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
Why is sweating sooner helpful?
your body will store less heat prior to initiation sweating. this allows you to prevent your body temp from getting too high first, which can cool the body
What is a recent discovery that is believed to be protective of the heart muscle?
Shock proteins
The most serious heat injury is?
Heat stroke
Heat stroke begins with the loss of fluid from?
extracellular space
During a heat stroke, the outside of the cell becomes?
Hypertonic
During a heat stroke, the inside of the cell becomes?
Hypotonic
What is messed up when the inside becomes hypotonic and outside becomes hypertonic?
The osmotic balance
When the osmotic balance is messed up, fluid moves from — to —
intracellular space to interstitual fluid ???
During heat stroke, the body looks for another fluid source to serve as sweat and it finds it where?
In the blood
Sophie’s choice can either…
- keep ruining the cells in the body or 2. sweat plasma
After Sophie’s choice decision, the body decides to ?
stop sweating, which could cause heat stroke
The wet bulb globe temperature takes what into account?
air temperature, radiant effect of heat from sun, and humidity
What is VO2 max and what does it measure?
Maximal aerobic capacity. it measures oxygen consumption
What factor mostly influences evaporation?
Humidity
What is the specific heat of human tissue?
0.83
It takes us —- C of energy to do —- C or work
5, 1
Human body at work is how efficient?
20%
If we were 100% efficient, what would happen
we would be like reptiles. we would also have to eat a lot less calories
The specific heat of water is?
1
How is specific heat of water determined?
the number of kcals required to raise 1 kg of water 1 degree C
The kcal equivalent table is used to determine…
how many kcal of heat are produced per liter of oxygen consumed
what 3 gases do we inhale?
oxygen, nitrogen, and carbon dioxide
what is it called when we want oxygen coming in and carbon dioxide going out?
gas exchange
what is the main goal of breathing?
to get oxygen down into the depths of the lungs, which is the alveoli where it can find its way into the blood stream
capillaries are what?
the smallest blood vessel
what is the main goal of the cardiovascular system?
get blood into the capillaries
second goal of cardiovascular system is what?
build up the partial pressure of oxygen (PO2) because we want pressure behind the oxygen to push oxygen into the bloodstream
What does hemoglobin consist of?
4 sites where they can carry 4 oxygen molecules
why does the hemoglobin need to move rapidly?
because if they don’t, then the RBC will pass by and wont be time to pick up the oxygen molecules
what is the partial pressure of oxygen?
20.93%
what is the partial pressure of carbon dioxide?
.04%
what is the partial pressure of nitrogen?
78%
total air pressure is typically what?
760 mmHg
as you go up in altitude, what happens to the size of gas molecules?
the size stays the same but the space it occupies changes
what happens as you go up in altitude?
the pressure decreases, the movement increases, and the gas molecules occupy more space
the ultimate purpose of breathing is to increase the
partial pressure of oxygen in the alveoli in order to facilitate diffusion where they combine with hemoglobin
goal of the pulmonary system?
load of every site of hemoglobin
what is the first effect of altitude?
deeper faster breaths
what is the hormone that is released after longer exposure to altitude
EPO
what does EPO do?
stimulates more RBC production
where does EPO come from?
kidneys
RBC production was mimicked by
blood boosting
blood boosting is also called
blood doping
If your efficiency is high, your energy will be —??
high
where does oxygen exchange occur?
in the capillaries
when oxygen combines with hemoglobin what happens?
the bond is tight and oxygen does not move form hemoglobin easily
if there is a lower concentration where i am going, what happens to the oxygen and hemoglobin bond?
it weakens and as the PO2 of oxygen gets lower, it dissociates easily and the bond is given up easier so the oxygen moves more easily into the working muscles
what happens to % saturation as you go up in altitude?
it gets lower and lower
the random movement of microscopic particles suspended in a gas, caused by collision with other molecules is called??
brownian movement
Charles law says what?
at constant pressure, temperature increases, and volume increases
Boyles law says what?
at constant temperature, pressure increases, and volume decreases
what happens to the % of gas as you go up in altitude?
the percentage does not change! the partial pressure changes.
the urge of wanting to come up from being underwater is due to the buildup of??
carbon dioxide
when a scuba diver comes up too quickly the —- forms —-
nitrogen, bubbles
nitrogen forming bubbles can cause tissue and nerve damage. this is called —–
decompression illness
decompression illness is also called ??
bends
what happens in a decompression chamber?
they compress it and take it back down to the pressure that they were at under sea level then they gradually reduce the pressure and bring the nitrogen out of the body.
when oxygen is increased in the alveoli to facilitate movement, this is known as what?
diffusion
VO2 max decreases at high altitude because of decrease in —-
oxygen
for evert unit of volume of blood that is delivered to working muscles there are —-
less oxygen molecules
when there is less oxygen molecules the heart has to —
pump blood faster and harder
when the blood is pumped faster and harder, what happens
you reach a max heart rate sooner and reducing VO2 max
at high altitude, how might the cost of breathing interfere with an endurance performance?
when breathing, you take in less oxygen at high altitude so the PO2 iin the alveoli will be lower, decreasing the rate of diffusion in the bloodstream which leads to less oxygen in the muscles
the peak of oxyhemoglobin association curve reflects what is occurring where? what is PO2?
blood picks up oxygen from alveoli, PO2 of 150 mmHg
the oxyhemoglobin dissociation curve reflects what if happening where? and what happens to oxygen and hemoglobin bond?
oxygen is being dropped off to the muscles and the PO2 drops and oxygen/hemoglobin binding strength is weakened
