Transcript Chapter 29 Opener Figure 29.1 The Internal Environment Figure 29.1 The Internal Environment.

Chapter 29 Opener
Figure 29.1 The Internal Environment
Figure 29.1 The Internal Environment
Apply the Concept, Ch. 29, p. 589
Figure 29.2 Tissues Form Organs
Figure 29.2 Tissues Form Organs
Concept 29.1 Multicellular Animals Require a Stable Internal Environment
Working in pairs and without looking at your notes, define
“homeostasis” to the other person in your own words.
Then ask your partner if he/she has any changes or
additions to your definition.
Now consider the following scenario: An adult bird and a
newly hatched nestling are exposed to unusually cold
conditions during a late spring blizzard. The adult bird
maintains a constant internal temperature. However, the
nestling’s body temperature begins to drop.
Are both these birds achieving homeostasis? Why or why
not?
Concept 29.1 Multicellular Animals Require a Stable Internal Environment
Which bird is achieving homeostasis?
a. The adult
b. The nestling
c. Both
d. Neither
e. I don’t know
Concept 29.1 Multicellular Animals Require a Stable Internal Environment
Discuss why the adult’s body temperature stayed steady
while the nestling's temperature fell. That is, develop
some hypotheses about what exactly the adult bird might
have been doing differently than the nestling. Try to think
of at least three different hypotheses.
How could you test your ideas?
Working in small groups, outline a simple experiment to
test one of your hypotheses. In the first sentence, state
your hypothesis; then describe your experiment very
briefly in 2–3 additional sentences.
Concept 29.1 Multicellular Animals Require a Stable Internal Environment
Working in pairs and without looking at your notes, one
person (A) name a type of tissue. The other person (B)
then list the tissue's characteristics, and give at least one
specific example. Once person B has run out of ideas,
person A can list more tissue characteristics and
examples. (If you wish, you can keep score; who can list
more tissue characteristics and examples?)
Then switch roles and continue.
At the end, check your notes to see if your statements were
correct. (Tally up your scores: who won?)
Figure 29.3 Control, Regulation, and Feedback
Figure 29.3 Control, Regulation, and Feedback
Concept 29.2 Physiological Regulation Achieves Homeostasis of the Internal Environment
During labor, the pressure of the fetus’s head on the cervix
causes release of the hormone oxytocin from the
mother’s posterior pituitary gland. Oxytocin stimulates
contractions of the uterus, which increases the pressure
on the cervix, which causes release of even more
oxytocin.
Is this an example of negative feedback, positive feedback,
or feedforward information? Why? Does it ever reach a
limit?
Discuss with a friend.
Concept 29.2 Physiological Regulation Achieves Homeostasis of the Internal Environment
Are labor contractions an example of negative feedback,
positive feedback, or feedforward?
a. Negative feedback
b. Positive feedback
c. Feedforward
d. None of the above
e. I don’t know.
Concept 29.2 Physiological Regulation Achieves Homeostasis of the Internal Environment
Respiration minute volume is usually regulated by feedback
systems that monitor the O2 and CO2 content of the
blood. If O2 or CO2 levels deviate from normal, minute
volume changes rapidly to return the O2 or CO2 levels to
normal. Usually, minute volume does not change until O2
or CO2 have deviated from normal.
However, an interesting phenomenon occurs when people
run. When a person starts running, minute volume
suddenly increases dramatically during the first few
running steps, even though O2 and CO2 levels have not
yet changed.
Is this an example of negative feedback, positive feedback,
or feedforward? Why? Discuss with a friend.
Concept 29.2 Physiological Regulation Achieves Homeostasis of the Internal Environment
The increase in minute volume that occurs during the first
steps of running, before O2 or CO2 levels change, is most
likely an example of
a. positive feedback.
b. negative feedback.
c. feedforward.
d. None of the above
e. I don’t know.
Figure 29.4 Q10 and Reaction Rate
Figure 29.4 Q10 and Reaction Rate
Figure 29.5 Ectotherms and Endotherms React Differently to Environmental Temperatures
Figure 29.5 Ectotherms and Endotherms React Differently to Environmental Temperatures
Figure 29.5 Ectotherms and Endotherms React Differently to Environmental Temperatures (Part 1)
Figure 29.5 Ectotherms and Endotherms React Differently to Environmental Temperatures (Part 2)
In-Text Art, Ch. 29, p. 594
Apply the concept p. 594
Living systems are temperature-sensitive
Neurons convey information from one part of the body to another
as streams of electrical signals called nerve impulses.
Information is coded as the frequency of nerve impulses
(impulses/sec). Thus, changes in temperature of neurons can
alter the information they are transmitting. A neurobiologist
recorded the impulse frequencies of three different types of
neurons in the skin of an animal at different skin
temperatures.
1. Calculate the Q10 for each of the three neuron types.
2. On the basis of your calculations, what type of information do
you think each different neuron might be conveying from the
skin to the brain?
Apply the Concept, Ch. 29, p. 594
1. Calculate the Q10 for each of the three neuron types.
2. On the basis of your calculations, what type of information
do you think each different neuron might be conveying from
the skin to the brain?
Concept 29.3 Living Systems Are Temperature-Sensitive
Suppose that you are studying a tame, winter-acclimatized Arctic fox. You
follow your fox around during a winter in northern Alaska, measuring its
oxygen consumption and body temperature periodically. You discover:
• At environmental temperatures between –7°C and approximately
+20°C, your fox maintains a normal body temperature without any
change in metabolic rate.
• Above +20°C, the fox’s metabolic rate begins to rise, and it starts
panting.
• As temperatures drop lower than –7°C, the fox’s metabolic rate begins
to rise, and it begins shivering slightly. It maintains a normal body
temperature.
• At temperatures below –40°C, the fox’s metabolic rate rises quite high
and it shivers very strongly, but it still maintains a normal body
temperature. At these temperatures the fox spends most of its time in its
den, curled into a round ball, with its nose and feet tucked into its fur.
• One night the environmental temperature drops to a record low below –
80°C, and the fox’s body temperature begins to drop for the first time.
(At this point you bring the fox into your house by the fireplace, and
cease the experiment.)
Discuss, in pairs or small groups:
What is your Arctic fox’s thermoneutral zone, and its lower critical
temperature?
Concept 29.3 Living Systems Are Temperature-Sensitive
What is your Arctic fox’s thermoneutral zone?
a. This animal is an ectotherm, and thus has no
thermoneutral zone.
b. This animal is an endotherm, and thus has no
thermoneutral zone.
c. From –40°C to –7°C
d. From –7°C to +20°C
e. From –80°C to +20°C
Concept 29.3 Living Systems Are Temperature-Sensitive
What is this Arctic fox’s lower critical temperature?
a. +20°C
b. –7°C
c. –40°C
d. –80°C
e. The lower critical temperature was not determined,
since the fox survived all the temperatures that it was
exposed to.
Concept 29.3 Living Systems Are Temperature-Sensitive
Which of the following thermoregulatory responses did the
Arctic fox show at temperatures below –40°C?
a. Shivering
b. Torpor
c. Behavioral thermoregulation
d. Both a and c
e. All of the above
Concept 29.3 Living Systems Are Temperature-Sensitive
Working in pairs, draw a graph that illustrates how the
Arctic fox’s MR (on the y-axis) changes with temperature
(x-axis).
Label the thermoneutral zone, the lower critical
temperature, and the upper critical temperature.
Now add a new line to the graph illustrating your prediction
about what you think might happen if you tested this
same fox when it had a summer coat and was
acclimatized to summer temperatures.
Compare your graphs with those of your classmates, and
discuss.
Figure 29.6 Animals Exchange Heat with the Environment
Figure 29.6 Animals Exchange Heat with the Environment
Figure 29.7 Brown Fat
Figure 29.7 Brown Fat
Figure 29.8 The Mouse-to-Elephant Curve
Figure 29.9 Anatomical Adaptations to Climate
Figure 29.9 Anatomical Adaptations to Climate (Part 1)
Figure 29.9 Anatomical Adaptations to Climate (Part 2)
Figure 29.10 “Cold” and “Hot” Fish
Figure 29.10 “Cold” and “Hot” Fish
Figure 29.10 “Cold” and “Hot” Fish (Part 1)
Figure 29.10 “Cold” and “Hot” Fish (Part 2)
Figure 29.10 “Cold” and “Hot” Fish (Part 3)
Figure 29.11 Bees Keep Warm in Winter
Figure 29.12 Ectotherms Can Use Behavior to Regulate Body Temperature
Figure 29.12 Ectotherms Can Use Behavior to Regulate Body Temperature
Figure 29.12 Ectotherms Can Use Behavior to Regulate Body Temperature (Part 1)
Figure 29.12 Ectotherms Can Use Behavior to Regulate Body Temperature (Part 2)
Figure 29.13 The Hypothalmus Regulates Body Temperature
Figure 29.13 The Hypothalmus Regulates Body Temperature
Figure 29.13 The Hypothalmus Regulates Body Temperature (Part 1)
Figure 29.13 The Hypothalmus Regulates Body Temperature (Part 2)
Figure 29.14 Hibernation Patterns in a Ground Squirrel
Figure 29.14 Hibernation Patterns in a Ground Squirrel
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
You are (presumably) maintaining a stable body temperature right now.
How is this being accomplished?
Working in small groups, briefly list all of the sources of heat gain and
heat loss that are affecting you right now, and state which of the
following categories they fall into:
• Metabolism
• Radiation
• Convection
• Conduction
• Evaporation
Note that answers may differ for different people in the group,
depending on where exactly you are sitting, what you are wearing,
and what you have been doing recently.
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
Discuss with a partner whether the following situations will cause heat
gain or heat loss, and identify how the heat is being generated or
transferred (metabolism, radiation, conduction, convection, or
evaporation):
1. Sitting on a very cold seat at a football stadium
2. Sitting in a hot tub, with warm water flowing around you.
(Assume the water is warmer than your skin.)
3. Sunbathing, with most of your body exposed to strong direct
sunlight
4. Jogging in place while waiting at a chilly bus stop
5. Sweating on a hot day. (The sweat evaporates.)
6. Standing in front of a fan that is blowing cool air at you. (Assume
the air is cooler than your skin.)
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
sitting on a very cold seat at a football stadium?
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
sitting in a hot bathtub, in still water?
[Assume the water is warmer than your skin.]
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
sunbathing?
[Most of your body is exposed to strong direct sunlight.]
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
jogging in place while waiting at a chilly bus stop?
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
sweating on a hot day?
[The sweat evaporates.]
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.4 Animals Control Body Temperature by Altering Rates of Heat Gain And Loss
What is the cause of heat gain or heat loss when you are:
standing in front of a fan that is blowing cool air at you?
[Assume the air is cooler than your skin.]
a. Metabolism
b. Radiation
c. Convection
d. Conduction
e. Evaporation
Concept 29.5 A Thermostat in the Brain Regulates Mammalian Body Temperature
A fever often begins with “the chills,” meaning that the person feels
chilly and may even start shivering, despite the fact that body
temperature is actually increasing above normal.
Later, when the disease has run its course, the fever “breaks” and the
person often suddenly begins sweating profusely. Body temperature
then declines toward normal.
Discuss with a partner or in small groups:
• Why does a person with a fever start shivering, even though
body temperature is normal or above normal?
• Later, why does sweating suddenly begin when the fever breaks?
(That is, what has triggered the sweating, and why wasn’t the
person already sweating before that?)
Concept 29.5 A Thermostat in the Brain Regulates Mammalian Body Temperature
What is the most probable cause of “the chills” at the beginning of an
illness, and the sweating that occurs when a fever “breaks”?
a. During a fever, the hypothalamus becomes warmer than the rest
of the body.
b. During a fever, the hypothalamus becomes cooler than the rest
of the body.
c. The hypothalamus raises its set point at the beginning of a fever,
and lowers it when the fever breaks.
d. The hypothalamus lowers its set point at the beginning of a
fever, and raises it when the fever breaks.
e. These are most likely random responses, because body
temperature is not regulated during a fever.
Concept 5.3 Some Substances Require Energy to Cross the Membrane
Consider the following statements, and discuss whether
each is correct:
• Simple or facilitated diffusion requires cellular energy.
• Diffusion results in a net flow of solute down a
concentration gradient, while active transport works
against the concentration gradient.
• Secondary active transport uses energy to set up a
concentration gradient which then allows some
passive diffusion to occur, which recaptures some of
the energy expended.
• Membrane proteins are required for all membrane
transport into and out of cells.
Figure 5.3 Osmosis Can Modify the Shapes of Cells
Concept 5.2 Some Substances Can Cross the Membrane by Diffusion, Part 1
Discuss the following scenarios with a partner or with a
group:
• A cucumber placed in a solution of brine (very salty
water), over time turning into a pickle
• A person sitting in a tapwater bath
Osmosis of water by diffusion is the only process occurring
in these two scenarios.
Discuss the direction of the gradient of water flow, and
determine the correct term (e.g., isotonic, hypertonic,
etc.) for the starting condition inside of the cells (plant
cells of the cucumber, and skin cells of the human in the
bath).
Concept 5.2 Some Substances Can Cross the Membrane by Diffusion, Part 1
Consider the process of osmosis for:
• A cucumber placed in a solution of brine (very salty
water), over time turning into a pickle
• A person sitting in a tapwater bath
Which of the following correctly describes the scenarios at
the starting condition?
a. The cucumber is hypotonic with respect to the brine.
b. The human skin cells are hypertonic with respect to
the bathwater.
c. Water begins to flow by osmosis into the cucumber
and out of the human skin cells.
d. Both a and b
e. All of the above
Figure 5.3 Osmosis Can Modify the Shapes of Cells
Figure 5.3 Osmosis Can Modify the Shapes of Cells (Part 1)
Figure 5.3 Osmosis Can Modify the Shapes of Cells (Part 2)
Figure 5.3 Osmosis Can Modify the Shapes of Cells (Part 3)
Concept 5.2 Some Substances Can Cross the Membrane by Diffusion, Part 2
Type 2 diabetes, often associated with obesity, results in
an increase in blood-glucose levels. It occurs in humans
as well as in animals, including domestic dogs and cats.
One early sign that a person or animal might be developing
type 2 diabetes is excessive thirst. Discuss a possible
reason for this symptom based on what you have learned
in this chapter about tonicity in cells.
Concept 5.2 Some Substances Can Cross the Membrane by Diffusion, Part 2
Type 2 diabetes, often associated with obesity, results in
an increase in blood-glucose levels. It occurs in humans
as well as in animals, including domestic dogs and cats.
One early sign that a person or animal might be developing
type 2 diabetes is excessive thirst. Consider the following
possible explanation:
Elevated glucose levels in blood would result in water
leaving cells, causing dehydration.
a. True
b. False
c. I don’t know.
Figure 40.1 Osmoconformity Has Limits
Concept 40.1 Excretory Systems Maintain Homeostasis of the Extracellular Fluid
The sea, the land, and freshwater
Consider the groups of animals listed below:
• Freshwater animals
• Terrestrial animals
• Marine bony fish
• Sharks, skates and rays (cartilaginous fish; all are marine)
• Marine invertebrates
What sort of environment does each live in? Describe whether each
group consists primarily of osmoconformers or osmoregulators, and
whether they are ionic conformers or ionic regulators:
Note that freshwater animals all use similar strategies; terrestrial
animals all use similar strategies; but marine animals use highly
diverse strategies. Why are marine animals able to be so variable in
their strategies for osmotic and ionic regulation?
Concept 40.1 Excretory Systems Maintain Homeostasis of the Extracellular Fluid
Which of the following animals is an osmoconformer?
a. A shark
b. A lake trout
c. A dolphin
d. A marine tuna
e. Both b and d
Concept 40.2 Excretory Systems Eliminate Nitrogenous Wastes
A problem at the aquarium
Imagine that you are managing a large salt-water aquarium
that contains numerous species of bony fish, along with a
few sharks and sea turtles. One day the aquarium’s
water filtering system fails. Ammonia starts to build up in
the water.
Working in small groups, discuss these questions:
1. Why is ammonia building up in the water?
2. If the ammonia concentration continues to rise, will
the bony fish, the sharks, and the sea turtles all still
be able to excrete their nitrogenous wastes? Explain.
3. Predict what will happen next. Which animals will
show health problems, why, and in what order?
Concept 40.2 Excretory Systems Eliminate Nitrogenous Wastes
Which of the following animals produces urea as its
principal nitrogenous waste?
a. A shark
b. A lake trout
c. A dolphin
d. A sea turtle
e. Both a and c
Figure 40.2 Waste Products of Metabolism
Figure 40.5 The Vertebrate Nephron
Figure 40.7 The Human Excretory System
Figure 40.7 The Human Excretory System (Part 1)
Figure 40.7 The Human Excretory System (Part 2)
Figure 40.7 The Human Excretory System (Part 3)
Figure 40.8 Concentrating the Urine
Figure 40.8 Concentrating the Urine
Figure 40.9 Renin-Angiotensin-Aldosterone System Helps Regulate GFR
Figure 40.9 Renin-Angiotensin-Aldosterone System Helps Regulate GFR
Figure 40.10 ADH Induces Insertion of Aquaporins into Plasma Membranes
Figure 40.10 ADH Induces Insertion of Aquaporins into Plasma Membranes
Figure 40.10 ADH Induces Insertion of Aquaporins into Plasma Membranes (Part 1)
Figure 40.10 ADH Induces Insertion of Aquaporins into Plasma Membranes (Part 2)
Concept 40.5 The Kidney Is Regulated to Maintain Blood Pressure, Blood Volume, and Blood
Composition
A marathon tragedy
Long-distance runners are often advised to drink as much water as possible
during a marathon, to prevent dehydration. However, a 2002 study of Boston
Marathon runners found that 13% of runners actually had the opposite
problem, hyponatremia - a very low concentration of Na+ in the blood (i.e.,
they had drunk too much water). According to the researchers’ results,
about 90 runners in the Boston Marathon that day probably developed
dangerously critical hyponatremia. Coincidentally, and tragically, on the very
day of the study, 28-year-old runner Cynthia Lucero (who was not part of the
research study) collapsed just a few miles from the finish line, and later died
at a hospital from hyponatremia and associated brain swelling.
1. Consider what homeostatic mechanisms will come into play if you drink a
large volume of water. How will your body detect what has happened? Will
levels of angiotensin, ADH, and ANP increase or decrease? What will each
of these hormonal changes accomplish?
2. The researchers identified a simple method by which runners can rapidly
assess if they might be developing hyponatremia, without needing a blood
sample. Can you guess what it was? [Hint: The runners have to do one thing
before the race, and certain equipment must be available along the
racecourse.]
Concept 40.3 Excretory Systems Produce Urine by Filtration, Reabsorption, and Secretion
Two ants with two problems
1. Imagine that an ant has developed an unusual problem with its
excretory system. It loses the ability to actively transport Na+ and K+
in its hindgut and rectum. (Ion transport elsewhere is normal.)
• Will the ant still be able to excrete its nitrogenous wastes?
• Will it experience any serious problems with its osmotic balance?
• Can this ant do anything that will increase its chances of
survival?
2. A second ant develops a different problem. This ant can’t transport
Na+ or K+ in the Malpighian tubules, but ion transport in the hindgut
and rectum is normal.
• Will the ant be able to excrete its nitrogenous wastes?
• Will it experience any serious problems with osmotic balance?
• Can this ant do anything that will increase its chances of
survival?
3. If you had to be one of these ants, which ant would you rather be?