. • Movement through the inter- stitial fluid and into the capillary. H2O and solutes Basolateral membranes © 2014 Pearson Education, Inc.

Figure 24.14 Reabsorption by PCT cells. At the basolateral membrane, Na+ is pumped into the interstitial space by the Na+-K+ ATPase. Active Na+ transport creates concentration gradients that drive: 1 3 Reabsorption of organic nutrients and certain ions by cotransport at the apical membrane. “Downhill” Na+ entry at the apical membrane. 2 Filtrate in tubule lumen Nucleus Interstitial fluid 4 Reabsorption of water by osmosis through aquaporins. Water reabsorption increases the concentration of the solutes that are left behind. These solutes can then be reabsorbed as they move down their gradients: Peri- tubular capillary Tubule cell 2 Glucose Amino acids Some ions Vitamins 1 3 5 Lipid-soluble substances diffuse by the transcellular route. 4 Lipid- soluble substances 5 6 Various ions (e.g., Cl−, Ca2+, K+) and urea diffuse by the paracellular route. Various Ions and urea 6 Tight junction Paracellular route Primary active transport Transport protein Secondary active transport Ion channel Passive transport (diffusion) Aquaporin © 2014 Pearson Education, Inc.