Transcript a feather and fur

Homeostasis
• Maintain a “steady state” or internal balance
regardless of external environment
• Fluctuations above/below a set point serve as a
stimulus; these are detected by a sensor
(receptor), sends a signal and triggers a
response
• The response returns the variable to the set point
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Negative Feedback
• “More gets you less.”
• Return changing
conditions back to set
point
• Examples:
– Temperature
– Blood glucose levels
– Blood pH
Plants: response to water
limitations
Positive Feedback
• “More gets you more.”
• Response moves variable
further away from set point
• Stimulus amplifies a
response
• Examples:
– Lactation in mammals
– Onset of labor in childbirth
Plants: ripening of fruit
Positive or Negative Feedback?
• Cyclin protein is produced at the beginning of the
G2 phase. Cyclin production continues to increase
as the cell moves through the G2 phase. Cyclin
production reaches is maximum just before the
start of the M phase.
4
Positive or Negative Feedback?
• When ATP levels are high in a cell,
enzymes involved in glycolysis are
allosterically inhibited. This results in a
reduction in the amount of ATP produced.
5
Do Now:
• Animals get energy from FOOD
• Digestion provides monomers required
for…
• ATP synthesis, cellular work, and
biosynthesis (growth, repair,
reproduction)
6
What is thermoregulation?
• Maintaining of internal temperatures in
an organism
• endotherms and ectotherms
7
Are these endotherms or ectotherms?
• ENDOTHERMS
8
Characteristics of Endotherms:
• Maintain constant internal body temp
Generate heat from metabolism (C.R.)
• Requires more energy
• Higher Metabolic Rates
– Highest in very COLD temps (why?)
– Negative feedback mechanism!
• Birds and Mammals
9
Characteristics of Ectotherms
• Internal temp changes with the
environmental temp
• Get heat from external sources
• Lower metabolic rates
• Less food intake
• Behavioral adaptations
Play an impt role
• All other animals
10
Figure 40.10
How does this graph characterize the relationship
between environmental temperature and body
temperature of endotherms and ectotherms?
An organisms metabolic rate is the
sum of all energy requiring chemical
reactions. How can scientists measure
the metabolic rate of organisms?
•
•
•
•
Cell Respiration Rates!
Oxygen consumption
CO2 production
Heat Loss
12
Comparing the energy expenditures in various sized
endotherms and ectotherms
• Observations:
13
How does the size of an organism affect is metabolic
rate? (Comparison of various mammals ENDOTHERMS)
• Observations and Predictions
14
Five adaptations for thermoregulation:
•
•
•
•
•
Insulation (skin, feather, fur, blubber)
Circulatory adaptations (countercurrent exchange)
Cooling by evaporative heat loss (sweat)
Behavioral responses (shivering, shade, basking)
Adjusting metabolic heat production
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25.3 Thermoregulation involves adaptations
that balance heat gain and loss
1. Insulation is provided by
– hair,
– feathers, and
– fat layers.
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25.3 Thermoregulation involves adaptations
that balance heat gain and loss
2. Circulatory
adaptations include
– increased or decreased
blood flow to skin and
– Heat moves from high
to low temps between
arteries and veins
(countercurrent).
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25.3 Thermoregulation involves adaptations
that balance heat gain and loss
3. Evaporative cooling may involve
– sweating,
– panting, or
– spreading saliva on body surfaces.
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Figure 25.3_1
Heat dissipation
(Via ear flapping)
Evaporative
Cooling
25.3 Thermoregulation involves adaptations
that balance heat gain and loss
4. Behavioral responses
– are used by endotherms and ectotherms and
– include
» moving to the sun (basking) or shade,
» migrating, and
» bathing.
Color changes
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25.3 Thermoregulation involves adaptations
that balance heat gain and loss
• 5. Increased metabolic heat production
occurs when
–
–
–
–
Increased cell respiration,
birds and mammals shiver,
organisms increase their physical activity, and
honeybees cluster and shiver.
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Figure 25.3_UN01
What are these organisms doing???
Torpor and Energy Conservation
• Torpor is a physiological state in which activity is
low and metabolism decreases
• Save energy while avoiding difficult and
dangerous conditions
• Hibernation: torpor during winter
• Estivation: summer torpor
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Figure 25.3_UN01
25.3 Thermoregulation involves adaptations
that balance heat gain and loss
• Circulatory adaptations include
– increased or decreased blood flow to skin and
– countercurrent heat exchange, with warm
and cold blood flowing in opposite directions.
© 2012 Pearson Education, Inc.
Figure 25.3_1
Ear flapping to release excess heat; water spray for evaporative cooling
Figure 25.3_2
Blood from
body core
in artery
Blood
returning to
body core
in vein
35
33C
30
27
20
18
10
9
Blood from
body core
in artery
Blood
returning
to body
core in vein
Figure 40.12
What is countercurrent heat exchange?
Animation
What is countercurrent heat
exchange?
• Prevents the loss
Of a large amount of
Heat by transferring
Heat from warm
Blood to cooler
Adjacent blood
Animation
30
Which body systems are involved in
mammalian thermoregulation?
• Integumentary (skin)
• Muscular
• Circulatory
31
Figure 40.16
When body
temperature
decreases:
Shivering and
Constriction of Blood
Vessels
When body
temperature
increases: Sweating
and dilation of blood
vessels
OSMOREGULATION
AND EXCRETION
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25.4 Animals balance the level of water and
solutes through osmoregulation
 Osmoregulation is the homeostatic control of the
uptake and loss of water and solutes such as salt
and other ions.
 Osmosis is one process whereby animals regulate
their uptake and loss of fluids.
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25.4 Animals balance the level of water and
solutes through osmoregulation
• Osmoconformers
– have body fluids with a solute concentration
equal to that of seawater,
– face no substantial challenges in water balance,
and
– include many marine invertebrates.
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25.4 Animals balance the level of water and
solutes through osmoregulation
 Osmoregulators
• have body fluids whose solute concentrations differ from
that of their environment,
• must actively regulate water movement, and
• include
– many land animals,
– freshwater animals such as trout, and
– marine vertebrates such as sharks.
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25.4 Animals balance the level of water and
solutes through osmoregulation
 Freshwater fish
•
•
•
•
gain water by osmosis (mainly through gills),
lose salt by diffusion to the more dilute environment,
take in salt through their gills and in food, and
excrete excess water in dilute urine.
© 2012 Pearson Education, Inc.
Figure 25.4_1
Uptake of
some ions
in food
Osmotic water gain through gills
and other parts of body surface
Uptake
of salt ions
by gills
Fresh water
Excretion of large
amounts of water
in dilute urine
from kidneys
25.4 Animals balance the level of water and
solutes through osmoregulation
• Saltwater fish
– lose water by osmosis from the gills and body
surface,
– drink seawater, and
– use their gills and kidneys to excrete excess
salt.
© 2012 Pearson Education, Inc.
Figure 25.4_2
Gain of water and
salt ions from food
and by intake of
seawater
Osmotic water loss through gills
and other parts of body surface
Excretion of
salt from gills
Salt water
Excretion of excess ions
and small amounts of
water in concentrated
urine from kidneys
25.4 Animals balance the level of water and
solutes through osmoregulation
• Land animals
–
–
–
–
face the risk of dehydration,
lose water by evaporation and waste disposal,
gain water by drinking and eating, and
conserve water by
•
•
•
•
reproductive adaptations,
behavior adaptations,
waterproof skin, and
efficient kidneys.
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25.5 EVOLUTION CONNECTION: A variety
of ways to dispose of nitrogenous wastes
has evolved in animals
• Metabolism produces toxic by-products.
• Nitrogenous wastes are toxic breakdown
products of proteins and nucleic acids.
• Animals dispose of nitrogenous wastes in
different ways.
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25.5 EVOLUTION CONNECTION: A variety
of ways to dispose of nitrogenous wastes
has evolved in animals
• Ammonia (NH3) is
–
–
–
–
poisonous,
too toxic to be stored in the body,
soluble in water, and
easily disposed of by aquatic animals.
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25.5 EVOLUTION CONNECTION: A variety
of ways to dispose of nitrogenous wastes
has evolved in animals
• Urea is
– produced in the vertebrate liver by combining
ammonia and carbon dioxide,
– less toxic,
– easier to store, and
– highly soluble in water.
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25.5 EVOLUTION CONNECTION: A variety
of ways to dispose of nitrogenous wastes
has evolved in animals
• Uric acid is
– excreted by some land animals (insects, land
snails, and many reptiles),
– relatively nontoxic,
– largely insoluble in water,
– excreted as a semisolid paste, conserving
water, but
– more energy expensive to produce.
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Figure 25.5
Proteins
Amino acids
Nitrogenous bases
Nucleic acids
NH2
(amino groups)
Most aquatic animals,
including most bony
fishes
Mammals, most
amphibians, sharks,
some bony fishes
Birds and many other
reptiles, insects, land
snails
Uric acid
Ammonia
Urea
25.6 The urinary system plays several major
roles in homeostasis
• The urinary system
– forms and excretes urine and
– regulates water and solutes in body fluids.
• In humans, the kidneys are the main
processing centers of the urinary system.
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25.6 The urinary system plays several major
roles in homeostasis
• Nephrons
– are the functional units of the kidneys,
– extract a fluid filtrate from the blood, and
– refine the filtrate to produce urine.
• Urine is
– drained from the kidneys by ureters,
– stored in the urinary bladder, and
– expelled through the urethra.
Animation: Nephron Introduction
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Figure 25.6
Renal cortex
Renal medulla
Aorta
Inferior
vena cava
Renal artery (red)
and vein (blue)
Ureter
Kidney
Renal pelvis
Urinary bladder
Urethra
The urinary system
Bowman’s
capsule
Glomerulus
Arteriole
from renal
artery
1
Ureter
Proximal tubule
Capillaries
3
Arteriole
from
glomerulus
Distal
tubule
Collecting
duct
From
another
nephron
Branch of
renal vein
The kidney
Bowman’s
capsule
Tubule
Renal cortex
Branch of
renal artery
Branch of
renal vein
Collecting
duct
Renal medulla
2
Loop of Henle
with capillary
network
Detailed structure of a nephron
To
renal
pelvis
Orientation of a nephron within the kidney
Figure 25.6_1
Aorta
Inferior
vena cava
Renal artery (red)
and vein (blue)
Ureter
Urinary bladder
Urethra
The urinary system
Kidney
Figure 25.6_2
Renal cortex
Renal medulla
Renal pelvis
Ureter
The kidney
Figure 25.6_3
Bowman’s
capsule
Tubule
Renal cortex
Branch of
renal artery
Branch of
renal vein
Collecting
duct
Renal medulla
To
renal
pelvis
Orientation of a nephron within the kidney
Figure 25.6_4
Arteriole
from renal
artery
Bowman’s
capsule
Glomerulus
1
Proximal tubule
Capillaries
3
Arteriole
from
glomerulus
From
another
nephron
Branch of
renal vein
2
Distal
tubule
Collecting
Duct
Loop of Henle
with capillary
network
Detailed structure of a nephron
25.7 Overview: The key processes of the urinary
system are filtration, reabsorption,
secretion, and excretion
• Filtration
– Blood pressure forces water and many small
molecules through a capillary wall into the start
of the kidney tubule.
• Reabsorption
– refines the filtrate,
– reclaims valuable solutes (such as glucose,
salt, and amino acids) from the filtrate, and
– returns these to the blood.
© 2012 Pearson Education, Inc.
Figure 25.7
Bowman’s
From
capsule
renal
artery
Filtration
Reabsorption
Secretion
Excretion
Nephron tubule
H2O, other small molecules
Urine
Interstitial fluid
Capillary
To renal vein
Figure 25.7_1
From Bowman’s
renal capsule
artery
Filtration
Nephron tubule
H2O, other small molecules
Interstitial fluid
Capillary
Figure 25.7_2
Reabsorption
Secretion
Excretion
Nephron tubule
Urine
Capillary
To renal vein
25.7 Overview: The key processes of the urinary
system are filtration, reabsorption,
secretion, and excretion
• Substances in the blood are transported into
the filtrate by the process of secretion.
• By excretion the final product, urine, is
excreted via the ureters, urinary bladder, and
urethra.
© 2012 Pearson Education, Inc.
Figure 25.7
Bowman’s
From
capsule
renal
artery
Filtration
Reabsorption
Secretion
Excretion
Nephron tubule
H2O, other small molecules
Urine
Interstitial fluid
Capillary
To renal vein
25.8 Blood filtrate is refined to urine through
reabsorption and secretion
• Reabsorption in the proximal and distal
tubules removes
– nutrients,
– salt, and
– water.
• pH is regulated by
– reabsorption of HCO3– and
– secretion of H+.
© 2012 Pearson Education, Inc.
25.8 Blood filtrate is refined to urine through
reabsorption and secretion
• High NaCl concentration in the medulla
promotes reabsorption of water.
Animation: Bowman’s Capsule and Proximal Tubule
Animation: Collecting Duct
Animation: Effect of ADH
Animation: Loop of Henle and Distal Tubule
© 2012 Pearson Education, Inc.
Figure 25.8
Bowman’s
capsule
Proximal tubule
Nutrients H2O

NaCl HCO3
1
Distal tubule
H2O
NaCl
HCO3
Blood
Cortex
Filtrate composition
H2O
Salts (NaCl and others)
HCO3
H
Urea
Glucose
Amino acids
Some drugs
K
Some H
drugs
and poisons
H
3
Collecting
duct
Medulla
Interstitial
Loop of
fluid
Henle
2
NaCl
NaCl
H2O
NaCl
Urea
H2O
Reabsorption
Secretion
Filtrate movement
Urine (to
renal pelvis)
Figure 25.8_1
Bowman’s
capsule
Proximal tubule
Nutrients H2O

NaCl HCO3
Blood
Cortex
Filtrate composition
H2O
Salts (NaCl
and others)
HCO3
H
Urea
Glucose
Amino acids
Some drugs
Some H
drugs
and poisons
Medulla
Reabsorption
Secretion
Filtrate movement
Figure 25.8_2
Proximal tubule
Nutrients H2O

NaCl HCO3
Cortex
1
Some H
drugs
and poisons
Distal tubule
H2O
NaCl HCO3
K H
3
Collecting
duct
Medulla
Interstitial
Loop of
fluid
Henle
2
NaCl
NaCl
H2O
NaCl
Urea
H2O
Reabsorption
Secretion
Filtrate
movement
Urine (to
renal pelvis)
25.9 Hormones regulate the urinary system
• Antidiuretic hormone (ADH) regulates the
amount of water excreted by the kidneys by
– signaling nephrons to reabsorb water from the
filtrate, returning it to the blood, and
– decreasing the amount of water excreted.
• Diuretics
– inhibit the release of ADH and
– include alcohol and caffeine.
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25.10 CONNECTION: Kidney dialysis can be
lifesaving
• Kidney failure can result from
– hypertension,
– diabetes, and
– prolonged use of common drugs, including
alcohol.
• A dialysis machine
– removes wastes from the blood and
– maintains its solute concentration.
© 2012 Pearson Education, Inc.
Figure 25.9
Line from artery to apparatus
Pump
Line from
apparatus
to vein
Tubing made of a
selectively permeable
membrane
Dialyzing
solution
Fresh dialyzing
solution
Used dialyzing solution
(with urea and excess ions)
Figure 25.9_1
Line from artery to apparatus
Pump
Line from
apparatus
to vein
Tubing made of a
selectively permeable
membrane
Dialyzing
solution
Fresh dialyzing
solution
Used dialyzing solution
(with urea and excess ions)
Figure 25.9_2
You should now be able to
1. Explain how bear physiology adjusts during
dormancy.
2. Describe four ways that heat is gained or
lost by an animal.
3. Describe five categories of adaptations that
help animals thermoregulate.
4. Compare the osmoregulatory problems of
freshwater fish, saltwater fish, and terrestrial
animals.
© 2012 Pearson Education, Inc.
You should now be able to
5. Compare the three ways that animals
eliminate nitrogenous wastes.
6. Describe the structure and functions of the
human kidney.
7. Explain how the kidney promotes
homeostasis.
8. Describe four major processes that produce
urine.
9. Describe the key events in the conversion of
filtrate into urine.
© 2012 Pearson Education, Inc.
Figure 25.4_UN01
Figure 25.UN01
35
33C
30
27
20
18
10
9
Figure 25.UN02
Gain Water
Lose Water
Salt
Osmosis
Excretion
Pump in
Saltwater Fish
Drinking
Osmosis
Excrete,
pump out
Land Animal
Drinking,
eating
Evaporation,
urinary system
Freshwater
Fish
Figure 25.UN03
Urea
Figure 25.UN04
Kidney
Ureter
Bladder
Figure 25.UN05
Homeostasis
involves processes of
(b)
(a)
maintains
animal may balance of
be
(c)
both done by
water and
solutes
human
kidney
requirements
depend on
(d)
involves
removal of
nitrogenous
wastes
form may be
(e)
mechanisms
mostly
endotherm
mechanisms
include
(f)
(g)
depends on
(h)
(i)
may be
heat
production, insulation,
countercurrent
heat exchange
ocean, fresh
water,
land
reproduction
(where embryo
develops)
Figure 25.UN06
(a)
(b)
(c)
Bowman’s
capsule
From renal
artery
To renal
vein
Glomerulus
Tubule
Loop
of Henle Capillaries
Collecting
duct
(d)