Urinary System Review Questions: 1. This system would be lined with what type of membrane? 2. What...

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


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


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)


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


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


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


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


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


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.


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.)


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


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


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.


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

© 2013 Pearson Education, Inc.

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


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


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


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)


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


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


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


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


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)


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


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

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