Define the term homeotherm.
species that maintain constant body core temperature ie humans and animals
uses furnace to maintain body temp
Present an overview of heat balance during exercise.
exercise using large muscle groups can result in large amounts of heat production. beasuce the body is at most 20 to 30 % efficient 70 to 80 % of the energy expended during exercise is release as heat
amount of heat lost must equal the amount of heat gained
Discuss the concept of “core temperature.”
core temp the regulator within the body
List the principal means of involuntarily increasing heat production.
exercise using large muscle groups can result in large amounts of heat production. beasuce the body is at most 20 to 30 % efficient 70 to 80 % of the energy expended during exercise is release as heat
shivering
custaneous vasocontriction
catecholamine release
thryoxine release
Define the four processes by which the body can lose heat during exercise.
body heat can be lost through evaporation, convection, conduction, radiation. during exercise in a cool environment, evaporation is the primary avenue for heat loss
evaporation is dependent upon 3 factors
1) air temp and relative humidity
2) convective current around the body
3) amount of skin exposed to the enovinrment
Discuss the role of the preoptic-anterior hypothalamus as the body’s thermostat.
temperature control area
when cold stimulate
- shivering
- vascoconstriction of exterior limbs
catecholamine release
thyroxin release
when hot stimulus
- sweating
- vasodilation of exterior limbs
Explain the thermal events that occur during exercise in both a cool/moderate and hot/humid environment.
exercise in a hot evoinrment
- increase sweating
- increase core temp
hot environment
- see graph
- central nervous dysfunction
cardiovascular dysfunction
accertate muscle fatigue
List the physiological adaptations that occur during acclimatization to heat.
increased plasma volume
earlier onset of sweating
higher sweat rate
reduced salt in sweat
reduced skin blood flow
increased synthesis of heat shock protein
Describe the physiological responses to a cold environment.
decrease in skin blood flow
Discuss the physiological changes that occur in response to cold acclimatization.
1) decrease mean skin temperature at which shivering begins –> due to increase NE
2) maintain higher mean hand to foot temp –> increase vasodilation to hands and feet
3) ability to sleep in cold
acclimation
acclimatization
conduction
convection
evaporation
homeotherms
species that maintain a constant core body temp ie humans and animals
hyperthermia
hypothermia
preoptic-anterior hypothalamus
radiation
specific heat
thermoreceptors
Define the following terms: (1) homeotherm, (2) hyperthermia, and (3) hypothermia.
hyper - hot
hypo - cold
Why does a significant increase in core temperature represent a threat to life?
