IB SEHS SL
Option A.2 Quiz
Name _______________________________________
1.
Date __________
State the normal physiological range for core body temperature. [1]
37oC +1 or + .06 or 98oF (97o F to 100oF)
2.
Outline how the body thermo-regulates in hot and cold environments. [4]
Body heat is transferred by conduction, convection, radiation and
evaporation.
Conduction – Skin contact with something that is hotter or colder;
Passing on heat/cold from one object to the other. If the body comes
into contact with something colder (ice, ice pack, snow), it will lose
temperature. When the body comes into contact with something hotter
(electric blanket, hot road, warm water), it will gain temperature.
Convection – surrounding air/water influences body temperature. If the
air is cooler the body will cool down (air conditioner); can be dangerous if
the wind is too strong (wind chill). If the air is warmer than the body, the
body will gain heat.
Radiation – gain or loss of heat depending on the atmosphere…all
things/beings give off heat (radiate heat) – if the air is warmer than the
body, the body will increase in temperature, and if the air is cooler than
the body, the body will lose temperature. At rest, radiation is the main
source of heat loss.
Evaporation - most important for heat loss; when sweat is
released/evaporated, the body cools down. During exercise, evaporation
is the main means of heat loss.
3.
Explain the relationship between cellular metabolism and the production
of heat in the human body. [4]
Cellular metabolism is used to sum up all chemical reactions taking place
in the body. The body uses glucose from the foods we eat to make
energy rich ATP, which is used to do cellular work. This cellular work is
then converted to mechanical work (movement of the muscles/muscle
contraction). Energy released means there is an increase in body
temperature.
or
ATP is created through cellular respiration, which typically uses O2 to
convert glucose into CO2 and H20.
or
Food (Glucose) + O2 + ADP è ATP + H2O + CO2 + Heat (entrophy)
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IB SEHS SL
Option A.2 Quiz
or
The energy liberated (released) from dietary nutrients through reactions
occurring in metabolism results in both heat production and the
conservation of energy within the compound ATP.
4.
Discuss two physiological responses that occur during prolonged exercise
in the heat. [2]
● Elevated heart rate (O2 uptake increases) to compensate for stroke
volume decrease (cardiovascular drift)
● Body temperature increases
● Increased vasodilation to aid in heat release
● Sweating increases which causes a decrease in blood volume and a
loss of minerals and electrolytes
● Muscle glycogen is being used/depleted, thus increasing lactic acid
build up, which slows the body down – fatigue sets in sooner.
● Active muscles and skin compete for blood supply
5.
Discuss two physiological responses to exercise in the cold. [2]
● Vasoconstriction to keep heat in, which makes it more difficult to
move/exercise. Vasoconstriction in the skin also causes frostbite.
● Muscles weaken and fatigue occurs more rapidly
● The body can lose it’s ability to regulate body temperature, thus,
the risk cold-related conditions increases
● Heart rate drops, which reduces cardiac output
6.
Discuss two health risks associated with exercising in the heat. [2]
Heat cramps – loss of water and sodium; painful muscle cramps
Heat exhaustion – extreme fatigue due to prolonged heat/sun exposure,
dehydration; the precursor to heat stroke.
Heat stroke – the body is no longer able to regulate body temperature;
the body’s inability to sweat is often brought on by dehydration
7.
Describe two health risks of exercising in the cold, including cold water.
[2]
Hypothermia – prolonged exposure to the cold, the process of
conduction and convection are responsible for cold related
2 Frostbite – freezing of the body’s tissues due to vasoconstriction
or the lack of blood flow to the extremities.
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8.
Describe how an athlete should acclimatize to heat stress. [2]
●
●
2
Arrive early at the area where the event is to be held
Allow anywhere from 5-10 days or the body to acclimatize –
repeated exposure to the heat improves the body’s ability to get
rid of heat.
IB SEHS SL
Option A.2 Quiz
●
9.
Gradually increase intensity to reduce the risk of heat illness
What are the two principal means by which the body maintains core
temperature in cold environments? [2]
Shivering – involves involuntary cycle of contraction and
relaxation of the muscles.
● Non-shivering - stimulation of metabolism using
brown/subcutaneous fat.
● Peripheral vasoconstriction – reduces blood flow to the skin to
try to keep the heat in.
●
10.
Discuss the significance of humidity and wind in relation to body heat
loss. [2]
Humidity makes it difficult for the body to cool down because
there is too much moisture in the air, which makes it difficult or
impossible for sweat to evaporate.
● Wind – aids in cooling the body down, however, if the speed of the
wind (wind chill) is high
●
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