- General
- What is animal physiology? You might consider how animal physiology
relates to other biological disciplines, the current approaches
used in animal physiology, and the most important modern questions/problems
in animal physiology.
- Write three exam questions for next week's exam. Try to
write questions that model some of the approaches that we have
been taking during this class (structure/function, comparative,
experimental process, disease/disorder, environmental stress).
- Ion transport
- It is the year 3000, and you are a new assistant professor in
the interdisciplinary program in Extraterrestrial Studies at Kenyon
College. Your specialty is comparative extraterrestrial physiology.
Your current research is investigating the mechanisms of water
transport in two shrimp-like animals (SLA1 and SLA2) that were
gathered on a recent collecting trip to an earth-like planet in
a nearby galaxy. In particular, you are interested in how water
moves across the epithelial cell layer that lines to lumen of
their gut. You have done the following experiment: The gut epithelial
cell layers of SLA1 and SLA2 were isolated and placed into an
experimental chamber. An osmotic gradient (Dp) was placed across
the cell layer and water flux (JH2O) was measured during the next
minute. The numbers below indicate JH2O when an osmotic gradient
of 10 mosmol l-1 was applied to an equal cell layer area from
each species. A positive JH2O represents water flux in the direction
of the osmotic gradient (i.e. towards higher osmolarity).
Experiment 1.
Species: JH2O (picoL s-1)
SLA1 3.2 +/- 1.2
SLA2 1.3 +/- 0.9
After the experiment was performed, it was confirmed that no
major change in the overall osmotic gradient across the cells
occurred during the experiment.One the next page, state two
hypotheses that could explain the difference in water flux between
the two species in Experiment 1. For each hypothesis, describe
how the hypothesis could explain the difference in water transport
between SLA1 and SLA2. Then, indicate the important differences
between the two hypotheses.
- Consider a cell with the following transport systems: a Na-K-ATPase
(sodium pump) and a Na-Ca exchanger (antiporter). The Na-K-ATPase
can be blocked by the inhibitor ouabain. What would happen to
the calcium concentration of the cell after application of ouabain?
Explain your answer.
- You are part of a research group that studies the physiology
of the Australian acid-spitting warthog. You have found that this
peculiar animal secretes an acidic solution from a gland in its
mouth. However, the mechanisms of acid (hydrogen ion, H+) transport
across the apical membrane of the cells of this gland are controversial.
You believe that apical H+ transport is via a Na+/H+ exchanger.
Your competitors believe that transport is through an acid (H+)
channel. Describe the experiments that you would perform to prove
that apical transport is via a Na+/H+ exchanger rather than through
a channel.
- Read the reserve reading for this week: Meinild, et al.
The human Na-glucose transporter is a molecular water pump. J.
Physiol. 508: 15-21, 1998.
click here for online access. Now suppose you want to write
a critique of this article. What background information
would you want to have before writing the critique? Try
to be specific in identifying all of the information you would
need to fully analyze the paper.
- A cell is removed from its normal environment (300 mOsm/kg water)
and placed in a more concentrated solution (450 mOsm/kg water).
Describe:
- The effect of this solution change on the cell.
- The reflex pathways that will offset the effects of this
solution change. Be a complete as possible in describe the
reflex paths.
- You are part of a research group that is studying the physiology
of an interesting epithelial cell in the kidney. This cell can
transport Na and Cl ions and water from the kidney tubule fluid
(apical side) to the blood (basolateral side). Your group has
identified a protein that you believe to be important in the transport
process. You have guessed the protein is a Na-Cl cotransporter.
Suppose that you are able to study the protein in isolation (let's
say that you can insert it into an artificial plasma membrane
vesicle where no other transport processes occur) and you are
able to measure transport rates of Na and Cl ions. Describe the
experiments you would perform to prove that you have a Na-Cl cotransporter.
Your expeirments should prove that your protein is a cotransporter
(as opposed to channel, pump or exchanger) and that it co-transports
Na and Cl.
- Describe the events that will occur if a healthy cell is placed
in a hypotonic solution (let's say 150 mOsm). Describe the immediate
effects to the cell and the cell's regulatory response (including
detection of the disturbance and effector mechanisms for re-establishing
homeostasis). Consider the possibility that multiple pathways
may be involved.
- Ouabain is a drug that inhibits the Na-K-ATPase. Describe
what happens to a cell if ouabain is applied. Describe the
direct effects of ouabain and also describe the negative feedback
paths that would act to counter the disturbance.
- Imagine a cell that expresses three times as many sodium pumps
(Na-K-ATPases) as a normal cell and assume that the additional
pumps act functionally exactly as normal sodium pumps (i.e., they
have the same rate of activity and they are regulated in a similar
fashion)..
- Describe the consequences to the cell of tripling sodium
pump activity.
- Describe regulatory pathways that would act to offset the
consequences.
- You are part of a research group that is studying the physiology
of an interesting epithelial cell in the kidney. This cell can
transport Na and Cl ions and water from the kidney tubule fluid
(apical side) to the blood (basolateral side). Your group has
identified four proteins that you believe to be important in the
transport process. You have guessed that these proteins are: Cl
channels, Na channels, K-Cl cotransporters, and Na-K-ATPases.
Suppose that you are able to study each protein in isolation (lets
say that you can insert them into an artificial plasma membrane
vesicle where no other transport processes occur) and you are
able to measure transport rates of Na and Cl ions.
- What experiment(s) would you perform to prove that your
putative Cl channel is in fact a Cl channel? (Hint: you need
to prove that it is not a carrier or a pump). You don=t need
to give specific details of the experiments, just give the
purpose, strategy, and expected results of each experiment.
- What experiment(s) would you perform to prove that your
putative K-Cl cotransporter is in fact a K-Cl cotransporter?
- What experiment(s) would you perform to prove that your
putative Na-K-ATPase is in fact a Na-K-ATPase?
- Develop a working hypothesis that could explain the observed
ion transport capabilities of these cells based on the transport
proteins you have identified (Cl channels, Na channels, K-Cl
cotransporters, and Na-K-ATPases). Draw a picture of the cell
and label it carefully. Explain how your model cell would
transport Na, Cl and water from the apical to the basolateral
side.
- Muscle
- Why can't muscles be fast and powerful and fatigue resistant?
Use your textbook and the reserve reading as sources. You
may focus your answer on a particular aspect of the contractile
system.
- How would the physiological and structural properties of the leg
muscles belonging to world-class marathoners, 400 meter runners,
and high jumpers differ? Be sure to relate structure to function.
- Compare activation of muscle contraction in the rattlesnake
shaker muscle, fish red muscle, and fish white muscle. Link
structure to function.
- Give an example of how muscle properties can change during the
life of an individual animal and an example for how skeletal muscle
function differs among different species. In each example,
relate the structural properties of the skeletal muscle to the function
of the muscle.
- Molluscs such as clams and mussels can protect themselves by closing
their shells tightly using muscles called retractors. Imagine a
starfish attacking a mussel. The starfish tries to pull the mussel
shells apart. During these "endurance contests" the mussel
retractor muscles remain in a contracted state called catch. During
catch, the retractor muscles remain contracted but expend almost
no energy. Using your understanding of myosin and actin interactions,
propose an explanation that could explain the catch state of mussel
muscles.
- Indicate how the length-tension relationship supports or contradicts
the sliding filament theory for muscle contraction.
- Describe the effect of each of the following defects on muscle
function. Describe only how the defect will influence muscle function
and explain why it will have that effect. Do not describe reflexes
that will offset the defects.
- A reduction by 50% in the number of Ca++ pumps (Ca++-ATPases)
in the sarcoplasmic reticulum membrane of rattlesnake shaker
muscle.
- A reduction by 75% in the number of Na+-K+-ATPases in the
axon of the motor nerve that innervates tuna normal swimming
muscle (red muscle, Type I).
- A reduction by 50% in the number of actin filament proteins
in the gastrocnemius muscle (jumping muscle) of the frog.
- For each of the four muscle types below, describe the important
functional properties of each muscle type (focus on how the muscle
differs from other muscle types), and then describe the structural
and physiological properties that enable that muscle type to achieve
its particular function.
- Frog jumping muscle.
- Smooth muscle that surrounds the digestive tract.
- Red muscle of fish responsible for normal, slow, swimming.
- Muscle that produces shaking of rattle in rattlesnake. (Needs
to contract and relax rapidly).
- Movement of ions across cell membranes is an important component
in the regulation of skeletal muscle contraction. Listed below are
ion transport proteins involved in the regulation of contraction.
For each protein, 1) describe its function (how does it contribute
to regulation of contraction?), and 2) describe what would happen
if expression of the protein were reduced substantially (how would
the regulation of contraction be affected?). Be as specific as possible.
- Voltage-dependent K+ channels in the motor neuron.
- Voltage-dependent Ca++ channels in the motor neuron synaptic
terminal.
- Acetylcholine receptors.
- Sarcoplasmic reticulum Ca++ channels.
- Sarcoplasmic reticulum Ca++ pumps.
- Endocrine/nervous system
- Why do animals need an endocrine system and a nervous system?
Wouldn't one control system be enough?
- Discuss the use of chemical messengers in different parts of the
body's regulatory systems (i.e central nervous system, peripheral
nervous system, endocrine system, cellular second messengers).
Why do some of these systems use many different chemicals, while
others use only a select few?
- Like the central nervous system, intracellular signalling pathways
can serve as mechanisms for the integration of information. Compare
and contrast integration of information by intracellular signalling
pathways and the central nervous system.
- Compare and contrast the pathways of hormone release from the
anterior and posterior pituitary. State the functional relevance
of structural differences.
- We discussed at least three different kinds of neuroendocrine
pathways in class, including those involving the posterior pituitary,
the anterior pituitary, and the adrenal medulla. Compare and contrast
these three effector systems. Where possible link structural differences
to functional consequences.
- You belong to a research group that studies the kidney physiology
of an obscure vertebrate called Mastico spearimentus. These animals
have a bizarre diet and sometimes accumulate high level of a small
positively charged molecule called GUM in their blood. These animals
remove GUM by secreting it into the kidney lumen from the bloodstream.
You have found that these animals are capable of removing almost
all of the GUM from the kidney bloodstream and thus must be able
to transport GUM uphill against large concentration gradients. In
the absence of transport proteins, GUM does not move through cell
membranes. This is essentially a fictitious scenario - it does not
necessarily correspond exactly to anything that really happens in
a real animal. In the questions below, I am asking you to suggest
possible hypotheses that would describe the observed results. You
can invent components (i.e cell surface receptor B or glucose-GUM
cotransporter protein) and/or use components from your lecture notes
or the textbook (acetylcholine receptor or sodium pump). Be sure
to describe the structural and functional features of any component
that you invent as well as possible. There is more than one correct
answer. Your job is to make a convincing case for the hypotheses
you propose.
- You have pinpointed an epithelial cell in the lining of the
kidney that you believe is responsible for the transport process
and have found that the transport process is inhibited by ouabain.
Intriguingly, secretion of GUM is dependent upon the presence
of sodium ions in the kidney lumen. Propose a model for secretion
of GUM by the kidney epithelial cells using an appropriate combination
of channels, carriers, and/or pumps. Describe how the cell could
accumulate GUM in the lumen against a concentration gradient
and why luminal sodium is required for transport.
- The GUM secretion process is regulated very tightly. Normally,
GUM transport occurs at a very low basal level. Directly after
a large meal, a two-pronged activation of GUM transport is observed:
an initial increase occurs within 1-2 minutes while a further
increase occurs over 30-90 minutes. Interestingly, lesions in
the hypothalamus have been shown to block the slow activation,
but not to block the fast activation. Propose reflex mechanisms
that could account for the observed activation of the transport
process (i.e. how is the transport process activated after a
meal?). Describe the reflexes completely including cellular
level responses. Correlate form to function.
- One of the reasons that your group has decided to study Mastico
spearimentus is that it has a particularly robust activation
of GUM secretion. You have also studied GUM secretion in its
close relative Mastico wintergreenus. M wintergreenus has the
same level of basal GUM secretion as M. spearimentus. However,
M. spearimentus shows ten-fold greater activation of GUM secretion
following a meal compared to M. wintergreenus. Discuss possible
differences between the two species that might account for the
observed differences in activation. Cite specific structural
features that could account for the observed functional differences.
- During the flight or fight response, both nerve and (neuro)endocrine
efferent pathways are activated.
- Give examples of two different efferent nerve pathways, and
compare their structure and function.
- Give examples of two different neuroendocrine or endocrine
efferent pathways, and compare their structure and function.
- Explain why both nerve and (neuro)endocrine efferent pathways
are needed for an effective flight or fight response.
- Contrast the signaling pathways in each pair below. Contrast the
mechanisms of the pathways and the functional implications of differences
between the pathways.
- Lipid-soluble hormones / lipid-insoluble hormones
- Autonomic nervous system / somatic nervous system
- Anterior pituitary hormones / posterior pituitary hormones
- Neural efferent pathways / endocrine efferent pathways
- Digestion, gut, energy metabolism.
- Interpret figure 2 in the reserve reading assignment (Weiss et
al.) click
here for online access.. Describe the result completely,
state what conclusions can be drawn, and link the conclusions to
the function of the gut.
- Optimal design of the gastrointestinal system would predict that
animals retain food in their gastrointestinal system for exactly
the length of time it takes to digest it. Longer than necessary
retention times would prevent new food from entering and being digested,
shorter than needed times would reduce digestion efficiency. Design
an experiment to test whether retention times are optimal.
Your experiments may utilize comparisons among species and/or experiments
performed within a single species. Discuss your choice of
experimental animals, the experimental protocol, the measurements
you would need to make, and possible problems in interpretation.
- After an animal has begun a meal, how does it know when to stop
eating? What factors influence the decision to stop eating?
- Imagine two strains of transgenic mice. One lacks the ability
to produce leptin, the other lacks the ability to produce insulin.
Compare and contrast the effects of leptin deficiency and insulin
deficiency. Consider effects at both the central nervous system
and the other tissues.
- Just to keep your pet cat off-guard, you abruptly replace her
food with a similar-looking food
that has twice the caloric content. (Editorial note: this is a purely
fictitious scenario, I have never done this to Petunia). You find
that your cat does not gain any weight. Discuss the reflex paths
that are involved in this weight regulation. Be sure to discuss
all possible responses that would contribute to maintenance of body
weight.
- It might be expected that animals that eat a diet that is very
high in total nutrient concentration and contains mostly protein
would have digestive systems with very different properties than
animals that eat a diet that is much lower in total nutrient concentration
and contains mostly carbohydrate.
- Predict what the properties of the digestive system of each
species will be, focusing on aspects that will be different
between the two species. Consider as many of the specific functions
of the digestive system as possible.
- Suppose that you can measure two quantities, retention time
and extraction efficiency. Design experiments to test the predictions
that you have made. Describe the experimental strategies and
the predicted results (based on answer to part a).
- Circulation
- Discuss the functional and structural similarities between the
heart of a turtle and a mammalian fetus.
- In class we discussed blood flow through arteries as if arteries
are "ideal" rigid cylinders. In what ways is our consideration of
arteries as rigid cylinders an oversimplification? How can these
more complex properties of arteries increase susceptibility to stroke?
- Describe the physical response and reflex regulation that occurs
when one liter of blood is withdrawn from the human circulatory
system.
- What stresses are placed upon the circulatory system during a
15 mile run on a hot day? Describe the reflex compensation of the
system.
- Discuss the physical effects on the human circulatory system of
acutely removing 25% of the blood volume. Do not describe the reflexes
that will offset these effects, rather describe the physical effects
in each region of the circulation completely.
- Discuss the responses in the circulatory system that would act
to offset the effects of removing 25% of the blood volume. Consider
reflex regulation of each part of the system - veins, heart, cappilaries,
arteries. Consider the complete reflex arc.
- Compare and contrast arteries and veins. Show how structural
differences lead to differences in function.
- During aerobic exercise, oxygen use by the muscles increases and
this is matched by increased oxygen delivery to the muscles. Many
mechanisms are involved in the increased oxygen delivery. Some involve
regulation by the nervous system; others are responses that will
occur without involvement of the nervous system. Describe the mechanisms
that will increase muscle oxygen delivery without direct involvement
of the nervous system.
- When you wake up for Biology 341, it is a nice pleasant 55oF,
so you leave your jacket in your room. However, given spring weather
in Ohio, something happens during class and it is 35oF and sleeting
when you leave class. When you walk outside, there is a massive
vasoconstriction in the arterioles of your skin (this is a thermoregulatory
response, reducing skin blood flow limits heat loss to the environment).
- What are the cardiac consequences of this vasoconstriction?
Diagram a full negative feedback loop as part of your answer.
- Imagine a similar scenario in a person whose muscarinic ACh
receptors in the sino-atrial pacemaker cells of a cat are reduced
greatly. How would this affect the regulatory response described
above? Be as specific as possible about the mechanism.
- Three organisms are listed below. For each organism, imagine that
pulmonary (gill or lung) vascular resistance is increased. Briefly
describe the effects of the increased pulmonary resistance. Consider
effects on pressures, oxygenation of the blood, and flow patterns.
- A marine bony fish (teleost).
- The frog.
- A mammal.
- You go to the Red Cross to give blood (about 1 pint, or 400 ml,
is the standard "donation").
- Describe the cardiovascular effect(s) of losing 400 ml of
blood.
- Describe the complete reflex pathways that will offset these
effect(s). Consider both cardiovascular and renal responses.
- When a human stands up from a supine (lying down) position, heart
rate usually increases. Why? Be as complete as possible in your
description of the mechanism.
- Compare and contrast the circulatory systems of the following
animals. Show how the structural and physiological differences relate
to the functional differences between animals. Where possible, show
how the features of the circulatory system relate to the respiratory
system.
- a teleost fish (i.e salmon) and a terrestrial mammal (i.e.
Petunia).
- a terrestrial insect (i.e. grasshopper) and a terrestrial
mammal.
- a human training to run the Columbus marathon and a "couch
potato".
- In an experimental system, suppose you could manipulate the plasma
protein content of the blood of a mammal. Remember that plasma proteins
are the primary determinant of the oncotic pressure (protein osmotic
pressure) of blood.
- Describe the factors that influence fluid filtration at the
capillary level.
- Describe the effects that doubling plasma protein content
would have on fluid filtration and on the circulatory system
overall.
- Describe the reflex systems that will act to offset the effects
of doubling plasma protein content.
- Draw schematic representations of the mammalian circulatory system
and the fish circulatory system. Label your drawings.
- How does the structure of the mammalian circulation differ
from that of amphibians?
- How does the structure of the fish circulation differ from
that of amphibians?
- What are the advantage(s) and disadvantage(s) of the mammalian
circulatory plan compared to those of other vertebrates? Describe
the functional significance of these advantage(s) and disadvantage(s).
- Suppose a bolus of whole blood with a volume of 20% of the total
blood volume is injected into a dog=s circulatory system. This increase
in blood volume will cause increased blood pressure throughout the
circulation. For each part of the circulation shown below: 1) Describe
the physical effects that will result from the increased pressure
(an equation or drawing may help). 2) Describe the regulatory mechanism(s)
specific to each area that will act to reduce the increased pressure
(focus on the efferent rather than the afferent pathways). Consider
neural-mediated and local reflexes. 3) If they exist, describe positive
feedback loops that would act to increase the pressure further.
- The heart
- The arteries (and arterioles)
- The capillary beds
- The veins
- Suppose the blood volume of a dog is reduced by 20% through bleeding.
This decrease in blood volume will cause decreased blood pressure
throughout the circulation. Describe the reflex paths and mechanisms
that will lead to each of the regulatory effects given below.
- Glomerular filtration rate is decreased.
- Reabsorption of sodium chloride is increased. (Give all possible
mechanisms).
- Reabsorption of water in the collecting duct is increased.
- Explain why water reabsorption is dependent upon the countercurrent
multiplication system in the loop of Henle (descending limb
and thick ascending limb
- Ion and salt balance
- Terrestrial vertebrates may have evolved from seawater or freshwater
aquatic vertebrates (let's exclude the in-between estuarine vertebrates
for the sake of this question). From a physiological perspective,
which transition is more difficult: freshwater to terrestrial
or seawater to terrestrial?
- In the article "political science of salt", many epidemiological
studies were used to argue about whether or not salt reduction
will reduce blood pressure in the general population. Based
on what you know about renal physiology, from a theoretical standpoint,
does it make sense that moderate reductions in salt intake will
cause blood pressure reductions?
- Average salt intake is about 10 grams per day for Americans.
Discuss the physiological consequences of lowering salt intake
to 2.5 grams per day.
- Compare the osmoregulatory (salt and water balance) problems
of the following animals: a marine mammal, a seagull that eats
marine invertebrates, and a human running a marathon in August.
Briefly discuss the general responses of each animal to its particular
problems.
- A freshwater fish is placed into saltwater. What problems
will this fish have? What factors will affect the ability
of the fish to respond to these problems?
- For each scenario listed below, describe in one sentence or
phrase what would happen to urine output or composition. If the
effect would only be observed under particular conditions, then
state those conditions. Then, in one or two sentences, describe
why. Consider only the direct effect of the stated scenario. Do
not consider reflex responses that would act to counter the initial
effect.
- Treatment with the drug furosemide, which blocks Na-K-Cl
cotransporters in the thick ascending limb and therefore blocks
active Na-Cl transport by that tissue.
- An increase in arterial blood pressure. (consider direct
effects on kidney, not the reflex regulatory pathway).
- Excessive consumption of alcohol, which inhibits the secretion
of vasopressin (also called ADH) from the posterior pituitary.
- For each of the following scenarios, describe the direct effect
on the final urinary output in one or two sentences. Assume that
other reflexes do not offset the effects. If the scenario will
only produce an effect under specific conditions, then state those
conditions.
- An increase in blood pressure in the renal glomerulus.
- A dramatic decrease in proximal tubule Na-glucose cotransporters.
- A decrease in the number of Na-K-Cl cotransporters in the
thick ascending limb.
- A decrease in the number of aquaporin water channels in
the cortical collecting duct.
- A decrease in the secretion of aldosterone by the adrenal
cortex.
- You are the science officer in the new Star Trek series (Star
Trek Forever: One More Time). You don't really figure into the
plot line of most episodes, so you spend most of your time examining
the salt and water balance physiology of organisms that you pick
up from various worlds. Your current project is a crustacean-like
invertebrate from the toxic waste dump planet Radox 4. You think
the little critter has a filtration-based excretory organ. What
advantages and disadvantages would this system have (compared
to a secretory organ)? What experiments would you perform to prove
that the critter has a filtration rather than a secretory excretory
organ?
- At some point in evolutionary history, aquatic vertebrates must
have made an evolutionary transition to terrestrial life. One
major problem that needed to be overcome is salt and water balance
in the terrestrial environment.
- Describe the salt and water balance problems associated
with terrestrial life.
- Describe the salt and water balance problems in a saltwater
aquatic animal transition to terrestrial and compare them
to the problems of a freshwater to terrestrial transition.
Do you think it is more likely that terrestrial animals evolved
from freshwater or saltwater aquatic animals? Explain why.
- Describe physiological adaptations that might enable an
aquatic vertebrate to begin to enter the terrestrial environment.
Consider salt and water balance only.
- Mammals live in freshwater, in saltwater, and on land. Each
of these environments poses a particular set of problems for salt
and water balance. For each of the mammals listed below: a) discuss
the problems the organism faces in maintaining salt and water
balance, and b) discuss the mechanisms the organisms utilize to
counter these problems.
- A desert rat.
- A beaver (freshwater).
- A blue whale (salt water).
- Filtration and secretion are two different mechanisms for the
creation of a primary fluid in osmoregulatory organs (such as
the mammalian kidney and the insect Malpighian tubule).
- Compare and contrast the mechanisms of filtration and secretion.
Discuss both similarities and differences. How does the composition
of the primary fluid differ between the two mechanisms?
- What are the functional advantages of a filtration system?
- What are the functional advantages of a secretion system?
- Describe two experiments that would demonstrate that a particular
system utilizes secretion rather than filtration. Describe
both the experiments and the predicted results
- Respiration
- Three techniques for measuring aerobic dive limit are given
in Burns and Castellini click
here for online access. Compare and contrast these three
methods - which is the best?
- Diving and high altitide are both situations where oxygen might
become limited. Discuss the differences between these situations
and how those differences will affect physiological responses.
- Adult insects have a tracheal system for delivering oxygen to
the tissues. How well would a tracheal system work for an
aquatic animal? Explain your answer.
- Exercise and altitude both may cause reduction in tissue oxygen
availability. Compare and contrast the regulation of breathing
during exercise and during altitude exposure.
- Athletes sometimes train at altitude in an attempt to improve
sea-level performance. Precisely why would training at altitude
improve sea-level exercise performance?
- During aerobic exercise, oxygen is used more rapidly and carbon
dioxide is produced more rapidly than during rest. Describe how
the respiratory system responds to these demands during exercise.
Be careful to consider responses at each step of the respiratory
process. Describe complete reflex pathways where appropriate.
- Four hypothetical defects in human respiratory system function
are listed. Very completely describe the physiological effect(s)
of the defect and briefly describe how the effects might be countered
by physiological responses.
- a dramatic reduction in lung surfactant.
- an obstruction in the lung that redirects air flow entirely
towards one half of the lung.
- a mutation in the hemoglobin gene that substantially increases
the affinity of hemoglobin for oxygen.
- a loss of function mutation in the Cl-bicarbonate exchange
protein in RBCs.
- Although water contains very low level of oxygen compared to
air, fish carry out active lifestyles in the aquatic environment.Compare
and contrast the gills of fish to the suction pump of mammals.
What is the mechanism of convection in each? How does the structure
of the fish respiratory system allow fish to be active in the
aquatic environment?
- Most fish will not survive for long if they are taken out
of water. Why do fish suffocate in the air, when the air has
a much higher oxygen content than the water? Suggest one adaptation
that might allow fish to survive for longer
- periods of time outside of water.
- Some fish (i.e. tuna) are obligate swimmers. Why will these
fish suffocate if they are prevented from swimming for a long
period of time?
- If humans try to breathe water, they will quickly drown.
Why? (Give at least two reasons).
- You are writing the script for the next episode of the new Star
Trek series (Star Trek Again: The Voyage Persists). In the opening
passage of the episode, a landing team (all humans) exploring
an unknown planet discovers that there are very low levels of
oxygen in the atmosphere. After chasing away some big slimy monsters
that throw styrofoam rocks, the landing team decides to establish
a permanent science base on the planet.
- Describe the acute responses (occurring within one day)
to low atmospheric oxygen you might expect to find in the
respiratory systems of the landing team. Consider responses
in the entire respiratory system ( including the circulatory
gas transport system). Discuss the interaction between oxygen
regulation and carbon dioxide regulation in the body during
this acute exposure.
- The landing team stays for two months on the new planet.
Describe the chronic responses that might occur in the landing
team's respiratory systems. Again, consider the entire respiratory
system. How might the interaction between oxygen regulation
and carbon dioxide regulation in the body have changed since
the acute exposure?
- Suppose humans remain on the planet for one million years.
Suggest (at least 2) possible evolutionary adaptations that
might enable the descendants of the landing team to breathe
more efficiently or more effectively on the low-oxygen planet.
You may suggest new anatomical features, or changes in the
fundamental mechanisms of the human respiratory system
- Integrative
- Choose one physiological challenge that parasites face, and briefly
describe mechanisms that they use to overcome the physiological
challenge.
- You are junior science officer on the new Star Trek series, Star
Trek Eternity: It will never end. You are on shore leave on the
spectacular vacation plant, Hedon 7. The warm side of Hedon 7 almost
always faces the sun and has famous beaches. The cold side receives
little sunlight and temperatures fluctuate seasonally. During most
of the year, the temperature on the cold side is positive 5oC, but
it drops to negative 30oC for about 3 months every year. The skiing
is spectacular on the cold side. Shuttle buses run between the two
sides of the planet, and it is one of the few places in the universe
where you can come off the slopes and minutes later take a dip in
the ocean! Despite the Captain's admonitions to relax, you've been
doing a bit of collecting and have discovered two highly related
species of salamander (an ectotherm). Species 1 lives only on the
warm side and dies when moved to the cold side (you tried it!).
Species 2 lives only on the dark, cold side. Your careful biochemical
analyses reveal that the only difference between the two species
is a single protein that is found in the blood of Species 2. Give
two hypotheses about the function of the protein and indicate how
each hypothesis relates to the survival of species 2 on the dark
side of the planet.
- As far as I can tell, my cat Petunia is a world-class thermoregulator.
In fact, on some days, thermoregulation seems to be Petunia's major
activity. The scenarios below are fictitious. We love Petunia and
would never do anything to harm her.
- Suppose that Petunia is exposed to the cold. Describe adaptations
or responses that would occur on each of the time scales given
below. For each response or adaptation, state whether it is
behavioral, passive, or active.
- -acute (occurs over seconds to minutes)
- -chronic (occurs over days to months - i.e. winter vs.
summer)
- -evolutionary adaptation (occurs over millions of generations)
- Suppose that Petunia is exposed to heat. Describe adaptations
or responses that would occur on each of the time scales given
below. For each response or adaptation, state whether it is
behavioral, passive, or active.
- -acute (occurs over seconds to minutes)
- -chronic (occurs over days to months - i.e. winter vs.
summer)
|
