extreme biology Flashcards
temperatures, human pressures, physiological pressures
what is thermoregulation?
body aims to maintain internal core temperature of 36.6 - 37.1 degrees
hypothalamus role in maintaining homeostasis for core temperature?
1) thermal receptors in the skin provide signals to hypothalamus about the surface temperature of the body, if too hot, causes vasodilation= result in heat loss by radiation or sweat loss
2) Temperature changes in the blood, too cold, cause vasoconstriction = less heat loss by radiation to keep warmth in core and protect organs
temperatures range for athletes performance
> 32 degress- reconsider event
40 degrees- risk of dying
11 degress- optimal performance
5%- not as good as 11 degrees but better than the higher ones
strategies to cope with exercising in the heat
heat acclimatisation-
exposure to temperatures 10 days before a race to improve heat tolerance.
active- 5x 60-90 minutes exposure a day
long term- 10x 60-90 minutes exposure a day
goal= reduce core temperature exercising in heat and increase rate of heat loss (sweat rate)
how the cold effects us during exercising?
1) max power output in muscles drops around 3% per degree reduction in muscle temperature
2) v02 max is reduced by 10-20% if core temperature falls by 0.5- 2 degree. stride length is decreased leading to slipsnd falls.
the effects of pressure on the human body?
1) total pressure
2) duration of exposure to pressure
3) state of activity- depends on oxygen demand and red blood cell formation
4)temperature
5)drugs in body- alters tolerance
6) gas mixtures- oxygen and nitrogen
7) rate of ascent and descent
(has worst affect)
effects of extreme high pressure and different laws
Boyles law- as pressure increases the volume of gas decreases. as. diver descends pressures increases by ‘1 ATM’ for every 10 metres of depth.
leads to compression of air in divers lungs
Henrys Law- increasing pressure increases the amount of gas that will dissolve. eg nitrogen dissolving in blood stream when scuba diving.
Martini Law- effect pf nitrogen narcosis
10metres- 1 martini
40m - 4 martinis (the limit)
definition of partial pressure
pressure exerted by an individual gas molecule in a mixture
how ‘the bends’ (decompression sickness) occurs and result?
- diver ascends to quickly
- dissolved nitrogen bubbles in body
- joint pain/ paralysis
what in our bodies identifies low pressure oxygen and c02? >5500 metres
carotid body chemoreceptors -
lead to increased respiratory rate and urination
how long it takes to acclimatise to low pressures and what our body does in response to low pressures?
-takes over a month
-EPO (Erythropoietin) stimulates bone marrow to make more red blood cells which produces more haemoglobin
what happens to your body in the death zone >8000 metres?
1) oxygen is used up faster
2) rapid deterioration of body
3) extreme hypoxia
physical health challenges that can occur due to low pressures?
1) acute mountain sickness (AMS)
2) high altitude pulmonary oedema (HAPE)
3) high altitude cerebral oedema (HACE)
define psychological stress and the terms anxiety, stress, arousal?
psychological- excessive/ stressful demands
anxiety- feelings of tension/worry/fear
stress- bodies response to demands/ challenges
arousal- state of being alert/ readiness
selyes adaption syndrome- three phases of our handling of stress
1) alarm= fight or flight
2) resistance= bodies reaction to stress
3) exhaustion= resources are depleted
