PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Tenth Edition Shier ...
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Transcript of PowerPoint Lecture Outlines to accompany Hole’s Human Anatomy and Physiology Tenth Edition Shier ...
PowerPoint Lecture Outlines to accompany
Hole’s HumanAnatomy and Physiology
Tenth Edition
Shier Butler Lewis
Chapter
20
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 20-1
Chapter 20Urinary System
20-2
Location of Kidneys
20-3
Kidneys
20-4
Renal Blood Vessels
20-5
Renal Blood Vessels
20-6
Glomerular Capsule
20-7
Nephron and Associated Blood Vessels
20-8
Renal Cortex and Renal Medulla
20-9
Juxtaglomerular Apparatus
20-10
Types of Nephrons
• cortical nephrons• 80% of nephrons
• juxtamedullary nephrons• regulate water balance
20-11
Blood Supply of Nephron
The capillary loop of the vasa recta is closely associated with the nephron loop of the juxtamedullary nephron
20-12
Summary of Blood Flow Through Kidney and Nephron
20-13
Urine Formation
• Glomerular Filtration• substances move from blood to glomerular capsule
• Tubular Reabsorption• substances move from renal tubules into blood of peritubular capillaries• glucose, water, urea, proteins, creatine• amino, lactic, citric, and uric acids• phosphate, sulfate, calcium, potassium, and sodium ions
• Tubular Secretion• substances move from blood of peritubular capillaries into renal tubules• drugs and ions
20-14
Glomerular Filtration
Glomerular filtrate passes through the fenestrae of the capillary endothelium
20-15
Glomerular Filtrate and Urine Composition
20-16
Glomerular Filtration Rate
Net Filtration Pressure = force favoring filtration – forces opposing filtration (glomerular capillary ( capsular hydrostatic pressure hydrostatic pressure) and glomerular capillary osmotic pressure )
20-17
Amounts of Glomerular Filtrate and Urine
average amounts over a 24 hour period
20-18
Control of Filtration Rate
• Increased sympathetic impulses decrease GFR by causing afferent arterioles to constrict• Renin-angiotensin system (shown)• Autoregulation
20-19
Tubular Reabsorption
20-20
Tubular Reabsorption of Water and Ions
20-21
Sodium and Water Filtration, Reabsorption, and Excretion
20-22
Tubular Secretion
20-23
Secretion of Ions
In distal convoluted tubules, potassium ions or hydrogen ions may be passively secreted in response to active reabsorption of sodium ions
20-24
Countercurrent Mechanism• helps maintain the NaCl concentration gradient in the medullary interstitial fluid
20-25
Countercurrent Mechanism of Vasa Recta
• fluid in ascending limb becomes hypotonic as solute is reabsorbed• fluid in descending limb becomes hypertonic as it loses water by osmosis
20-26
Effect of ADH on Renal Tubules
• without ADH, DCT and collecting duct are impermeable to water• with ADH, DCT and collecting duct become permeable to water• with ADH, water is reabsorbed by osmosis into hypertonic medullary interstitial fluid
20-27
Urea and Uric Acid Excretion
Urea• product of amino acid catabolism• plasma concentration reflects the amount or protein in diet• enters renal tubules through glomerular filtration• 50% reabsorbed• rest is excreted
Uric Acid• product of nucleic acid metabolism• enters renal tubules through glomerular filtration• 100% reabsorbed• 10% secreted and excreted
20-28
Renal Clearance
• the rate at which a chemical is removed from the plasma• tests of renal clearance
• inulin clearance test• creatinine clearance test• paraminohipparic acid test
• tests of renal clearance used to calculate glomerular filtration rate
20-29
Elimination of Urine
• nephrons• collecting ducts• renal papillae• minor and major calyces• renal pelvis• ureters• urinary bladder• urethra• outside world
20-30
Ureters
• 25 cm long• extend downward posterior to the parietal peritoneum• parallel to vertebral column• in pelvic cavity, join urinary bladder• wall of ureter
• mucous coat• muscular coat• fibrous coat
20-31
Location of Male and Female Urinary Bladders
20-32
Urinary Bladder
Longitudinal section and posterior view of male urinary bladder
20-33
Cross Section of Urethra
20-34
Male and Female Urethras
20-35
Micturition
• bladder distends and stretch receptors stimulated• micturition center activated in sacral portion of spinal cord• parasympathetic nerve impulses cause detrusor muscle to contract• need to urinate is sensed
• voluntary contraction of external urethral sphincter prevents urination
• when decision is made to urinate, external urethral sphincter relaxes, detrusor muscle contracts, and urine is expelled
20-36
Life-Span Changes
• kidneys appear scarred and grainy • kidney cells die• by age 80, kidneys have lost a third of their mass• kidney shrinkage due to loss of glomeruli• proteinuria may develop• renal tubules thicken• harder for kidneys to clear certain substances• bladder, ureters, and urethra lose elasticity• bladder holds less urine
20-37
Clinical Application
Glomerulonephritis
• inflammation of glomeruli• may be acute or chronic• acute glomerulonephritis usually occurs as an immune reaction to a Streptococcus infection• antigen-antibody complexes deposited in glomeruli and cause inflammation• most patients recover from acute glomerulonephritis• chronic glomerulonephritis is a progressive disease and often involves diseases other than that caused by Streptococcus• renal failure may result from chronic glomerulonephritis
20-38