15.3 Thermoregulation in Endotherms Flashcards
What is an endotherm?
animals which rely on METABOLIC PROCESSES
to WARM bodies & maintain core body temperature.
What is the name of the type of receptor which detects changes in temperature?
thermoreceptor
What are the 2 main types of thermoreceptor?
peripheral
hypothalamus
What is the role of peripheral thermoreceptors?
detect changes in SURFACE TEMPERATURE
send information to THERMOREGULATORY CENTRE
Where are peripheral thermoreceptors located?
skin surface
What is the role of the thermoreceptors in the hypothalamus?
detect changes in temperature of the BLOOD deep in body (indicator of CORE body temperature)
send information to THERMOREGULATORY CENTRE
Why do peripheral thermoreceptors detect a change in temperature before hypothalamus thermoreceptors?
peripheral thermoreceptors are in skins surface
skins surface is more exposed
affected by temperature change before core body
∴ peripheral thermoreceptors respond before
What are the responses during thermoregulation which DECREASE core body temperature?
VASODILATION
INCREASED SWEATING
LOWER HAIRS
What are the responses during thermoregulation which INCREASE core body temperature?
VASOCONSTRICTION
DECREASED/NO SWEATING
ERECT HAIRS
SHIVERING
What occurs during VASODILATION?
- ARTERIOLES supplying capillaries close to surface of skin DILATE, + ARTERIOVENOUS SHUNT vessels CONSTRICT
- MORE blood forced through capillaries
- greater heat loss from RADIATION
How does SWEATING decrease core body temperature?
- sweat GLANDS secrete sweat onto skins surface
- sweat evaporates, taking heat energy from body
- greater heat loss from body
How does LOWERING HAIRS decrease core body temperature?
- ERECTOR PILI MUSCLES RELAX
- Hair/feathers lie FLAT on skin
- Avoids trapping INSULATING LAYER of air
- less heat retained
What occurs during VASOCONSTRICTION?
- ARTERIOLES supplying capillaries close to surface of skin CONSTRICT, + ARTERIOVENOUS SHUNT vessels DILATE
- LESS blood travels through capillaries
- less heat lost from blood by RADIATION
How does RAISING HAIRS increase core body temperature?
- ERECTOR PILI MUSCLES CONTRACT
- Hair/feathers stand up on skin
- traps INSULATING LAYER of air
- more heat retained (heat concentration gradient less steep)
How does SHIVERING increase core body temperature?
involuntary CONTRACTING + RELAXING of voluntary muscles
rate of aerobic RESPIRATION ￪,
EXOTHERMIC reactions warm body
