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nucelator
Ice crystal formation needs a trigger called a ________________
supercooling
a state where liquids don’t solidify even below their normal freezing point
-40C
Without a nucleator, water can remain liquid until a low of -__C
shrinks
If ice forms outside the cells, the water is drawn out, causing a hypertonic stress that _________ the cell, and may kill it
tolerance
a strategy for surviving freezing temps where animals can allow their tissues to freeze
avoidance
a strategy for surviving freezing temps where animals use behavioral and physiological mechanisms to prevent ice crystal formation
high
Endothermy is intertwined with low/high metabolic rate
more
High metabolic rate causes more/less heat production
regulate
Endothermy requires ability to _____________ temperature
thermogenesis
ability to generate heat
heterothems
exhibit temporal or regional endothermy
temporal
regional
2 types of heterotherms
basking
behavior that accentuates the warming effect of solar energy
huddling
behavioral strategy that reduces SA:V
birds
Shivering is unique to __________ & mammals
shivering
uncoordinated myofiber contraction that results in no gross muscle contraction
short
Shivering works for ________ periods of time
expensive
Shivering is ___________ and muscles are rapidly depelted of nutrients and become exhausted
locomotory
Shivering prevents the animal from using ___________ muscles for foraging or predator avoidance
piloerection
hair & feathers act as insulation and reduce thermal conductivity by standing up using erector muscles
vasomotor response
regulation of the amount of blood flowing into the vasculature
sympathetic
___________ nervous system controls normal body temp and (rapid involuntary responses) maintains tonic constriction of arterioles
adrenergic
Sympathetic nervous system is mediated by _____________ signals
relaxed endothermy
hypometabolic phase accompanied by a decrease in body temp
membranes
water, hypertonic, shinks
2 deleterious effects of ice crystal formation
Points and edges can pierce _________
Ice forming outside of the cells can draw ______ out → ________ stress, _________ the cell (and then may kill the cell)
nucleators
intracellular solutes
2 mechanisms of freeze tolerance
Produce __________ outside of the cell
Produce _______________ ___________ to balance the movement of water
urea, glucose, glycogen, glycerol
What are some examples of intacellular solutes that are used to balance the movement of water in freeze tolerant species?
osmotic
reduce
stabilize
When producing intracellular solutes to balance the movement of water in freeze tolerant species, the solutes
Increase the _________ pressure within the cells which increases/reduces the movement of water and cell shrinkage
AND it helps __________ the macromolecular structure (i.e. fats, proteins)
freeze avoidance
strategy that involves using behavioral and physiological mechanisms to prevent ice crystal formation
solutes
osmolarity
antifreeze
2 mechanisms of freeze-avoidance
Depress the freezing point by adding __________ to the liquid
As ___________ increases, freezing point decreases
______________ proteins which disrupt ice crystal formation by binding to small ice crystals and preventing growth
antifreeze
proteins that disrupt ice crystal formation by binding to small ice crystals and preventing growth
heterothermy
exhibiting temporal or regionally different body temps
temporal
heterothermy that changes over time
hibernating/torpor, fever response, sleep
examples of temporal heterothermy
regional heterothermy
priority on maintaining certain anatomical regions within very narrow thermal ranges
CNS and internal organs at a more constant temp, while allowing periphery to vary
birds in polar areas may allow their legs and feet to reach much lower temps than their body which is maintained at core temp
example of regional heterothermy
TNZ
in the ____ MR does not need to change to keep body temp constant
insulation
Having more ____________ means that the MR does not have to change as much to keep the animal at a constant temperature, having less means that the body is more susceptible to changes in ambient temp, and thus the MR must change more to account for these changes
basking
huddling
name 2 strategies displayed by animals experiencing cold
thermogenesis
creating heat
shivering thermogenesis
uncoordinated myofiber contraction that results in no gross muscle contraction
short
depleted
locomotry
shivering thermogenesis
works for ________ periods of time — muscles are rapidly ________ of nutrients and become exhausted
prevents the animal from using _____________ muscle for foraging or predator avoidance
brown adipose tissue
non-shivering thermogenesis uses what?
non-shivering thermogenesis (BAT)
important in thermogenesis for small mammals and newborns that live in cold environments
back & shoulder region
Where is BAT located?
adipocytes
mitochondria
thermogenin
BAT is different from white ___________ in that
it has higher levels of ___________
it produces the protein ____________
thermogenin
uncoupling protein that increases mitochondrial activity and uncouples the mitochondrial electron transport system and proton pumping from ATP synthesis
thyroid
In rodents, _________ hormones stimulate BAT thermogenesis
vasomotor response
regulation of the amount of blood flowing into the vasculature
hypothalamus
What controls the vasomotor response?
decrease
tonic
dilate
rabbit
Example of vasomotor response
When body temp is high there is a increase/decrease in _____ constriction of the arteriole and the vessels __________ to allow more blood flow
ex: blood flow increases to _______ ears when it’s hot in order to cool down
local
tissues
Vasomotor response
_______ control of blood flow can control the rate of heat loss in high surface area _______________
countercurrent system
arrangement of 2 flowing parallel systems so that their directions fo flow are opposite of one another
countercurrent system
most effective and simple way of insuring efficient exchange between the two flows (may exchange water, ions, gases, heat)
hairpin
turn
top
longer
A countercurrent system creates a thermal gradient along a ____________ loop.
it’s coolest at the ____ and warmest near the ____ of the hairpin
The ________ the loop the greater the gradient
relaxed endothermy
hypometabolic phase accompanied by a decrease in body temperature
hibernation torpor
examples of relaxed endothermy
saved
In relaxed endothermy, metabolic energy that would normally be used for thermoregulation is _______
specialized nose
dry feces
posture changes
high tolerance for dehydration
some of the ways that camels cope with high heat
fat
What do camels’ humps store?
cycle
evaporating
gain
When dehydrated, camels let their body temp _______
Instead of _________ to cool down, they store their heat and let their body temp cycle with ambient temp
increasing their body temp reduces the amount of heat ____ from the environment
warm receptors
the things that increase firing when hypothalamic temp rises above a certain setpoint
cold receptors
things that trigger heat production when the hypothalamic temp falls below a specific setpoint
peripheral
thermoreceptors that are secondry to the core receptors and brain regulation center