Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

BIOL241 > Topic 8 - Thermoregulation > Flashcards

Topic 8 - Thermoregulation Flashcards

1
Q

Homeostasis

A

regulation of an internal environment in the face of changes in the external environment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Negative Feedback

A

A change in variable triggers a response that opposes the change
LEADS TO HOMEOSTASIS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Positive Feedback

A

change in variable triggers a response that amplifies the change
DOES NOT LEAD TO HOMEOSTASIS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How is metabolic energy used to maintain homeostasis, using temperature regulation as an example

A

activity on hot day results in rise in skin and body temp –> change is detected by temp cells in the skin –> neurons in hypothalamus recieve sensory info and determine if reaction is required–> info is sent along a motor pathway–> metabolically generated heat is conducted to evaporative surfaces, panting is produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Ectotherm

how does it get its heat?

A

acquires body heat from environment, generate metabolic heat but dont keep it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Endotherm

A

uses metabolism to generate body heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

homeotherm

A

maintains constant body temperature, independent of ambient temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

heterotherm

A

body temperature fluctuates with ambient temperature (ex fish whose temp changes seasonally)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How can homeostasis be regulated?

A

Change in behavior or metabolism to maintain internal environment within certain range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

In the regulation of homeostasis, what are parameters that organisms control?

A

pH, water, volume and pressure of cells and blood plasma, osmoregulation, solutes, temperature, O2/CO2, heart rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

With feedback mechanisms, what are the steps?

A

SSIE: stimulus, sensor, integrator, effector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Stimulus

A

external or internal change in a regulated factor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Sensor

A

detects the change in condition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Integrator

A

compares condition to its set point, activates effector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Effector

A

physiological change that returns factor to its set point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Explain temperature regulation as an example of homeostasis

SSIE

A

Stimulus: change in temperature of skin
Sensor: temp detection nerves in the skin
Integrator: Hypothalamus
Effector: Muscle tissue, vasculature, sweat glands

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

explain the positive feedback mechanism of childbirth

A

Stimulus: head of baby pushes against cervix
Sensor: stretch receptors in cervix
Integrator: pituitary gland releases oxytocin
Effector: oxytocin causes the uterus to contract (cervix to dilate), puts more pressure on the sensors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why is thermoregulation important?

A

regulating internal body temperature impacts energy budgets

ambient temperature (Ta) determines how much energy is spent regulating body temperature (Tb)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to body heat in endotherms

generation exchange regulation

A

Heat generation: metabolism
Heat exchange: conduction, convection, evaporation and radiation
Regulation: Tb is regulated by changing conductance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Conductance

A

the rate of heat exchange

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is the relationship between mass and conductance? and why?

A

As body mass increases, conductance decreases

due to the low SA:V ratio. if there is more SA, there is more conductance. Less SA per mass, risks losing less heat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

convection

A

air/liquid for heat transfer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

conduction

A

direct contact heat transfer

24
Q

evaporation

A

loss of heat when water changes from liquid to gas

25
Q

What is the strategy of an endotherm + heterotherm

A

change body temperature seasonally (eg hibernation)

26
Q

what is the strategy of an endotherm + homeotherm

A

Behavioural: seek cool or warmth

Physiological: sweating, panting, shivering

27
Q

what is the strategy of a homeotherm+ectotherm

A

seek or live in stable environments

28
Q

what is the strategy of a heterotherm+ectotherm

A

behavioural: move between sun and shade

physiological: adjust metabolic rate based on ambient temp

29
Q

Regional Heterothermy

A

animals with different temperatures in different parts of their bodies

ex: tuna with high core body temp and exterior muscles at ocean temp

30
Q

what is the metabolic consequence of endothermy?

A

higher mass-specific RMR than ectotherms

Recall: as body mass increases, mass-specific RMR declines

31
Q

Why is temperature important for metaboilism?

enzymes?

A

enzyme activity varies with temperature, influencing body temperature

enzymes at low temps are inactive, reach ideal, high temps they denature

32
Q

What is the relationship between temperature, metabolism, and performance?

A

Temperature drives metabolism, which drives performance

33
Q

How does the response to ambient temperature differ between ecto and endotherms

A

as temperature increases, endotherm stays constant, until denaturation, ectotherm has positive correlation

34
Q

What is the response of a homeothermic endotherm to changes in ambient temperature?

A

RMR starts high, decreases at slope related to conductance, reaches BMR (this is the thermal neutral zone), MR increases to cool down, after a certain point it is hyperthermy

35
Q

What is the TNZ

A

thermo neutral zone is where energy is not needed for regulation

36
Q

Heterothermic ectotherm response to changes in ambient temp

A

starts low, increases constantly (lethargy then activity where temp is optimum), increases too far (hyperthermia)

37
Q

What are strategies to regulate temperature

for homeotherms

A

Below TNZ, thermogenesis (things like shivering, vasoconstriction, decreasing exposure through huddling/burrowing)

Above TNZ, ACTIVE COOLING, panting, sweating

38
Q

What are behavioral regulations of conductance

A

Moving to optimize heat exchange with environment
Changing exposure
Grouping
Migration
Dormancy

39
Q

What is torpor

A

short 6-8 hour reduction in activity, drop in body temp, lower metabolic rate - reduces energy use to stay warm

40
Q

What is hibernation

A

usually done by small mammals, as large SA to V ratio makes it easier to quickly change body temp, awake for 1-2 days periodically

41
Q

Why do animals migrate?

A

Temperature regulation - seeking certain ambient conditions recquires less energy expenditure to maintain body temp

42
Q

Physiological regulation of conductance

A

acclimation, blood flow, insulation, fur length and color change, sweating/panting, cryoprotectants, shivering thermogenesis, non-shivering thermogenesis

43
Q

Acclimation

A

changes to physiological processes that respond (typically to seasonal) temperature changes.

44
Q

What does Acclimation look like for animals, cell membranes and enzymes

A

Animal - more enzyme to compensate lower efficiency
Cell membrane - altered viscosity
Enzyme - change conformation to be more efficient

45
Q

Give an example of acclimation with membrane viscosity

A

If acclimated to 25C, and put at 5C temp, phospholipids will be less saturated to decrease viscosity

If acclimated to 5 and put at 25C, phospholipids will be more saturated to increase viscosity

46
Q

How can blood flow be regulated to affect conductance with environment

A

Vasoconstriction - vessels have less diameter, less blood flow, less heat moves to surface

Vasodilation

47
Q

Explain vasoconstriction, its relation to conductance for endo and ectotherms

A

Decreases conductance with environment

Endotherms: when cold, to retain heat
Ectotherms: when hot, to retain heat

48
Q

Explain vasodilation its relation to conductance for endo and ectotherms

A

increases conductance with environment

Endotherm: when hot, to release heat
Ectotherm: when cold, to increase heat gained from environment (ex hot rocks)

49
Q

Insulation - how is it a strategy for changing conductance

A

can slow the rate of heat transfer

internal: fat/blubber

external: fur/feathers

50
Q

Why do some animals have thicker fur in winter

A

provides more insulation

51
Q

How is fur colouration a thermoregulatory strategy?

A

Dark fur absorbs light, generates heat outside insulation. Heat is lost to environment more easily by convection

White fur allows light to reach skin, generates heat inside insulation layer, skin stays warmer as fur protects its loss

52
Q

What is the purpose of sweating and panting

A

Heat loss due to evaporation

panting increases ventilation which increases heat loss

53
Q

What are cryoprotectants

A

Molecular strategy used by ectotherms

Molecules (like glucose or glycerol) are produced to lower freezing point

Antifreeze properties allow ice to form in extracellular spaces but not internally, prevent sharp edges from crystallization

54
Q

What are the two types of thermogenesis

A

Shivering and Not-shivering

55
Q

Shivering Thermogenesis

A

muscles move rapidly to generate heat, but no movement

56
Q

Non-shivering thermogenesis

A

fat is metabolized by the mitochondria - convert energy into heat rather than ATP

BIOL241 (6 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions