thermoregulation Flashcards
normal homeothermy is a balance of what?
- hypothermia
- hyperthermia
2 general classifications of thermoregulation
- poililotherms
- homeotherms
what are poikilotherms?
- ectothermic
- cold-blooded
- variable body temp
what are homeotherms?
- endothermic
- warm-blooded
- “constant” body temp
what are the advantages of poikilotherms?
- less energy expenditure
- food conserving mechanism
- alter behavior based on external temp
what are the disadvantages of poikilotherms?
- unable to have high year-round productivity**
- habitat limitations
- cannot tolerate extremes in temperature
are homeotherms or poikilotherms more capable of tolerating environmental extremes?
homeotherms
are neonates good at maintaining a constant temperature?
no
heat production has to equal=
heat loss
do we lose more animals due to heat stress or cold stress?
heat stress
radiation, conduction and convection are dependent on:
temperature gradient
delta Tc should be close to/equal to what
zero
what is raditaion?
transfer of heat between NON-TOUCHING objects can be a loss or a gain
what is conduction?
transfer of heat between TOUCHING objects can be a gain or loss
what are the two biggest avenues of heat exchange?
- convection
- evaporation
what is convection?
transfer of heat via a FLUID medium
-i.e air, blood, water
what is the most common way we transfer heat?
through the blood
what are the 2 types of convection?
natural and forced
what is natural convection?
warmed air move away from the body occurs in still air situations
what is forced convection?
moving air or fluid over surface
always beware of what?
drafts
what is a great insulator?
air
what are great conductors?
water and blood
what is evaporation?
transfer of heat as a liquid is converted to a gas
what is evaporation highly influenced by?
relative humidity
T/F: evaporation is always a loss.
true
you have to live in an environment above what?
rectal temp
what type of heat transfers heat to the lung surface?
convection
what is vital to survive in heat stress?
evaporation
if you block evaporation, you must increase _______ or decrease ____.
- other losses
- heat gain
aprocine sweat gland have what kind of secretions?
protein
eccrine sweat glands have what kind of secretions?
aqueous
homeotherms must make (more/less) heat production.
more
heat production is proportionate to what?
metabolic size
heat loss is in proportion to what?
surface area
exercise increases what?
basal metabolic rate
hormone of metabolic rate
thyroxine, testosterone
do younger or older animals have a higher BMR?
younger
the is Bergmann’s Rule
in colder climates, animals will be larger
characteristics of hiberation
- reduced metabolic rate ~25% of normal
- lower body temp
- reduced HR
ways to increase heat production:
- shivering
- digestion
- non-shivering thermogenesis
- brown fat
- exercise
to lose heat, we must get it where?
to the surface
are tissues/air good conductors?
no
what is vital to control of hyperthermia?
blood brain temperature
what increases heat capacity?
hydration
Mount;s concept of thermalnutrality
- there’s a wide range of temperature (*balance)
1. comfortability
2. choice
3. max health
4. lowest mainentance
5. max gain and feed efficiency
