The effect of Exercise on Pulse rate

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The effect of Exercise on Pulse rate

In this experiment I am going to be looking at how exercise affects the pulse rate of the body. By the end of the experiment I hope to have found a connection between exercise and how it affects the pulse rate (for example, does the pulse rated increase or decrease?). I will study this by taking a group of students and asking them to exercise for a short amount of time, taking their pulse before and after this exercise to find out if there is any change in the rate of it.

Hypothesis and Biological knowledge

The heart is a huge muscle found in the chest. The main use of the heart is to pump blood, which delivers oxygen, glucose and much-needed chemicals to other parts of the body.

The muscle making up the heart is called Cardiac muscle; this special muscle does not wear down as other muscle does in the body. This is because it has to constantly beat to keep us alive, so cannot die out and be replaced by new muscle. The cardiac muscle also has another difference to any other muscle that we find in places like our legs or arms, this is that it has it's own beat, moving to make the whole heart pump, this type of muscle is called myogenic muscle, which means (moves on it's own).

There are three sections to how the heart pumps. As the heart never stops pumping these three stages carry on in a circle.

Diastole is when the muscles of the heart relax. This allows oxygenated blood to rush in to the left atria and de-oxygenated blood in to the right atria. As the blood enters the atrium they swell and the pressure inside them increase.

Atria Systole - This process means the contraction of the atria. As the pressure in the atrium increases and more blood rushes in to it there is more and more pressure placed on the valves between the atria and the ventricles. Once the atrium are full the valves leading from the blood vessels delivering the oxygen close, not allowing anymore blood in to the heart. Once this happens the valves from the atrium to the ventricles open and the atria contract, pushing the blood through in to the ventricles. (The valve between the atria and ventricle on the left hand side of the heart is called the bicuspid valve, and on the right hand side it is called the tricuspid valve).

Ventricular Systole is the contraction of the ventricles. This happens once all the blood from the atrium have entered the ventricles and the bicuspid and tricuspid valves have closed, stopping the blood flowing backwards in to the atria again. Just as in the atrium the pressure inside the ventricles increases until the blood pushes open the semi-lunar valves and rushing out of the heart. Once the blood has been successfully pumped out of the heart the semi-lunar valves close very quickly, stopping the blood from flowing backwards in to the heart.

As the blood is pushed out of the heart it travels along arteries, towards the different parts of the body where it will be needed.

Arteries and veins are known as blood vessels, they carry blood around the body, centring around the heart and lungs. They are different in the way that they are made up, because they have different jobs.

(Reference: http://www.sci.sdsu.edu/class/bio590/pictures/lect5/artery-vein.jpeg)

Veins have thin walls; this is because the pressure in the veins is less than the arteries. Veins carry blood towards the heart and lungs; this means that it is coming from places in our bodies where the blood has been exchanging foods and energy. As it reaches these places the blood has to be forced through tiny blood vessels called capillaries, as this happens the pressure in the vessels builds up and energy is released, after the blood comes out of these capillaries the pressure is quite low as the energy has been used to push them through. As the pressure is so low the walls do not need to be very thick to withstand it, but they do have valves in them to stop the blood from flowing backwards on it's way back to the heart.
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Arteries have much thicker wall than veins. This is because the pressure in them is much greater as they come straight from the heart, and the blood is being pumped very fast. Arteries come from the heart; they collect oxygenated blood from the lungs and deliver it to other parts of the body. The pressure in the arteries is so high because the blood has to be pumped all over the body, going down to our toes is easy as it follows the laws of gravity and falls, but it takes enormous effort for the blood to go ...

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