Download Osmoregulation and Excretion

Fig. 44-1
Chapter 44
How does an albatross drink
saltwater without ill effect?
Osmoregulation and
Excretion
PowerPoint® Lecture Presentations for
Biology
Osmoregulation
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Osmosis and Osmolarity
Fig. 44-2
Selectively permeable
membrane
• Cells require a balance between osmotic gain
and loss of water
• Osmolarity, the solute concentration of a
solution, determines the movement of water
across a selectively permeable membrane
Solutes
Net water flow
Water
• If two solutions are isoosmotic, the movement
of water is equal in both directions
• If two solutions differ in osmolarity, the net flow
of water is from the hypoosmotic to the
hyperosmotic solution
Hyperosmotic side
Hypoosmotic side
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings
Osmotic Challenges
• Osmoconformers, consisting only of some
marine animals, are isoosmotic with their
surroundings and do not regulate their
osmolarity
• Osmoconformers (滲透壓耐受者)
• O
Osmoregulators expend energy to control
water uptake and loss in a hyperosmotic or
hypoosmotic environment
• Stenohaline (狹滲透壓)
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings
• Osmoregulators (滲透壓調節者)
• Euryhaline (廣滲透壓)
Copyright © 2008 Pearson Education Inc., publishing as Pearson Benjamin Cummings
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Fig. 44-3
Fig. 44-4a
Gain of water and
salt ions from food
Euryhaline osmoregulator
Gain of water
and salt ions from
drinking seawater
Osmotic water
Excretion
of salt ions loss through gills
and other parts
from gills
of body surface
Excretion of salt ions and
small amounts of water in
scanty urine from kidneys
(a) Osmoregulation in a saltwater fish
Fig. 44-4b
Uptake of water and
some ions in food
Osmotic water
Uptake
of salt ions gain through gills
and other parts
by gills
of body surface
Fig. 44-5
Anhydrobiosis (耐脫水)
100 µm
100 µm
Excretion of large
amounts of water in
dilute urine from kidneys
(a) Hydrated tardigrade
(b) Dehydrated
tardigrade
(b) Osmoregulation in a freshwater fish
Fig. 44-6
Fig. 44-7
Water
balance in a
kangaroo rat
(2 mL/day)
Ingested
in food (0.2)
Water
gain
(mL)
Water
balance in
a human
(2,500 mL/day)
Ingested
in food (750)
Ingested
in liquid
(1,500)
D i d from
Derived
f
metabolism (250)
D i d from
Derived
f
metabolism (1.8)
Feces (0.09)
Water
loss
(mL)
Urine
(0.45)
Evaporation (1.46)
EXPERIMENT
Ducts
Nasal salt
gland
Nostril
with salt
secretions
Feces (100)
Urine
(1,500)
Evaporation (900)
2
Fig. 44-9
Proteins
Nucleic acids
Amino
acids
Nitrogenous
bases
Fig. 44-14
Renal
medulla
Posterior
vena cava
Renal artery
and vein
Aorta
Amino groups
Renal
cortex
Kidney
Renal
pelvis
Ureter
Urinary
bladder
Urethra
Ureter
(a) Excretory organs and major
associated blood vessels
Juxtamedullary
nephron
Section of kidney
from a rat
(b) Kidney structure
Cortical
nephron
4 mm
Afferent arteriole Glomerulus
from renal artery
Bowman’s capsule
SEM
Proximal tubule
10 µm
Peritubular capillaries
Most aquatic
animals, including
most bony fishes
Many reptiles
Mammals, most
amphibians, sharks, (including birds),
insects, land snails
some bony fishes
Renal
cortex
Efferent
arteriole from
glomerulus
Collecting
duct
Loop of
Henle
(c) Nephron types
Urea
Uric acid
Filtration of the Blood
Vasa
recta
Fig. 44-UN1
Animal
• Filtration occurs as blood pressure forces fluid
from the blood in the glomerulus into the lumen
of Bowman’s capsule
• The filtrate contains salts, glucose, amino acids,
vitamins, nitrogenous wastes, and other small
molecules
Ascending
limb
(d) Filtrate and blood flow
Freshwater
fish
• Filtration of small molecules is nonselective
Collecting
duct
Descending
limb
To
renal
pelvis
Ammonia
Distal
tubule
Branch of
renal vein
Renal
medulla
Inflow/Outflow
Does not drink water
Salt in
H2O in
(active transport by gills)
Urine
Large volume
of urine
Urine is less
concentrated
than body
fluids
Salt out
Bony marine
fish
Drinks water
Salt in H2O out
Small volume
of urine
Urine is
li h l less
l
slightly
concentrated
than body
fluids
Salt out (active
transport by gills)
Terrestrial
vertebrate
Drinks water
Salt in
(by mouth)
H2O and
salt out
Moderate
volume
of urine
Urine is
more
concentrated
than body
fluids
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