Thermoregulation Flashcards
how can heat be exchanged ?
- radiation
- conduction
- convection
- evaporation
heat conservation mechanisms
shivering thermogenesis
voluntary muscle activity
non-shivering thermogenesis
heat loss mechanisms
blood reaching the skin
sweating
when BT increases how does the body return it to normal?
Thermosensors detect the change in temperature send signals to the central command which causes blood vessels to dilate, sweat glands to secrete fluid and heat is lost to the environment returning BT to normal
why does vasodilation occur in blood vessels in the skin?
due to a reduction of sympathetic stimulation
and due to the release of acetylcholine from specialised sympathetic neurons
what causes vasoconstriction?
norepinephrine acting on alpha adrenergic receptors
what neurons stimulate shivering ?
shivering is the result of stimulation by somatic motor neurons
heat conserving mechanisms
increase shivering
decrease skin blood flow to the periphery
behavioural eg. clothing
heat loss mechanisms
increase sweating
increase skin blood flow to periphery
behavioural eg. less clothing
what is hypothermia ?
core body temperature becomes dangerously low
what is hyperthermia?
core body temp becomes dangerously high 40.5 degrees
what are the signs of heatstroke?
dizziness
disorientation
skin appears dry
HR elevated
collapse
how do athletes cope with heat during exercise in hot environments?
acclimation- repeated exposure to heat either by habituation in a hot climate or use of environmental chambers
acclimatisation begins after 5-10 days of prolonged exercise in the heat
what physiological changes occur during acclimatisation?
- sweating more and sooner
- increasing blood flow to skin
- have more dilute sweat
- increase blood and stroke volume
- have a lower body core temp, HR, glycogen use and thus fatigue
