During Cardio-respiratory endurance activity the blood vessels carry to the working muscles. Protein
Fat
Oxygen
Potassium

The respiratory system transports oxygen from the air we breathe, through a system of tubes, into our lungs and then diffuses it into the bloodstream, whilst carbon dioxide makes the opposite journey.

Explanation:

The cardio-respiratory system works together to get oxygen to the working muscles and remove carbon dioxide from the body.

During exercise the muscles need more oxygen in order to contract and they produce more carbon dioxide as a waste product. To meet this increased demand by the muscles, the following happens:

Breathing depth (tidal volume) and rate increase – this gets more oxygen into the lungs and removes more carbon dioxide out of the lungs.

Graph showing the lung volume in litres of a person during rest and exercise over time.

The graph shows that as a person goes from rest to exercise, their tidal volume increases.

Heart rate increases – this increases the rate that oxygen is transported from the blood to the working muscles and carbon dioxide is transported from the working muscles to the lungs.

Graph showing the heart rate in BPM of a person at rest, during exercise and after exercise.

This graph indicates the following:

the person's resting heart rate is around 60 bpm

at 8 minutes, just before taking part in exercise their heart rate increases – this is called the anticipatory increase in heart rate which occurs when a person starts to think about taking part in exercise

at 10 minutes the person starts to take part in exercise and there is a steep increase in heart rate which reaches 145 bpm at 13 minutes

the heart rate remains high during exercise

when the person stops taking part in exercise the heart rate decreases