Brainscape's Knowledge GenomeTM

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


See full index

Animal Physiology Exam 1 > Temperature > Flashcards

Temperature Flashcards

1
Q

poikilotherms

A

body temp fluctuates with ambient environmental temps
- as temp inc-> MR inc
- as temp dec-> MR dec

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

ectotherms

A

heat input is obtained from outside organism
- lower vertebrates and invertebrate

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

homeotherms

A

maintain relatively constant body temp despite changes in ambient temp
- dec temp after critical temp-> inc MR
- inc MR-> inc heat production to maintain a constant body temp

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

endotherm

A

where animals use internal metabolic heat production
- birds and mammals

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

thermoneutral zone

A
  • at high temp within this range, MR are lower than expected
  • at lower temp, they’re higher than expected
  • at critical temp, theres a point where MR must inc in order to maintain a constant temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

MR of poikilotherms in Antarctic vs tropics

A

MR are about the same
- MR are similar in the different species at their respective ambient temp
- MR still inc with inc temp

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

how do enzymes get around effects of temperature

A

1) change in enzyme concentration
2) change in type of enzyme
3) modulate enzymes

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

how do enzymes adapt to be more efficient

A
  • changes in catalytic efficiencies (Vmax = Kcat[E])
  • via enzyme-substrate affinities
  • inc Vmax= inc enzyme efficiency
    0 Vmax greater in cold adapted species, activation energy lower too
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Catalytic efficiency (Kcat)

A

how efficient is the enzyme in converting substrate to product per unit time
- enzymes from cold adapted apecies are more catalytically efficient–> lower activation energies (greater Kcat= greater Vmax)

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

enzyme-substrate affinities

A

cold adapted species have lower Km values–> greater substrate affinities–> more of that reaction will occur

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

modulate enzymes

A
  • change in substrate concentrations
  • change in Km and/or catalytic efficiencies
  • cofactors
  • microenvironments, pH, ion, membrane composition
  • general modulation, positive or negative (ex; ATP, metabolic products, etc)
  • Temperature (Km is temp dependent, Km dec with dec temp, to a point then it inc again)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

isozymes

A

same enzyme, diff structure–> can be altered with temp diff (ex: one active in cold, one active in warm)

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

freeze damage

A
  • primarily due to cell dehydration
  • most animals cannot withstand freexing
  • intracellular ice is lethal
  • most freezing is extracellular but this causes damage due to dehydration of cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

cell dehydration

A

desiccation results in low water inside cell–> call volume dec–> solutes precipitate out–> membranes rupture–> protein denaturing occurs–> protein-protein interaction occurs

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

mechanisms to escape injury due to subzero temps

A
  • behavioral avoidance
  • rapid cold hardening
  • cold acclimatization (avoid ice: inc supercooling ability, for freeze susceptible species; become freeze tolerant)
  • developmental preparedness
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what animals have a problem with freezing

animals that will freeze and animals that won’t

A
  • isosmotic to sea water won’t freeze unless all SW freezes
  • hyperosmotic to FW won’t freeze
  • salt water teleost are hyposmotic to SW-> their FP are above SW-> have a problem with freezing
  • terrestrial organisms encountering subzero temps may freeze
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

marine teleost

freezing

A
  • supercool to -1.9 degrees C
  • OK if don’t come into contact with ice
  • behavioral avoidance: migration to deeper water
  • use antifreeze proteins to depress FP
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Antifreeze proteins

how does it work, what does it produce

A
  • don’t depress FP by colligative means
  • directly binds to ice (adsorbs to ice) and prevents further ice growth
  • produce a thermal hysteresis (a difference between the melting point and freezing point of a solution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Thermal Hysteresis Proteins

A

AFPs = THPs
- coat ice seed crystal
- possess ice binding domain (IBM)
- through adsorption-inhibition, a non-colligative freezing point depressive activity ensues
- can dec FP belowS SW, without inc blood osmolarity
- produced in response to short photoperiod

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

seasonal regulation of AFP

A

growth hormone prevents production of transcription factors necessary to produce antifreeze–> GH not present = antifreeze can be produced (winter)

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

terrestrial environments

A
  • more severe temps
  • need cold acclimatization and other overwintering adaptations
  • 2 strategies: supercooling and freeze tolerant
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

methods to inc supercooling ability

A

1) production of Polyols
2) Antifreeze proteins
3) removal of ice nucleating agents

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

Polyols

A
  • Polyhydroxy alcohols
  • called small MW antifreezes
  • dec FP on colligative basis
  • dec supercooling point on colligative basis
  • inc osmolarity
  • regulated by low temp switching of biosynthetic pathways
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

removal of Ice nucleating agents

A
  • must be done to allow for supercooling
  • ex: emptying gut in anticipation of winter
  • eliminating any nucleating macromolecules
  • masking ice nucleators
  • AFPs may mask INAs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Successful supercooling

A
  • involves all 3 methods to dec SCP
  • polyols
  • AFPs
  • removal or masking of INAs
  • with freeze susceptible species, freezing is lethal-> must remain supercooled in freezing temps
  • supercooling is unstable, duration is a challenge
26
Q

Freeze hardy species

A
  • various invertebrate, especially insect, some lower vertebrates
  • produce cryoprotectants and other chemicals which prevent desiccation
  • In these species, the temp at which they freeze (SCP) is higher than their lower lethal temps
27
Q

freeze tolerant methods

A
  • produce cryoprotectants: Polyols
  • may produce ice nucleating agents
  • may use AFPs to inhibit recrystallization
    0 inc blood bound water
28
Q

cryoprotectants

A
  • small mw cryoprotectants
  • dec water loss by reducing osmotic gradient and inc viscosity
  • helps maintain cell volume
  • acts as solvent like water
  • dec amount of ice at a given time
  • dec osmotic stress
29
Q

Ice nucleating proteins

A
  • like antifreeze proteins
  • some species produce proteins that will nucleate ice at relative high subzero temps–> allows them to control rate of freezing (limits osmotic shock)
30
Q

recrystallization

A

during the melt, the growth of large ice crystals at expense of smaller ones
- slow thaws can cause membrane damage
- large ice crystals can shear membranes
- AFPs can block or limit the extent or recrystalization

31
Q

mechanisms of heat gain

A
  • metabolic heat production
  • conduction (gain or loss)
  • Radiation (gain or loss)
32
Q

conduction

A

transfer of heat between two objects in contact

33
Q

convection

A

transfer of heat to a fluid in movement

34
Q

radiation

A

electromagnetic radiation emitted/recived

35
Q

mechanisms of heat loss

A
  • conduction (gain or loss)
  • radiation (gain or loss)
  • Evaporation (mostly heat loss)–> cutaneous and respiratory
36
Q

to maintain constant body temp…

A

heat gain=heat loss

Metabolic heat+/- heat conduction +/ heat radiation +/- heat evaporation and +/- heat of storage

37
Q

mechanisms of heat control

A
  • metabolic rate
  • insulation
  • vascular control
  • evaporation
  • behavior
38
Q

behavioral mechanisms

A
  • migrations
  • basking
  • aggregation
  • evaporation
39
Q

heat in Aquatic organisms

A
  • no evaporation
  • Coefficient of K is very high for water–> lots of heat loss
  • heat exchange between gills and tissues
  • countercurrent heat exchangers at swim muscles
40
Q

Cardiovascular control for aquatic organisms

A

shunting blood flow through heat exchangers or periphery, inc blood flow through rete mirabile to inc heat loss at higher temps

41
Q

mechanisms of thermogenesis in homewotherms

A
  • inc voluntary activity
  • shivering
  • non-shivering thermogenesis
  • brown adipose tissue -
42
Q

non-shivering thermogenesis

A
  • involves Na+/K+ active transport
  • ATP is used up and excess energy foes to heat–> inc gradients
43
Q

Thyroid hormone

A

turns on Na+/K+ ATPases to generate heat
- also inc MR independently

44
Q

Brown Adipose Tissue (BAT)

A
  • only in mammals
  • sole purpose is for heat production
  • high number of mitochondria
  • high cytochrome–> consumes oxygen at great rate–> heat production (uncouples oxidative phosphorylation)
  • accumulated seasonally and in new borns
  • site of nonshivering thermogenesis
45
Q

Where is BAT found

A

around body organs and upstream from them so the blood flows from BAT to organs

46
Q

neural control of BAT

A
  • epinephrine produced by adrenal meulla
  • works via cAMP
47
Q

purpose of BAT

A
  • uncouples oxidative phosphorylation which produces ATP–> energy goes to heat
  • turns on ATPases
  • cycling of carbon sources and ATP splitting–> heat
  • proton transport system
  • Uncoupling Protein 1 (UCP1) aka thermogenin in inner membranes of medulla
48
Q

adaptations of homeotherms to high temp

A
  • heat dissipation
  • condution (seasonally vary insulation)
  • peripheral vasodilation–> inc heat loss
  • don’t normally dec MR with inc temp but behavioral activity may dec
  • evaporation (respiratory surface)
  • perspiration–> sweat glands in mammals
  • heat storage
49
Q

problem with panting

A
  • causes hyperventilation–> respiratory alkalosis (gives off a lot of CO2, throws of acid base balance
  • involves muscular activity
50
Q

problem with perspiration

A

loss of salts and water

51
Q

temperature sensors

A
  • peripheral sensors
  • core body temp sensors (monitor organs)
  • CNS (temp sensitive regions)
  • Hypothalamus= master control–> itself temp sensitive, receives input from everything else
52
Q

hypothalamus acts like thermostat

A
  • temp set points(when temp goes above these compensation is initiated)
    1) shivering
    2) nonshivering thermogenesis
    3) hormonal *thyroid hormone and epinephriine in BAT)
53
Q

fevers

what is it

A
  • set points are reset to higher temp by proteins called pyrogens (released be leucocytes)
  • temp regulating systems don’t kick in
54
Q

salicylates

A
  • in asprin
  • reset set poin temp back where it should be
55
Q

are fevers functional

A
  • fight disease
  • inc WBC mobilization
  • inc lyphocyte activity
56
Q

behavioral fever in fish

A

bacterically infected fish will choose higher temp in a thermal gradient

57
Q

hibernation and daily torpor

A
  • high energetic cost to maintain constant body temp in cold
  • set points changed from 37C to 2-3C
  • if temp goes near freezing animals will wake up
58
Q

entry into torpor

A
  • T ambient below critical temp
  • dec MR-> dec Tbody
  • inc fat accumulation
59
Q

during hibernation and torpor

A
  • dec heart rate
  • dec MR
  • repiration and ventilation rates are sporadic
  • dec T body
  • dec functions
60
Q

process of arousal

A
  • considerable energy expenditure
  • vital organs warm fastest
  • BAT
  • violent shivering
  • inc T body
61
Q

control of entry into hibernation/daily torpor

A

-photoperiod
- temp
- lack of food
- circannual rhythms

62
Q

duration of hibernation/ daily torpor

A

arrousal at temp 0, requires BAT

Animal Physiology Exam 1 (2 decks)

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