B4 Exercise (page 56) Flashcards
When you exercise do you Respire more or less?
you respire more
(respire means to inhale and exhale air successfully)
Muscles need what? from respiration to contract?
your muscles need energy from respiration to contract.
When you exercise, what happens to some of your muscles?
they contract more frequently than normal so you need more energy. This energy comes from increased respiration.
The increase in respiration in your cells means what?
that you need to get more oxygen into them.
How do your body get more oxygen into the blood whist exercising?
by your breathing rate and breath volume increase will get more oxygen into the blood.
Why do your heart increase while exercising?
to get oxygenated blood around the body faster. This removes CO2 more quickly at the same time.
When you do really vigorous exercise (like sprinting) what happens with the oxygen to your muscles?
your body can’t supply oxygen to your muscles quickly enough, so they start respiring anaerobically (see page 55).
Why is respiring anaerobically not the best way to transfer energy from glucose?
because lactic acid builds up in the muscles, which gets painful.
(remember lactic acid is formed from the incomplete oxidation of glucose)
Long periods of exercise also cause muscle fatigue why?
because the muscles get tired and then stop contracting efficiently.
What happens after resorting to anaerobic respiration when you stop exercising?
you’ll have an “oxygen debt”
What is an “oxygen debt”?
it is the amount of extra oxygen your body needs to react with the build up of lactic acid and remove it from cells.
(in other words you have to “repay” the oxygen that you didn’t get to your muscles in time because your lungs, heart and blood couldn’t keep up with the demand earlier on.
This means you have to keep breathing hard for a while after you stop, to get more oxygen into your blood, which is transported to the muscle cells.
Oxygen reacts with the lactic acid to form what?
harmless CO2 and water.
After exercising, why do your pulse and breathing rate stay high for a while?
as there are high levels of lactic acid and CO2.
What other way does your body have a way of coping with high level of lactic acid?
the blood that enters your muscles transports the lactic acid to the liver. In the liver, the lactic acid is converted back to glucose.
How can you measure breathing rate?
by counting breaths, and heart rate by taking the pulse.
e.g.
you could take your pulse by sitting down for 5 minutes.
then after 5 minutes of gentle walking
then again after 5 minutes of slow jogging
ten again after running for 5 minutes.
and plot your results in a bar chart.
see diagram on page 56
