Physiology wk8 Flashcards
what is a homeotherm
refers to humans, as we keep our body temp at around 36-37
what are the max and min values humans can change their temp to
lowest = 35
highest = 40
what is the core temp measured by
thsi is the temp of the hypothalamus measured by
* Oesophageal temperature
* Rectal temperature
* Stomach temperature
* Oral temperature
* Tympanic temperature
how does shell (skin) temp vary
cool, warm, hot
30
30-34.9
35+
how does temp regulation work
peripheral/central thermoreceptors -> hypothalamus -> messages to:
adrenal medulla
sweat glands
skin arterioles
skeletal muscles
to reduce temp
what is the formula for heat storage
metabolic heat prod + convective heat loss + conductive heat loss +- radiant heat loss - evaporative heat loss
S= m ± Cv ± Cd ± r – e
what is diff between core and skin temp regulation
different areas in core always gona be the same, skin varies in different areas upon the external environment
what are the different thermoregulatory responses, cooling down and heating up
- Skin blood flow increased
- More sweating
- More shivering
why is aerobic performance impaired in hot and humid environments
- Increased demand on heat loss mechanisms
- Reduced gradient between core and skin
less blood flow to active muscles more to skin, loss of ability to produce muscular force
what is dehydration
loss of fluid from the body beyond regular levels
what does dehydration casue
- Exacerbates heat stress impacts
- Decreases sweat rate and plasma volume
- Further reduces cardiac output, maximal oxygen uptake, muscle strength and work capacity
what is hypothermia
when core body temps drop 2-6c, heat loss > heat production
2c – maximal shivering
4c – ataxia and apathy
6c – unconsciousness
what are the adaptions made to the cold
- lower skin temp that shivering begins
- improved peripheral blood flow
- improved ability to sleep in the cold
how does low air density effect anaerobic performance
offers less resistance to high-speed movement, and sprint performances are either not affected or are improved
how does low density effect jumping
- Short-term anaerobic performance effects:
lower air resistance may improve performance - Lower PO2 at altitude should have no effect on performance (O2 transport to muscle doesn’t limit performance)
how does low air density effect aerobic performance
makes it harder, less pO2
what is boyles law
gas volume inversely proportional to its pressure
what occurs to air at high altitude
there is the same % of gas within the air but less partial pressure. Additionally atmospheric pressure is lower at higher altitudes
same split of n/o2 but lower partial pressure
what is hypoxia
low po2
what us normoxia
normal po2
what is hypoxaemia
low levels of o2 in blood
what happens during hypoxia
reduction in arterial oxygen pressure (PaO2), this triggers neuroendocrine responses to help regulate adjustments in the physiological system.
what are the adjustments to altitude
Ventilation changes:
* hyperventilation
* Raises alveolar O2
* Lowes alveolar CO2
* Causes alkalosis and diuresis (HCO-3)
Cardiovascular changes
* Increased resting HR and Q
what happens to ventilation at higher altitude
increased ventilation for same wr
