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Home , Arcuate vein, Detrusor muscle, Efferent arteriole, Renal column, Renal corpuscle, Renal cortex

Tips for Success 1. Show up 2. Participate in lab 3. Show up 4. Turn in assignments (completed, refer to #6) 5. Show up 6. Communicate with me, e-mail is best 7. Show up

Every point counts! Business  Homework due in lab  Label the handout provided today  Front and back  Use your book!  There should be at least 18 items labeled Part 1  Wastes  Gases versus fluids  Urinary system  Dispose of water soluble wastes  Electrolyte regulation  Acid-base regulation

Urinary System  Other functions  Kidneys   Vitamin D activation Nitrogenous Wastes  is about 95% water  Second largest component is  Urea derived from breakdown of amino acids

Nitrogenous Wastes TOXIC! + 1. Dietary amino acids → NH2 removed → NH2 + H → NH3  500 ml of urine removes only 1 gram of nitrogen as ammonia 2. Ammonia can be converted to urea  Requires energy  50 ml of urine removes 1 gram of nitrogen as urea 3. Ammonia can be converted to uric acid  Requires lots of energy  10 ml of urine removes 1 gram of nitrogen as uric acid

Urinary System  Organs  Kidneys  Major excretory organs   Temporary storage reservoir for urine   Transport urine from the kidneys to the bladder   Transports urine out of the body Hepatic (cut) Esophagus (cut) Inferior vena cava Renal Aorta Renal Iliac crest

Rectum (cut) Uterus (part of female reproductive Urinary system) bladder Urethra

Figure 25.1 Kidney: Urinary System page 6

Anterior Inferior vena cava

Peritoneal cavity Aorta Peritoneum (organs removed) Supportive tissue layers • anterior Renal posterior artery • Perirenal fat capsule Body of • Fibrous vertebra L2 capsule Body wall (a) Posterior

Figure 25.2a Kidneys  Retroperitoneal position  External anatomy  Hilus  3 tissue layers  Fibrous capsule  Perirenal fat capsule  Renal fascia

Hydronephrosis Kidneys  Internal Anatomy  Renal  Superficial region  Renal columns extend into medulla

Kidneys   Cone-shaped medullary (renal) pyramids separated by the renal columns  Renal  Funnel-shaped tube, contain calyces  Continuous with ureter

Kidneys

 Internal Anatomy  Minor calyces  Major calyces  Branching channels of the  Collect urine from minor calyces  Empty urine into the pelvis  Urine flows from the pelvis to ureter Renal hilum

Renal cortex

Renal medulla

Major calyx Papilla of pyramid Renal pelvis

Minor calyx Ureter

Renal pyramid in renal medulla

Fibrous capsule

(a) Photograph of right kidney, frontal section (b) Diagrammatic view

Figure 25.3 Kidneys  Blood Supply  Renal deliver ~ 22 % of cardiac output (1.2 L/min)  90% directed to cortex  Urine formation Cortical radiate vein Cortical radiate artery Arcuate artery Interlobar vein Interlobar artery Segmental arteries Renal vein Renal pelvis

Ureter

Renal medulla

Renal cortex

(a) Frontal section illustrating major blood vessels

Figure 25.4a Aorta Inferior vena cava

Renal artery Renal vein

Segmental artery Interlobar vein

Interlobar artery Arcuate vein

Cortical radiate Arcuate artery vein

Peritubular Cortical radiate artery and Afferent arteriole (capillaries)

Nephron-associated blood vessels (see Figure 25.7) (b) Path of blood flow through renal blood vessels

Figure 25.4b  Structural and functional units that form urine  ~1 million per kidney  Two main parts 1. Blood capillaries (glomeruli) 2. Renal tubule: begins as cup-shaped glomerular (Bowman’s) capsule surrounding the glomerulus Figure 25.5 Nephrons   Glomerulus + Bowman’s capsule  Fenestrated glomerular endothelium  Allows filtrate to pass from plasma into the glomerular capsule Efferent Glomerular capsule arteriole Glomerulus

Afferent arteriole Foot processes Parietal layer of of glomerular cell capsule body (visceral Capsular layer) space Red blood cell Efferent Proximal arteriole tubule cell

Juxtaglomerular apparatus • cells of the ascending limb Lumens of of glomerular • Extraglomerular capillaries mesangial cells Endothelial cell • Granular cells of glomerular Afferent arteriole Mesangial cells between capillaries

Juxtaglomerular Renal corpuscle apparatus

Copyright © 2010 Pearson Education, Inc. Figure 25.8 Cortical Juxtamedullary nephron • Has short loop of Henle and glomerulus • Has long loop of Henle and glomerulus further from the corticomedullary junction closer to the corticomedullary junction • Efferent arteriole supplies peritubular • Efferent arteriole supplies vasa recta capillaries Efferent arteriole Cortical radiate vein Renal Glomerular capillaries Cortical radiate artery corpuscle (glomerulus) Afferent arteriole Glomerular Collecting duct (Bowman’s) capsule Proximal Afferent arteriole convoluted tubule Efferent arteriole Ascending or thick limb of the loop of Henle Corticomedullary Arcuate vein junction Arcuate artery Vasa recta Cortex Loop of Henle Medulla Renal pelvis Descending Ureter or thin limb of loop of Henle Kidney

(a)

Copyright © 2010 Pearson Education, Inc. Figure 25.7a Nephrons  Renal tubules  Proximal convoluted tubule (PCT)  Functions in reabsorption and secretion  Confined to the cortex  Loop of Henle  Descending and ascending limbs  Distal convoluted tubule (DCT)  Function more in secretion than reabsorption  Confined to the cortex

Nephrons  Renal tubules  Collecting tubules (CT)  Receive filtrate from many nephrons  Fuse together to deliver urine through papillae into minor calyces Glomerular capsule: parietal layer Renal cortex Basement Renal medulla membrane Renal corpuscle Podocyte • Glomerular capsule Renal pelvis Fenestrated • Glomerulus endothelium Distal of the glomerulus Ureter convoluted Glomerular capsule: visceral layer tubule Kidney Microvilli Mitochondria

Proximal convoluted tubule Highly infolded plasma membrane Cortex Proximal convoluted tubule cells

Medulla

Thick segment Distal convoluted tubule cells Thin segment Loop of Henle • Descending limb • Ascending limb Collecting Loop of Henle (thin-segment) cells duct Principal cell Intercalated cell

Collecting duct cells

Copyright © 2010 Pearson Education, Inc. Figure 25.5 Nephrons  Juxtaglomerular Apparatus (JGA)  Ascending limb of loop of Henle and afferent arteriole contact one another  One per nephron  Function  Regulation of filtrate formation and Efferent Glomerular capsule arteriole Glomerulus

Afferent arteriole Foot processes Parietal layer of podocytes of glomerular Podocyte cell capsule body (visceral Capsular layer) space Red blood cell Efferent Proximal arteriole tubule cell

Juxtaglomerular apparatus • Macula densa cells of the ascending limb Lumens of of loop of Henle glomerular • Extraglomerular capillaries mesangial cells Endothelial cell • Granular cells of glomerular capillary Afferent arteriole Mesangial cells between capillaries

Juxtaglomerular Renal corpuscle apparatus

Copyright © 2010 Pearson Education, Inc. Figure 25.8 Nephron Capillary Beds 1. Glomerulus  Afferent arteriole  glomerulus  efferent arteriole  Specialized for Nephron Capillary Beds 2. Peritubular capillaries  Low-pressure, porous capillaries adapted for absorption  Arise from efferent arterioles  Cling to adjacent renal tubules in cortex  Empty into venules Cortical nephron Juxtamedullary nephron • Has short loop of Henle and glomerulus • Has long loop of Henle and glomerulus further from the corticomedullary junction closer to the corticomedullary junction • Efferent arteriole supplies peritubular • Efferent arteriole supplies vasa recta capillaries Efferent arteriole Cortical radiate vein Renal Glomerular capillaries Cortical radiate artery corpuscle (glomerulus) Afferent arteriole Glomerular Collecting duct (Bowman’s) capsule Distal convoluted tubule Proximal Afferent arteriole convoluted tubule Efferent arteriole Peritubular capillaries Ascending or thick limb of the loop of Henle Corticomedullary Arcuate vein junction Arcuate artery Vasa recta Cortex Loop of Henle Medulla Renal pelvis Descending Ureter or thin limb of loop of Henle Kidney

(a)

Copyright © 2010 Pearson Education, Inc. Figure 25.7a Nephrons  Cortical nephrons  85% of nephrons; almost entirely in the cortex  Juxtamedullary nephrons  Long loops of Henle deeply invade the medulla  Extensive thin segments  Important in the production of concentrated urine Cortical nephron Juxtamedullary nephron • Has short loop of Henle and glomerulus • Has long loop of Henle and glomerulus further from the corticomedullary junction closer to the corticomedullary junction • Efferent arteriole supplies peritubular • Efferent arteriole supplies vasa recta capillaries Efferent arteriole Cortical radiate vein Renal Glomerular capillaries Cortical radiate artery corpuscle (glomerulus) Afferent arteriole Glomerular Collecting duct (Bowman’s) capsule Distal convoluted tubule Proximal Afferent arteriole convoluted tubule Efferent arteriole Peritubular capillaries Ascending or thick limb of the loop of Henle Corticomedullary Arcuate vein junction Arcuate artery Vasa recta Cortex Loop of Henle Medulla Renal pelvis Descending Ureter or thin limb of loop of Henle Kidney

(a)

Copyright © 2010 Pearson Education, Inc. Figure 25.7a Ureters  Convey urine from kidneys to bladder  Retroperitoneal location  Enter base of bladder through posterior wall  ↑ bladder pressure = distal ends of the ureters close  Prevents backflow of urine  Mucus is protective Urinary Bladder  Muscular sac for temporary storage of urine  On pelvic floor posterior to pubic symphysis  Males— gland surrounds the neck inferiorly  Females—anterior to the and uterus

Urinary Bladder  Stretch receptors in bladder create desire to void  Micturition  Urge to void usually occurs with about 300ml urine  Can hold up to about 500ml

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 Urinary system) bladder Urethra

Figure 25.1 Urethra  Sphincters  Internal  CNS control  External  Voluntary control

Peritoneum Ureter Rugae Ureteric orifices Bladder neck Internal urethral sphincter Trigone External urethral sphincter Urogenital diaphragm Urethra External urethral (b) Female. orifice

Copyright © 2010 Pearson Education, Inc. Figure 25.21b Peritoneum Ureter Rugae Detrusor muscle Ureteric orifices Trigone of bladder Bladder neck Internal urethral sphincter Prostate Urogenital diaphragm External urethral sphincter

Spongy urethra Erectile tissue of penis External urethral orifice

(a) Male. The long male urethra has three regions: prostatic, membranous and spongy.

Copyright © 2010 Pearson Education, Inc. Figure 25.21a Brain Higher brain Urinary bladder centers filling stretches bladder wall Allow or inhibit micturition as appropriate

Afferent impulses Pontine micturition Pontine storage from stretch center center receptors

Simple Promotes micturition Inhibits micturition spinal by acting on all three by acting on all three reflex spinal efferents spinal efferents

Spinal Spinal cord cord

Parasympathetic Sympathetic Somatic motor Parasympathetic activity activity activity activity Sympathetic activity Somatic motor nerve activity

Detrusor muscle contracts; internal External urethral urethral sphincter sphincter opens opens

Inhibits Micturition

Copyright © 2010 Pearson Education, Inc. Figure 25.22 Incontinence  Damage to spinal cord  Frequent micturition in infants  Incontinence is normal: control of the voluntary urethral sphincter develops with the nervous system

Pathway of Urine Flow

Urine formed in nephrons  calyces  renal pelvis  ureters bladder  urethra

Activity  Draw and label the major organs of the urinary system  Kidneys (and adrenal glands), ureters, bladder and urethra