I have taken some preliminary results to see if the exercise would work.
The preliminary work showed that the exercise would work and helped me to work out a prediction. I predict the harder the subject exercises, the higher the subjects heart rate would be. The blood has to be pumped round the body quicker by the heart. There are several reasons why this happens; before and during the early stages of exercise the sympathetic nervous system is alerted and adrenaline is secreted in to the bloodstream. Triggered by impulses from the brain before exercise, the heart beats faster and general constriction of the arterioles except for those serving vital organs so that the blood under high pressure is diverted to the active muscles.
The pacemaker is called the sinus node. It's a small mass of specialized cells in the top of the heart's right atrium. It makes the electrical impulses that cause your heart to beat. It can control the rate in which it beats as well.
The metabolic rate increases. This is caused by the shortage of ATP. The increased metabolic rate results in carbon dioxide building up in muscle tissue. If the level of carbon dioxide builds up then this is monitored by chemoreceptors. This makes adjustments in the ventilation rate because you need more oxygen to replace the carbon dioxide. The heart rate increases to carry the waste away and replace it with oxygen quicker.
Rapid movement of limbs stimulates receptors in the skeletal muscles and tendons. These transmit impulses to the heart, leading to a further increase in the heart rate.
Conclusion
There is a genuine pattern in my results; the harder you exercise, the faster the heart beats, which proved that the prediction I made earlier was correct. The reason this happens is because when you move faster, the muscles need more oxygen and glucose. The muscles get these by respiration. The oxygen is carried round the body to the muscles in oxy-haemoglobin in the red blood cells and the glucose is dissolved in the blood plasma.
Cellular respiration is the process of oxidizing food molecules, like glucose, to carbon dioxide and water, which takes place in the mitochondria. The energy released is trapped in the form of ATP for use by all the energy-consuming activities of the cell.
There are more mitochondria in muscle cells than skin cells because the skin cells do not have to do much work, whereas the muscles work quite a lot.
ATP releases energy for the muscle cells to work. ATP is composed of three components. At the centre is a sugar molecule (ribose); attached to one side of this is an adenine molecule. On the other side are 3 phosphate molecules. These are the main part to the activity of ATP. ATP works by losing the end phosphate molecule when told to do so by an enzyme. This reaction releases a lot of energy, which organisms can used to contract muscles and other functions. This produces adenosine diphosphate, and then the end phosphate molecule can be removed to release even more energy.
The line in the graph is curved because there is a limit to how fast the heart can beat. The blood comes into the atria of the heart from the veins, it then drops into the ventricles and is pumped out and into the arteries, to go around the body. If the heart beats too fast then not enough blood can drop into the ventricles and the blood does not work fully.