Temperature Regulation Flashcards
What temperature is classed as hypothermia?
Below or equal to 35 degrees C
What temperature is classed as hyperthermic?
Greater than 38 degrees C
What are the effects of hypothermia? 35/33/31/28/26
35-severe shivering, peripheral circulation shut down
33-confusion, drowsiness, coagulation impairment
31-unconscious, risk of arrhythmia
28-respiratory muscle failure
26-death
What are the effects of hyperthermia? 39/40/41/42/43
39-severe sweating and vasodilation and breathlessness
40-vomiting, dehydration, weakness and dizziness
41-faint, confusion and drowsiness
42-brain protein denaturing
43-death
What are cold thermoreceptors?
Peripheral in skin, conducted via myelinated A fibres
What are warm thermoreceptors?
Central in hypothalamus, a few peripherally in skin
What are the response mechanisms to temperature change?
Behavioural (voluntary to change movement and immediate environment) and physiological (involuntary efforts that influence the rate of heat production and rate of heat loss)
What are the main physiological effector systems?
Neurological (symp-vasomotor tone and sweating, and motor system-controlled activity, shivering) and hormonal (thyroid-thyroxine and adrenal medulla-adrenaline, both to increase cellular metabolism)
Why are neonates high risk for hypothermia?
High body surface area to weight ratio and unable to make behavioural changes
Why do neonates have brown fat between scapulae?
Specialised heat source
Why are people near-drowning at risk of hypothermia?
Huge increase in heat loss by conduction
Why are people who are overdosing on drugs susceptible to hypothermia?
Reduced metabolism and heat production and unable to make behavioural changes
Why are people suffering from major trauma likely to get hypothermia?
Exposure increases heat loss and replacement of blood loss with cold fluid
Why would we want to induce hypothermia?
To reduce metabolic requirements e.g. during brain or heart surgery or following a brain injury
How would we achieve induced hypothermia?
Surface cooling or cardio-pulmonary bypass
