4.2.2: Response to exercise
Not started yet — this one needs some love.
During exercise, the body reacts to the increased demand for energy.
Heart rate, breathing rate and breath volume increase to supply muscles with more oxygenated blood.
If insufficient oxygen is supplied, anaerobic respiration takes place in muscles.
Incomplete oxidation of glucose causes a build-up of lactic acid and creates an oxygen debt.
During long periods of vigorous activity, muscles become fatigued and stop contracting efficiently.
(HT) Blood transports lactic acid from muscles to the liver, where it is converted back into glucose.
(HT) Oxygen debt is the amount of extra oxygen the body needs after exercise to react with accumulated lactic acid and remove it from cells.
Common exam mistakes
Do not say heart rate increases to send more carbon dioxide to muscles; the key supply is oxygenated blood.
Do not describe oxygen debt as oxygen needed during exercise; it is extra oxygen needed after exercise.
Do not say lactic acid is converted back to glucose in the muscles, lungs or kidneys; at Higher tier it is converted in the liver.
Do not just write tiredness for fatigue; link it to muscles stopping contracting efficiently.