Quiz 1 Flashcards
Being a homeotherm can aid survival, but it can also lead to death. How?
If heat gain is greater than heat loss.
As a homeotherm, there is a gradient of ??? between the core temperature and the skin temperature?
5.6 degrees F
Heat can be removed from the core when it is picked up by
Blood
Humans are homeotherms which means..
We can dictate our own body temperature and regulate internal temperature through metabolic activity
Every minute we give off heat. If we couldn’t, what would happen?
Our core temperature would go so high that it would kill us
What is our core temperature?
98.6 degrees F
What is our skin temperature?
93 degrees F
How can being a homeotherm be life saving?
We can adapt to different environments and temperatures
How can being a homeotherm be life threatening?
If the gradient is affected, the heat will become trapped in our core which can result in death. Or in cold conditions, the body temperature may become too cold and drop too low, resulting in death.
At rest, what happens to all metabolic activity?
It ends up as heat
As you do work, what happens to all metabolic activity?
Not all of it goes to heat because you need some of the energy in order to do the work
Why would your body rather have fat than muscle?
Because your body is dependent on energy and fat stores energy. Muscle takes a lot of energy
What is the most important element in the body?
Water!
What are the 4 processes for losing heat?
Convection, Conduction, Radiation, and Evaporation (sweating)
What is convection?
Movement of air currents over skin
What is conduction?
Direct contact. Transfer of heat to skin through direct contact
What is radiation?
Most of the heat lost comes from radiaton.
Does your body want to sweat? Why or why not?
No because it is losing water and sweating does not really cool the skin or reduce heat level
Will you evaporate sweat in 100% humidity?
No
Will you evaporate sweat in 10% humidity?
Yes. This can be dangerous because it can mislead you into thinking you are not sweating when in reality you are rapidly. Can lead to dehydration
If the temperature gradient is unfavorable what happenss?
The heat gets trapped into the core and will not be able to leave the skin.
Example of unfavorable gradient?
Being stuck in an elevator with 10 people. They will be radiating heat towards you
1 pint of water lost = ??
1 pound lost
a negative helps you —- heat
lose
+ helps you —– heat
gain
What does insensible mean?
Not aware of it. Restrictive to respiratory tract.
What controls heat loss?
Anterior hypothalamus
What controls heat gain?
Posterior hypothalamus
What is the first heat loss mechanism that occurs?
Vasodilation
What is the second heat loss mechanism?
Evaporation of sweat
Why does the body want to avoid sweating?
Because it does not want to lose water
If blood flow is sluggish, why is that good?
It allows for more time to lose heat
Large stroke volume means?
Heart does not have to beat as often
Small stroke volume means?
Heart has to beat more often
What is the first physiological response when exposed to cold?
Vasoconstriction
What triggers vasoconstriction?
Posterior hypothalamus
What is the second physiological response when exposed to cold?
Non-shivering thermogenesis
Non-shivering thermogenesis releases what hormones?
Norepinephrine and thyroxine
What is the third physiological response when exposed to cold?
Shivering
Why does the body not want to shiver?
Because it is wasted muscle contractions that requires energy and removes heat from the body
The process of acclimatization is how long?
10-12 days
What is the first thing that happens with acclimatization?
Increased plasma volume in the blood stream
Why is increased plasma volume helpful?
Get blood to the skin and the working muscles by vasodilation