Skin and temperature regulation Flashcards
What is core body temp?
37 +/- 0.5
What happens to the body above 41?
Proteins syart to denature
What happens to the body below 30?
Lose conciousness
What does body temp vary with?
External temp
Activity
Circardian rhythm
Menstrual cycle
What factors are important in thermal balance?
Convection
Conduction
Evapoation
Radiation
What is conduction?
Heat transfer between directly touching objects
How do we lose heat via evaporation?
Respiartion
Sweating
How much heat loss if via radiation?
60%
How is the body’s temp detected?
Peripheral thermoreceptors
Central thermoreceptors
Where are peripheral thermoreceptors located?
Skin, esp face and scrotum
Where are central thermoreceptors located?
Spinal cord, abdo organs and hypothalamus
Where is information from the peripheral and central thermoreceptors sent to?
Hypothalamus
How us heat generated within the body increases?
General metabolism
Voluntary muscular activity
Shivering thermogenesis
Non shivering thermogenesis in infants
How is heat loss from the body reduced?
Vasomotor control- Sympathetic arteriolar constriction reducing blood supply to skin
Behavioural responses- reducing surface area, adding clothing, going somewhere warmer
What is hypothermia?
Fall in deep body temp below 35
Who is at risk of hypothermia?
Neonates Elderly Vagrants- homeless person Cold store workers Outdoor pursuits North sea workers
Why are neonates at risk of hypothermia?
Not much fat, don’t shiver well
Why are the elderly at risk of hypothermia?
Don’t detect temp change well
Less shivering capacity, less mobile
What is the treatment of hypothermia?
Dry/insulate to prevent further heat loss
Slow rewarmingInternal rewarming with hot drinks and/or warm air
Fast rewarming by water immersion
What are the types of frost bite?
Vascular
Cellular
What causes vascular frostbite?
Vasoconstriction
Increase in viscosity
Promotes thrombosis
Causes anoxia
What causes cellular hypothermia?
Ice crystals form in extracellular space, increasing extracellular osmolarity, causing movement of water from intracellular space
Dehydration and death
How does the body minimise heat production?
Decreased physical activity
Decreased food intake
How does the body increase heat loss?
Vasomotor control- arteriolar dilation
Sweating
Behavioural responses- increase surface area, remove clothing, move to shaded area
What is heat exhaustion?
Body temp 37.5-40 resulting in vasodilation and drop in central blood volume
What causes heat exhaustion?
Disturbance of body’s fluid/salt balance due to excessive sweating
What are th symptoms of heat exhaustion?
HEadache Nausea Confusion Profuse sweating and clammy skin Tachycardia Hypotension Weak pulse Fainting and collapse
What is heat stroke?
Body temp >40 due to body temp control mechanisms failing
Wha are the symptoms of heat stroke?
hOt dry skin
Circulatory collapse
Who is most at risk o heat exhaustion and stroke?
Neonates and elderly
People doing physical work in hot, humid environment
Workers in non breathable protective clothing
What is the treatment of heat exhaustion and stroke?
Move to cool environment Remove clothing Fan Sponge with tepid water Give fluids, oral or IV
What is a fever?
Part of body’s mechanism for fighting infection
What causes a fever?
Endogenous pyrogens shifting the set point
