Help me answer this human biology respiration question please! ?

Question

the harder your body works the more oxygen it needs so the heart has to pump more oxygen molecules (making heart beat faster). why does the body need more oxygen molecules though..?

Answer 1

This is a very interesting question. First, each cell in the body needs oxygen to function properly. Their oxygen requirements depends on their activity; less activity, less requirement. As the activity increases, more oxygen is needed. Usually, enough oxygen is circulating around our body. But if the activity increases some more, the cells in that particularly active organ will extract relatively more oxygen from the blood to sustain it's needs. If the oxygen supply does not meet the demand, the cells won't work efficiently. As such the body has to find ways to increase oxygen supply. Breathing is the key here, since we get oxygen mostly from the atmosphere. The heart actually beats faster so more blood, which is filled with oxygen, can be delivered to the whole body.

Answer 2

The body needs energy to work. Energy in the body comes in the form of ATP, to make ATP you need glucose (comes from carbohydrates mostly but you can get it from fats too) and oxygen molecules. These go through a load of complicated processes like Krebs cycle and glycolysis but ultimately you end up with the ATP you need to make the body work! The harder your body's working, like muscle contraction when you exercises, the more energy it needs thus the more ATP it needs and so the more oxygen it needs. The name for the conversion of glucose and oxygen to ATP and carbon dioxide is respiration.

The equation for it is

Glucose + Oxygen --> Carbon Dioxide + Water

The energy released in this process is used to convert:

ADP + PI (inorganic phosphate) --> ATP

When ATP is broken down back to ADP + Pi the energy is released for use by the body - usually muscles but cells use it for growth and such. But i don't know if you need so much detail.