ENERGY 2 Flashcards
what’s thyroxine
the metabolic hormone that is the most important factor in determining BMR
what cells does thryozne not impact
bran
how does thyroxine increase O2 consumption and heat production
by accelerating the use of ATP to operate the Na-K pump
whats thermoregulation
Ability to maintain core body temperature in homeostasis
what is body heat generated by at rest
liver, heart, brain, kidneys, endocrine organs
what is body heat generated by during movement
skeletal muscle
whats radiation
the loss of heat in the form of infrared waves (50% of heat loss)
whats conduction
transfer of heat between two objects in direct contact
whats convection
warm air expands and rises and cool air falls
whats convection enhanced by
warm air
whats evaporation
water molecules absorb heat → turns to gas
how much of evaporation is insensible heat loss
around 10%
what does the hypothalamus receive input from for body temp regulation
Central thermoreceptors (core)
Peripheral thermoreceptors (skin)
which is more influential
central thermoreceptors (core)
which is used to anticipate changes needed
peripheral thermoreceptors (skin)
what does the hypothalamus initiate
heat-loss or heat-promoting activities
what are four heat promoting mechanisms
Cutaneous blood vessel constriction
Shivering
Increased metabolic rate (NE/E release)
⁎ Mainly in infants
Thyroxine release
⁎ Only in infants
what are two heat loss mechanisms
Cutaneous blood vessel dilation
Enhanced sweating
does enhanced sweating work in high humidity
no
is exercising with or without a shirt better in a dry environment
in a dry environment, shirt is better for cool down bc better evaporation etc
whats hyperthermia
Elevated body temp above 105°F (~41°C)
Heat-control mechanisms are not effective
what is considered controlled hyperthermia
fever
whats heat stroke
extended form of heat exhaustion; the body has given up and organ damage is possible
whats heat exhaustion
Heat exhaustion: dehydrated state, precursor to heat stroke
whats hypothermia
Lowered body temperatures
Shivering stops at 87 – 90°F (30 – 32°C)
what happens below 70 C / 21 F
coma / death