Skin + temp control Flashcards
4 mechanisms involved in thermal balance
Conduction
Convection
Evaporation - 600ml/day
Radiation - accounts for 60% of heat loss
Location of peripheral thermoreceptors
Skin
Location of central thermoreceptors (3)
spinal cord, abdominal organs, hypothalamus
Change in environmental or core body temp is detected by peripheral and central thermoreceptors respectively which input this info to where
hypothalamic therogregulatory centre to produce response to either increase or decrease body temp
Above what temp do proteins denature and below what temp do we lose consciousness
41
30
Responses to cold stress
Generate more heat within body by
- shivering thermogenesis
- voluntary muscular activity
Reduce heat loss by
-vasoconstriction to reduce delivery of blood to skin
Responses to overcome cold stress
Generate more heat within body by
- shivering thermogenesis
- voluntary muscular activity
Reduce heat loss by
-vasoconstriction to reduce delivery of blood to skin
Responses to overcome heat stress
Heat production minimised by
- decreased physical activity
- decreased food intake
Heat loss increased by
- vasodilation to increase blood delivery to skin
- sweating - sympathetic cholinergic fibres increase evaporation
Consequences of heat stress (2)
Heat exhaustion
- body temp between 37.5-40
- results in vasodilation and drop in central blood volume
- disturbance of body’s fluid/salt balance due to excess sweating
Heat stroke
- body temp >40
- temp control mechanisms fail
Fever is caused by what fever inducing substances + describe how fever works
endogenous pyrogens
- they shift the ‘set point’ (i.e. set temp) controlled by the hypothalamus due to local production of prostaglandins by cycle-oxygenase in the hypothalamus
- so the body temp regulates around a higher than normal temp
