Final

Question 1

Conformer

Answer 1

Internal conditions change with the external conditions keeping them relatively equal.
Ex: Thermal conformers increase their body temp when external temp increases

Question 2

Homeostasis

Answer 2

Internal constancy; a dynamic mechanism that works to maintain the stable conditions of an organism to keep its functions efficient

Question 3

Hormone

Answer 3

A signaling molecule released by non-neuronal endocrine cells or neurons (neurohormones) that travel through the bloodstream to target cells. Usually does not take a lot of hormones to get a response. Mostly involved in long-distance signals.

Question 4

Negative Feedback

Answer 4

A downstream signal/response inhibits/reduces a more upstream signal/response in the same pathway

Question 5

Acclimation/Acclimatization

Answer 5

Types of phenotypic plasticity associated with the chronic physiological timescale. The only difference between them is that acclimation is phenotypic plasticity occurring in a more controlled/lab setting and acclimatization occurs in nature/wild settings

Question 6

2nd Law of Thermodynamics

Answer 6

A system will continuously become more disordered unless an outside source of energy is acting on it

Question 7

Thermoregulation

Answer 7

Maintenance of a relatively stable internal body temperature that is suitable for an organism’s function and survival

Question 8

Q10

Answer 8

Factor by which physiological condition will change after a 10-degree temperature change

Question 9

Aerobic Scope

Answer 9

Aerobic scope = MMR-BMR
The range of aerobic metabolism an organism is capable of

Question 10

Maximal Aerobic Speed

Answer 10

MR will increase as speed increases up to a point. This point is the maximal aerobic speed

Question 11

CORT-Fitness Hypothesis

Answer 11

In reference to baseline CORT concentrations. The relation between stress and CORT and the relation between stress and fitness show that COR and fitness have a negative relationship. This hypothesis is not always true and other factors must be considered

Question 12

Sarcomere

Answer 12

Component of muscle cells consisting of thick (myosin) and thin (actin) filaments. The sarcomere is involved in muscle contractions

Question 13

Cooperativity

Answer 13

In reference to hemoglobin (Hb). A partially bound Hb molecule has high O2 affinity compared to a completely unbound Hb molecule.

Question 14

Sliding Filament Theory

Answer 14

Explains how muscles contract. Myosin from the thick filaments pulls the thin filaments toward the middle, causing the sarcomere to shorten (contraction)

Question 15

Tidal Ventilation

Answer 15

Type of convectional flow in which the medium enters and leaves the same passageway. Fresh media mixes with stale media

Question 16

What is meant by the oxygen cascade and why is it important?

Answer 16

The O2 cascade describes how PO2 decreases from ambient air to mitochondria. This is important for proper and efficient gas exchange since it is dependent on partial pressure. O2 likes moving from a high PO2 to a low PO2

Question 17

Briefly explain the Bohr Effect and it’s significance

Answer 17

The Bohr effect is a right shift due to a change in pH. It describes the relation between pH and O2 binding affinity. When pH is high, binding affinity is high, and vice versa. This is important when considering picking up and releasing O2 in the body. For example, arterial tissues have a high pH so O2 can bind Hb. In venous tissues, the pH is lower so Hb will release O2 to the tissue.

Question 18

Describe the excitation-contraction coupling process

Answer 18

1. AP causes exocytosis of Ach and Ach binds the ligand gates channel to open it
2. Na2+ flows in through the channel and causes an AP. The AP causes T tubules to be depolarized and then depolarizes DHPR, causing a conformational change
3. RyR Ca2+ channel opens
4. Ca2+ binds to troponin, initiating the sliding filament theory
5. AChE hydrolyzes ACh, closing the Na2+ and Ca2+ channels
6. When Ca2+ is depleted the contraction ends

Question 19

Compare and contrast co-current and countercurrent gas exchange. Include a discussion of changes in O2 partial pressure in the blood and external medium.

Answer 19

Both cocurrent and countercurrent are convectional, unidirectional flows. Cocurrent media and blood flow in the same direction, eventually reaching an equilibrium. In countercurrent media and blood flow in opposite directions. Blood travels and gradually interacts with media that has a high PO2 than it. Countercurrent gas exchange is more efficient

Question 20

Describe two ways that tension in a muscle is increased to meet the stress placed on it. In other words, what are two mechanisms that allow the modulation of muscle force (tension)

Answer 20

Recruitment: increase the number of active motor units
Temporal Summation: Rapid firing of APs

Question 21

Describe the mammalian stress response starting with a stimulus and include known actions of the stress hormone

Answer 21

Stress triggers and activates both the HPA axis and the sympathetic nervous system. They both cause psychological effects. SNS triggers early physiological effects and the HPA axis triggers delayed physiological effects. Delayed physiological effects enhance some early physiological effects.

Question 22

Briefly explain adaptations and physiological changes that take place during extended dives in diving mammals

Answer 22

Compressing the lung: this helps get rid of some of the buoyancy effects that inflated lungs cause
Bradycardia: slower heart rate
“Brain-Heart-Lung Machine”: blood flow is restricted to those vital organs

Question 23

Compare and contrast osmoregulation in freshwater and marine teleost fish

Answer 23

Freshwater: Hyperosmotic, active transport via gill epithelial for Na and Cl, ingest salts via food, lose salts and water in feces, U/P>1, lose salts via diffusion, gain water through gills via osmosis

Marine: Hyposmotic, ingest salts and water via food AND seawater, lose salts and water in feces, U/P=1, gain salts via diffusion, lose water through gills via osmosis

Question 24

Draw the relationship between metabolic rate and speed during terrestrial locomotion (left graph). Draw and explain how the total cost of transport varies with locomotor speed, and indicate the speed at which locomotion is most economical A (right graph). LABEL AXES

Answer 24

As speed increases, the MR also increases up to a point, this point is the maximal aerobic speed.

The total cost of transport varies with speed due to changes in gait (behavioral change). The most economical transport is achieved when moving closer to the maximal aerobic speed

Question 25

Explain how the thermal sensitivity of O2 consumption responds to temperature in two different time frames

Answer 25

The chronic timeframe response shows that the overall MR is higher in the lizard acclimated to 16 degrees vs the once acclimated to 33 degrees. This is seen by the increased O2 consumption at every point on the 16-degree acclimated line. The difference between the space of the lines indicates that acclimation increases thermal sensitivity in the 16 degrees acclimated lizard.

The acute time frame response shows how the initial rate of O2 consumption is affected immediately after each lizard is acclimated. The 16 degrees acclimated lizard shows a higher rate of O2 consumption, aka a high MR, than the lizard acclimated to 33 degrees at the initial measurement. In the acute timeframe, behavioral changes are first to play a role in thermal regulation.

Question 26

Explain why indirect calorimetry does not always provide a perfect measurement of metabolic rate

Answer 26

Indirect calorimetry is the measurement of MR by measuring O2 consumption and CO2 production, in addition to RQ determination to determine heat production. It is not always perfect because it is not a direct calculation of heat production and relies on aerobic metabolism (cellular respiration) occurring.

Question 27

Using the performance curve, explain how and why physiological function is impaired at milder temperatures than those causing death

Answer 27

Physiological function is impaired at milder temps because of the amount of O2 available. This is specific to aquatic organisms and terrestrial organisms as embryos. As temp increases, the MR also increases, and dissolved O2 begins to decrease. This causes aerobic physiological process efficiency to decrease.

Question 28

Physiology is an integrative discipline. What does this mean? Explain how a physiologist must be an integrative biologist. What are the important considerations one must make when attempting a study of animal physiology? Pose a potential research question aimed at understanding animal physiology and explain how and which different biological subdisciplines would be used to answer the question.

Answer 28

It means that not only does physiology integrate multiple disciplines (Bio, Chem, Physics, Ecology, Evolution), but it also integrated all levels of biological organization. When studying animal physiology it is important to acknowledge the levels of organizations you are interested in as well as the other scientific disciplines that will aid in answering the proposed question.
Q: How do different habitat types impact metabolic function?
For this question, it may be important to understand biology and chemistry as they work hand in hand to accomplish metabolic functions.

Question 29

Synaptic plasticity is involved in the development of long-term memory and learning. Describe what we mean when we say synaptic plasticity, explain with examples the different ways that synaptic plasticity occurs, and describe two mechanisms through which synaptic plasticity operates.

Answer 29

Synaptic plasticity describes when synaptic properties change with time and activity.

In sea slugs forms of learning, like habituation and sensitization were explored, showing real-life examples of synaptic plasticity.

Two mechanisms in which synaptic plasticity operates:
Presynaptically: changes in the rate of NT synthesis, storage, and release
Postsynaptically: sensitivity to NT can be increased or decreased under different circumstances

Question 30

Physiological changes to the external environment occur over varying timescales. Compare and contrast each. Provide an example that demonstrates changes across different time frames.

Answer 30

Acute: Immediate response (smallest scale)
Ex: sweating in response to heat

Chronic: Physiological changes occur after a longer time period (days, weeks, seasons); acclimation/acclimatization
Ex: being in the mountains for a week causes hematocrit to increase which increases O2 binding affinity making breathing easier at high altitudes

Both chronic and acute are reversible and can affect individuals

Evolutionary: Associated with adaptations that come about usually via natural selection (largest scale). It is irreversible and rather than affecting individuals it affects populations over generations
Ex: Finch beak size

Question 31

We know that temperature and body size influence virtually all physiological functions. Explain how scientists study physiological function as it relates to body size. Include in your answer a discussion of how they study allometry.

Answer 31

Body size and scaling are considered when studying physiology because more often than not there is a (+) relationship between the two. Allometry allows us to view proportional relationships. If a relation is isometric then we know that growth is 1:1 and proportions are constant. This means during development dimensions will scale up and down with each other. in allometric growth, organism proportions change in with body size and depend on SA, V, and other physical parameters. The allometric equation (Y=aX^b) gives us insight into the scales exponent (b) when plotted and derived. This can give us insight into proportions and growth rates.
b>1 (not always 1): growth is (+) allometric (Y increases faster than X)
b< 1( not always 1): growth is (-) allometric (X increases faster than Y)
b=1 (not always 1): growth is isometric
Scaling is important when studying physiological function because it refers to the structural and functional consequences that come with changes in body size in otherwise similar organisms.

Question 32

We know that unmyelinated axons conduct action potentials without decrement. However, some known diseases cause demyelination (the breakdown of myelin sheaths). When this happens, the conduction of action potential is severely inhibited. Why do you think conduction is inhibited in rese cases? Here I want you to speculate on the mechanism. Once you have identified the mechanism, speculate on the potential effects of such a myelinating disease.

Answer 32

The conductivity of APs is very dependent on myelination. Myelination is important in preventing ion leakage, insulation, and enhancing AP conductivity speed. The presence of myelin sheaths around axons also allows for saltatory conductivity, meaning the AP can jump from node to node. Myelin sheaths allow APs to travel further and faster. Without myelination, the conductivity of the AP is greatly diminished so APs may not be able to get to the next target. AP responses diminish with increased distance from the stimulation due to leaky channels. Leaky channels are not present in sheath areas so the AP occurs over longer distances. Conduction is inhibited in unmyelinated axons due to the presence of more leaky channels, counteracting the membrane potential. Diseases, like MS, in which myelination is diminished, will eventually cause neuronal function to diminish. This can cause physical movement ability to decrease, making a person wheelchair-bound. It will also cause NT signals to not be transmitted efficiently.