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LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITIONJane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
© 2011 Pearson Education, Inc.
Lectures by
Erin Barley
Kathleen Fitzpatrick
Osmoregulation and Excretion
Chapter 44
How does an albatross drink salt water without ill effect?
Osmoconformers
vs.
Osmoregulators
What is the difference?
Osmotic Challenges
• Osmoconformers, consisting only of some
marine animals, are isoosmotic with their
surroundings and do not regulate their
osmolarity
• Osmoregulators expend energy to control
water uptake and loss in a hyperosmotic or
hypoosmotic environment (stenohaline and
euryhaline)
© 2011 Pearson Education, Inc.
Do I
drink
water
?
Do I
drink
water
?
Describe
my pee.
Describe my pee.
Figure 44.3
(a) Osmoregulation in a marine fish (b) Osmoregulation in a freshwater fish
Gain of waterand salt ionsfrom food
Excretionof salt ionsfrom gills
Osmotic waterloss through gillsand other partsof body surface
Gain of waterand salt ionsfrom drinkingseawater
Excretion of salt ions andsmall amounts of water inscanty urine from kidneys
Gain of waterand some ionsin food
Uptake ofsalt ionsby gills
Osmotic watergain throughgills and otherparts of bodysurface
Excretion of salt ions andlarge amounts of water indilute urine from kidneys
Key
Water
Salt
Figure 44.4 Sockeye salmon (Oncorhynchus
nerka), euryhaline osmoregulators
Water balance ina kangaroo rat(2 mL/day)
Water balance ina human(2,500 mL/day)
Ingestedin food (0.2)
Ingestedin food (750)
Ingestedin liquid(1,500)Water
gain(mL)
Waterloss(mL)
Derived frommetabolism (1.8)
Derived frommetabolism (250)
Feces (0.09)
Urine(0.45)
Feces (100)
Urine(1,500)
Evaporation (1.46) Evaporation (900)
Figure 44.6
Figure 44.UN01
Animal Inflow/Outflow Urine
Freshwaterfish. Lives inwater lessconcentratedthan body fluids; fishtends to gainwater, lose salt
Does not drink water
Salt in(active trans-port by gills)
H2O in
Salt out
Marine bony fish. Lives inwater moreconcentratedthan bodyfluids; fishtends to losewater, gain salt
Terrestrialvertebrate.Terrestrialenvironment;tends to losebody waterto air
Drinks water
Drinks water
Salt in H2O out
Salt out (activetransport by gills)
Salt in(by mouth)
H2O andsalt out
Large volume of urine
Urine is lessconcentratedthan bodyfluids
Small volumeof urine
Urine isslightly lessconcentratedthan bodyfluids
Moderatevolumeof urine
Urine ismore concentratedthan bodyfluids
Counter-current exchange in salt-excreting nasal glands
What else exhibits c-c e?
Nasal saltgland
Ducts
Nostril with saltsecretions
(a) Location of nasal glandsin a marine bird
(b) Secretorytubules
(c) Countercurrentexchange
Key
Salt movement
Blood flow
Nasal gland
Capillary
Secretory tubule
Transportepithelium
Vein Artery
Central duct
Secretory cellof transportepithelium
Lumen ofsecretorytubule
Saltions
Blood flow Salt secretion
Figure 44.8
Proteins Nucleic acids
Amino
acids
Nitrogenous
bases
—NH2
Amino groups
Most aquatic
animals, including
most bony fishes
Mammals, most
amphibians, sharks,
some bony fishes
Many reptiles
(including birds),
insects, land snails
Ammonia Urea Uric acid
Figure 44.9
Key steps
of
excretory
system
function:
an
overview.
CapillaryFiltration
Excretorytubule
Reabsorption
Secretion
Excretion
Filtra
teU
rine
2
1
3
4
Figure 44.12
Components of a
metanephridium:
Collecting tubule
Internal opening
Bladder
External opening
Coelom Capillary
network
Digestive tract
Midgut
(stomach)Malpighian
tubules
Rectum
IntestineHindgut
Salt, water, and
nitrogenous
wastes
Feces
and urine
Malpighian
tubule
To anus
Rectum
Reabsorption
HEMOLYMPH
Figure 44.13
Figure 44.14-a
Excretory Organs Kidney Structure Nephron Types
Posteriorvena cava
Renalarteryand vein
Aorta
Ureter
Urinarybladder
Urethra
Kidney
Renalcortex
Renalmedulla
Renal artery
Renal vein
Ureter
Cortical nephron
Juxtamedullarynephron
Renal pelvis
Renalcortex
Renalmedulla
Nephron Organization
Afferent arteriolefrom renal artery Glomerulus
Bowman’scapsule
Proximaltubule
Peritubularcapillaries
Distaltubule
Efferentarteriolefrom glomerulus
Collectingduct
Branch ofrenal vein
Vasarecta
Descendinglimb
Ascendinglimb
Loopof
Henle
200
m
Blood vessels from a humankidney. Arterioles and peritubularcapillaries appear pink; glomeruliappear yellow.
Figure 44.14-b
© 2011 Pearson Education, Inc.
Animation: Bowman’s Capsule and Proximal Tubule Right-click slide / select “Play”
Proximal tubule Distal tubule
Filtrate
CORTEX
Loop ofHenle
OUTERMEDULLA
INNERMEDULLA
Key
Active transport
Passive transport
Collectingduct
NutrientsNaCl
NH3
HCO3 H2O K
H
NaCl
H2O
HCO3
K H
H2O
NaCl
NaCl
NaCl H2O
Urea
Figure 44.15
© 2011 Pearson Education, Inc.
Animation: Loop of Henle and Distal TubuleRight-click slide / select “Play”
© 2011 Pearson Education, Inc.
Animation: Collecting DuctRight-click slide / select “Play”
Osmolarityof interstitial
fluid(mOsm/L)
1,200
900
600
400
300
Key
Activetransport
Passivetransport
INNERMEDULLA
OUTERMEDULLA
CORTEXH2O
H2O
H2O
H2O
H2O
H2O
H2O
1,200
900
600
400
300
300
300
Figure 44.16-1
Osmolarityof interstitial
fluid(mOsm/L)
1,200
900
600
400
300
Key
Activetransport
Passivetransport
INNERMEDULLA
OUTERMEDULLA
CORTEXNaClH2O
H2O
H2O
H2O
H2O
H2O
H2O
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
1,200
100
100
200
400
700900
600
400
300
300
300
Figure 44.16-2
Osmolarityof interstitial
fluid(mOsm/L)
Key
Activetransport
Passivetransport
INNERMEDULLA
OUTERMEDULLA
CORTEXNaClH2O
H2O
H2O
H2O
H2O
H2O
H2O
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
NaCl
H2O
H2O
H2O
H2O
H2O
H2O
H2O
Urea
Urea
Urea
1,200
1,2001,200
900
600
400
300300
400
600
100
100
200
400
700900
600
400
300
300
300
Figure 44.16-3
Loops of Henle quiz…
• Who would have longer loops of Henle,
a beaver or a desert hare?
Loops of Henle quiz…
• Who would have longer loops of Henle,
a beaver or a desert hare?
• WHY?
Figure 44.18 A vampire bat (Desmodus rotundas), a
mammal with a unique excretory situation.
Antidiuretic Hormone
• The osmolarity of the urine is regulated by nervous and hormonal control
• Antidiuretic hormone (ADH) makes the collecting duct epithelium more permeable to water– An increase in osmolarity triggers the release of ADH,
which helps to conserve water
© 2011 Pearson Education, Inc.
© 2011 Pearson Education, Inc.
Animation: Effect of ADHRight-click slide / select “Play”
Figure 44.19-1
ThirstHypothalamus
ADH
Pituitarygland
Osmoreceptors inhypothalamus trigger
release of ADH.
STIMULUS:Increase in blood
osmolarity (forinstance, after
sweating profusely)
Homeostasis:Blood osmolarity
(300 mOsm/L)
Figure 44.19-2
ThirstHypothalamus
ADH
Pituitarygland
Osmoreceptors inhypothalamus trigger
release of ADH.
STIMULUS:Increase in blood
osmolarity (forinstance, after
sweating profusely)
Homeostasis:Blood osmolarity
(300 mOsm/L)
Drinking reducesblood osmolarity
to set point.
H2O reab-sorption helpsprevent further
osmolarityincrease.
Increasedpermeability
Distaltubule
Collecting duct
Collectingduct
ADHreceptor
COLLECTINGDUCT CELL
LUMEN
Second-messengersignaling molecule
Storagevesicle
Aquaporinwater channel
Exocytosis
H2O
H2O
ADH
cAMP
Figure 44.20
How might alcohol affect your water
balance?
© 2011 Pearson Education, Inc.
The Renin-Angiotensin-Aldosterone System
• The renin-angiotensin-aldosterone system
(RAAS) is part of a complex feedback circuit
that functions in homeostasis
• A drop in blood pressure near the glomerulus
causes the juxtaglomerular apparatus (JGA)
to release the enzyme renin
• Renin triggers the formation of the peptide
angiotensin II
© 2011 Pearson Education, Inc.
• Angiotensin II
– Raises blood pressure and decreases blood
flow to the kidneys
– Stimulates the release of the hormone
aldosterone, which increases blood volume
and pressure
© 2011 Pearson Education, Inc.
Figure 44.22-1
JGAreleasesrenin.
Renin
Distaltubule
Juxtaglomerularapparatus (JGA)
STIMULUS:Low blood volumeor blood pressure(for example, dueto dehydration or
blood loss)
Homeostasis:Blood pressure,
volume
AngiotensinogenLiver
JGAreleasesrenin.
Renin
Distaltubule
Juxtaglomerularapparatus (JGA)
Angiotensin I
ACE
Angiotensin II
STIMULUS:Low blood volumeor blood pressure(for example, dueto dehydration or
blood loss)
Homeostasis:Blood pressure,
volume
Figure 44.22-2
AngiotensinogenLiver
JGAreleasesrenin.
Renin
Distaltubule
Juxtaglomerularapparatus (JGA)
Angiotensin I
ACE
Angiotensin II
Adrenal gland
Aldosterone
More Na and H2Oare reabsorbed in
distal tubules,increasing blood volume.
Arteriolesconstrict,increasing
blood pressure.
STIMULUS:Low blood volumeor blood pressure(for example, dueto dehydration or
blood loss)
Homeostasis:Blood pressure,
volume
Figure 44.22-3
Homeostatic Regulation of the Kidney
• ADH and RAAS both increase water
reabsorption, but only RAAS will respond to a
decrease in blood volume
• Another hormone, atrial natriuretic peptide
(ANP), opposes the RAAS
• ANP is released in response to an increase in
blood volume and pressure and inhibits the
release of renin
© 2011 Pearson Education, Inc.
Check out Bioflix,
and Bozeman “Osmoregulation”
Test Your Understanding question 7