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Urinary System Review Questions:
1. This system would be lined with what type of membrane?2. What type of epithelial tissue would line the opening of the urethra (the exit of the tract)?3. What type of epithelial tissue would line the majority of the tract?4. What type of muscle would line the walls of this tract?5. What parasympathetic nerve would supply the urinary system? Hint: We’re below the hips!
Functions
Influences blood pressure (Renin)
Controls pH
Removes excesses
Activates Vitamin D
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Body wall
• Perirenal fat capsule
Renalartery
Renalvein
Inferiorvena cavaAorta
• Fibrous (True) capsule
• Renal fascia anterior posterior
Supportivetissue layers
Body ofvertebra L2
PeritoneumPeritoneal cavity(organs removed)
Anterior
Posterior
12th rib
(b)
(a)
956
T12-L3Adrenal glandHilum
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Renal cortex
Renal medulla
Major calyx
Papilla ofpyramid
Renal pelvis
Ureter
Minor calyx
Renal column
Renal pyramid in renal medulla
Fibrous capsule
Renalhilum
(b) Diagrammatic view
filtering
Salt, collecting ducts
957
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Cortical radiate vein Cortical radiate arteryArcuate veinArcuate arteryInterlobar veinInterlobar arterySegmental arteries
Renal artery
Renal vein
Renal pelvis
Ureter
Renal medulla
Renal cortex
(a) Frontal section illustrating major blood vessels958
(Interlobular)(Interlobular)
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Aorta
Renal artery
Segmental artery
Interlobar artery
Arcuate artery
Cortical radiate artery
Afferent arteriole
Glomerulus (capillaries)
Nephron-associated blood vessels(see Figure 25.7)
Inferior vena cava
Renal vein
Interlobar vein
Arcuate vein
Cortical radiatevein
Peritubularcapillaries
and vasa recta
Efferent arteriole
(b) Path of blood flow through renal blood vessels958
Interlobular
Interlobular
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Cortical nephron Juxtamedullary nephron
Corticomedullaryjunction
UreterRenal pelvis
Kidney
CortexMedulla
(a)
Cortical radiate veinCortical radiate arteryAfferent arteriole
Afferent arteriole
Collecting ductDistal convoluted tubule
Efferent arteriole
Vasa rectaLoop of HenleArcuate arteryArcuate vein
Peritubular capillaries
Glomerular capillaries (glomerulus)
Glomerular(Bowman’s) capsule
Renalcorpuscle
Ascending or thick limb of the loop of Henle
Descendingor thin limb of loop of Henle
Efferent arteriole
Proximalconvoluted tubule
961
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Fenestratedendotheliumof the glomerulus
Microvilli
Cortex
Medulla
Podocyte
Basementmembrane
Mitochondria
Highly infolded plasmamembrane
Proximalconvolutedtubule
Distalconvolutedtubule
• Descending limbLoop of Henle
• Ascending limb
• Glomerular capsuleRenal corpuscle
• Glomerulus
Thick segment
Collectingduct
Intercalated cellPrincipal cell
Thin segment
Proximal convoluted tubule cells
Glomerular capsule: parietal layer
Glomerular capsule: visceral layer
Distal convoluted tubule cells
Loop of Henle (thin-segment) cells
Collecting duct cells
Renal cortex
Renal medulla
Renal pelvis
Ureter
Kidney
959
The Nephron
absorption
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Glomerular capillarycovered by podocyte-containing visceral layer of glomerular (Bowman’s) capsule
Glomerular capillaryendothelium (podocyte covering and basement membrane removed)
Proximalconvolutedtubule
Parietal layerof glomerular Capsule(Bowman’s)
Afferentarteriole
Glomerularcapsular space
Fenestrations(pores)
Efferentarteriole
Podocytecell body
Foot processesof podocyte
Filtration slits
Cytoplasmic extensionsof podocytes
(a) Glomerular capillaries and the visceral layer of the glomerular capsule
964
Renal corpuscle
filtrate
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GlomerulusGlomerular capsule
Afferent arteriole
Efferent arteriole
Red blood cell
Podocyte cell body (visceral layer)
Foot processesof podocytesParietal layer
of glomerularcapsule
Proximaltubule cell
Lumens of glomerularcapillaries
Endothelial cellof glomerularcapillary
Efferent arteriole
• Macula densa cells of the ascending limb of loop of Henle
• Granular cells
• Extraglomerular mesangial cells
Afferent arteriole
Capsularspace
Renal corpuscleJuxtaglomerularapparatus
Mesangial cellsbetween capillaries
Juxtaglomerularapparatus
962
DCT
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Esophagus (cut)Inferior vena cava
Adrenal gland
Hepatic veins (cut)
Renal artery
Renal hilum
Renal vein
Iliac crestKidney
Ureter
Urinarybladder
Urethra
Aorta
Rectum (cut)Uterus (part of female reproductive system)
955
Retroperitoneal
-Fibrous CT-Smooth muscle circular longitudinal-Transitional Ep.
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Ureter
Trigone of bladder
Prostate
Membranous urethra
Prostatic urethra
Peritoneum
RugaeDetrusor muscle
Bladder neckInternal urethral sphincter
External urethral sphincterUrogenital diaphragm
Spongy urethraErectile tissue of penis
Ureteric orificesAdventitia
(a) Male. The long male urethra has three regions: prostatic, membranous and spongy.
External urethral orifice
981
Below Peritoneum(Holding Chamber)
Transitional Ep.3 layers
Mucous membrane & Submucosa
Micturition Reflex (para.)
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Ureter
Trigone
Peritoneum
RugaeDetrusor muscle
Bladder neckInternal urethralsphincterExternal urethralsphincter
Urogenital diaphragm
UrethraExternal urethralorifice
Ureteric orifices
(b) Female.
1.5”3 layers-mucosa-spongy-sm. muscleCystitis
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Corticalradiateartery
Afferent arteriole
Glomerular capillaries
Efferent arteriole
Glomerular capsule
Rest of renal tubulecontaining filtrate
Peritubularcapillary
To cortical radiate vein
Urine
Glomerular filtrationTubular reabsorptionTubular secretion
Three majorrenal processes:
963
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Glomerularcapsule
Afferentarteriole
10 mm Hg
Netfiltrationpressure
Glomerular (blood) hydrostatic pressure(HPg = 55 mm Hg) out
Blood colloid osmotic pressure(Opg = 30 mm Hg) in
Capsular hydrostatic pressure(HPc = 15 mm Hg) in
965
Net Filtration PressureNFP= (BHP-CHP)-BOP
Glomerular filtration rate(120 ml/min)
Myogenic Autoregulation-increased stretch causes constriction-decreased stretch causes dilation
Sympathetic stim.
Copyright © 2010 Pearson Education, Inc.
GlomerulusGlomerular capsule
Afferent arteriole
Efferent arteriole
Red blood cell
Podocyte cell body (visceral layer)
Foot processesof podocytesParietal layer
of glomerularcapsule
Proximaltubule cell
Lumens of glomerularcapillaries
Endothelial cellof glomerularcapillary
Efferent arteriole
• Macula densa cells of the ascending limb of loop of Henle (DCT)
• Granular cells(JG cells)
• Extraglomerular mesangial cells
Afferent arteriole
Capsularspace
Renal corpuscleJuxtaglomerularapparatus
Mesangial cellsbetween capillaries
Juxtaglomerularapparatus
962
Monitors NaCl in filtrate at DCT
High filtrate production= more NaClLow filtrate production= less NaCl
Macula Densa
High Flow Low Flow(high NaCl) (low NaCl)
JG (granular) cells JG (granular) cells-vasoconstrictor to -vasodilator toafferent arteriole afferent arteriole
-Renin
Decreases BHP at glom. Increases BHP at glom.and filtrate production and increases filtrate
production
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Figure 19.10 Direct and indirect (hormonal) mechanisms for renal control of blood pressure.
Direct renal mechanism Indirect renal mechanism (renin-angiotensin-aldosterone)
Arterial pressure Arterial pressure
Inhibits baroreceptors
Sympathetic nervoussystem activity
Renin releasefrom kidneys
Angiotensinogen
Angiotensin I
Angiotensin II
Angiotensin convertingenzyme (ACE)
Urine formation
Filtration by kidneys
Blood volume
Adrenal cortex ADH release byposterior pituitary
Secretes
Aldosterone
Sodium reabsorption by kidneys
Water reabsorption by kidneys
Water intake
Blood volume
Mean arterial pressure
Vasoconstriction;peripheral resistance
Thirst viahypothalamus
Mean arterial pressure
Initial stimulus
Physiological response
Result
708
Granular cells
Copyright © 2010 Pearson Education, Inc.
Stretch of atriaof heart due to BP
Atrial natriuretic peptide (ANP)
Adrenal cortexHypothalamusand posterior
pituitary
Collecting ductsof kidneys
JG apparatusof the kidney
ADH release Aldosterone release
Na+ and H2O reabsorption
Blood volume
Vasodilation
Renin release*
Blood pressure
Releases
Negativefeedback
Targets
Effects
Effects
Inhibits
Effects
Inhibits
Results in
Results in
Angiotensin II
1001
Make more urine
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At the basolateral membrane, Na+ is pumped into the interstitial space by the Na+-K+
ATPase. Active Na+ transport creates concentration gradients that drive:
“Downhill” Na+ entry at theluminal membrane.
Reabsorption of water byosmosis. Water reabsorptionincreases the concentration of the solutes that are left behind. These solutes can then be reabsorbed asthey move down their concentration gradients:
Reabsorption of organic nutrients and certain ions by cotransport at the luminal membrane.
Lipid-solublesubstances diffuse by the transcellular route.
Cl– (and other anions), K+, and urea diffuse by the paracellular route.
Filtratein tubulelumen
GlucoseAmino acidsSome ionsVitamins
Lipid-solublesubstances
Nucleus
Tubule cell
Paracellularroute
Interstitialfluid
Peri-tubular
capillary
Tight junction
Primary active transport
Passive transport (diffusion) Secondary active transport
Transport protein
Ion channel or aquaporin
Cl–, Ca2+, K+
and otherions, urea
Cl–
3Na+
2K+
3Na+
2K+
K+
H2O
Na+
6
5
4
3
2
1
1
2
3
4
5
6
970
80% of reabsorption in PCT
obligatory
Renal Plasma Threshold
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Loop of Henle
Osmolalityof interstitialfluid(mOsm)
Innermedulla
Outermedulla
Cortex Active transport
Passive transport
Water impermeable
(a) Countercurrent multiplier. The long loops of Henle of the juxtamedullary nephrons create the medullary osmotic gradient.
The ascending limb:• Impermeable to H2O• Permeable to NaClFiltrate becomes increasingly dilute as NaCl leaves, eventually becoming hypo-osmotic to blood at 100 mOsm in the cortex. NaCl leaving the ascending limb increases the osmolality of the medullary interstitial fluid.
Filtrate entering the loop of Henle is isosmotic to both blood plasma and cortical interstitial fluid.
The descending limb:• Permeable to H2O• Impermeable to NaClAs filtrate flows, it becomes increasingly concentrated as H2Oleaves the tubule by osmosis. The filtrate osmolality increases from 300 to 1200 mOsm.
H2O
H2O
H2O
H2O
H2O
H2O
H2O
NaCI
NaCI
NaCI
NaCI
NaCI
975
Obligatory reabsorption into vasa recta (peritubular capillaries)
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Active transport
Passive transport
Small volume ofconcentrated urine
Cortex
NaCI
NaCI
NaCI Urea
Urea
H2O
H2O
H2O
H2O
H2O
H2O
H2O
Outermedulla
Innermedulla
(b) Maximal ADH
DCT
Descending limbof loop of Henle
Collecting duct
H2O
H2O
977
Water channels inserted in collecting duct (facultative reabsorption)
Caffeine & Alcohol
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Cortex
Outermedulla
Innermedulla
(a)
(b)
(c)
(e)
(d)
Na+ (65%)GlucoseAmino acids
H2O (65%) and many ions (e.g.Cl– and K+)
300
Milliosmols
600
1200
Blood pH regulation
H+,NH4
+
HCO3–
Somedrugs
Active transport(primary or secondary)Passive transport
(a) Proximal convoluted tubule: • 65% of filtrate volume reabsorbed • Na+, glucose, amino acids, and other nutrients actively transported; H2O and many ions follow passively • H+ and NH4
+ secretion and HCO3– reabsorption to
maintain blood pH (see Chapter 26) • Some drugs are secreted
973
Tubular Secretion
PenicillinHistamine
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Blood pHregulation
Urea;increasedby ADH
Na+
K+
H+
HCO3–
NH4+
H2O regulatedby ADH
Regulated byaldosterone:
(e) Collecting duct • H2O reabsorption through aquaporins regulated by ADH • Na+ reabsorption and K+ secretion regulated by aldosterone • H+ and HCO3
– reabsorption or secretion to maintain blood pH (see Chapter 26) • Urea reabsorption increased by ADH
(a)
(b)
(c)
(e)
(d)
Cortex
Outermedulla
Innermedulla
300
Milliosmols
600
1200
Active transport(primary or secondary) Passive transport
973
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OsmolalityNa+ concentration
in plasma
Stimulates
Releases
Osmoreceptorsin hypothalamus
Negativefeedbackinhibits
Posterior pituitary
ADH
Inhibits
Stimulates
Baroreceptorsin atrium andlarge vessels
Stimulates Plasma volumeBP (10–15%)
Antidiuretichormone (ADH)
Targets
Effects
Results in
Collecting ductsof kidneys
OsmolalityPlasma volume
Water reabsorption
Scant urine
996
ADH (Vasopressin)
Vasoconstriction
Water channelsDiabetes Insipidus-Low ADH
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K+ (or Na+) concentrationin blood plasma*
Stimulates
Releases
Targets
Renin-angiotensinmechanism
Negativefeedbackinhibits
Adrenal cortex
Kidney tubules
Aldosterone
Effects
Restores
Homeostatic plasmalevels of Na+ and K+
Na+ reabsorption K+ secretion
Aldosterone
1000
DCT and collecting ducts
Addison’s Disease (low)Aldosteronism (High)
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Intestine
Kidney
Bloodstream
Hypocalcemia (low blood Ca2+) stimulatesparathyroid glands to release PTH.
Rising Ca2+ inblood inhibitsPTH release.
1 PTH activatesosteoclasts: Ca2+
and PO43S released
into blood.
2 PTH increasesCa2+ reabsorptionin kidneytubules.
3 PTH promoteskidney’s activation of vitamin D,which increases Ca2+ absorptionfrom food.
Bone
Ca2+ ions
PTH Molecules
611
Fatty acids
proteins
WBC’s-bilirubin-hepatitis or cirrhosis
CSFHumors
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Feces 4%
Sweat 8%
Insensible lossesvia skin andlungs 28%
Urine 60%
2500 ml
Average outputper day
Average intakeper day
Beverages 60%
Foods 30%
Metabolism 10%
1500 ml
700 ml
200 ml
100 ml
1500 ml
750 ml
250 ml
9942500 ml. 2500 ml.
variable
controlled
Interstitial vs. Intracellular