1. Why is more energy needed during exercise?
2. Where does this extra energy come from?
3. What 3 things happen during exercise to get more oxygen to the muscles?
4. When do muscle cells start to respire anaerobically?
5. What substance builds up in the muscles when they respire anaerobically?
6. What is muscle fatigue?
7. What is an oxygen debt?
8. When oxygen reacts with lactic acid what 2 products are formed?
9. What does your body continue to do after you stop exercising to get the extra oxygen to repay the debt?
10. Why does the pulse and breathing rate stay high for a while after you stop exercising?
11. What is the other way of getting rid of lactic acid? Which organ is involved? What is lactic acid converted into?

1) The muscles need more energy as the breathing rate and heart rate increase to bring more oxygen into the body and remove carbon dioxide. More energy is needed to supply muscles with extra oxygen and remove carbon dioxide.

2) Glycogen in the muscles.

3) Rate and volume of breathing increases,

Cardiac output is increased,

Blood flow from nonessential organs is provided to the working muscle.

4) Muscle cells respire anaerobically when there is a temporary deficiency of oxygen during high intensity exercises.

5) Lactic acid.

6) Muscle fatigue is when the muscle cannot perform as normal (decline of ability) due to a result of vigorous exercise.

7) A temporary oxygen shortage in the body tissues due to exercise.

8) Oxygen+ Lactic acid goes to Carbon dioxide + water.

9) The body continues to respire in order to get more oxygen and remove carbon dioxide.

10) The heart rate and breathing rate stay high after exercise in order to repay the oxygen debt and remove carbon dioxide. They also have to reduce the acid based balance in the muscles to neutral.

11) Lactic acid can also removed by being converted into Glycogen. This involves the muscles as glycogen is a product of the muscles

Hope this helps!