‘Humans heart is like two pumps working side-by-side. Each one is made of two muscular parts: an atrium at the top, and a ventricle at the bottom. During a heartbeat, the atrium contracts, and forces blood into the ventricle. The ventricle contracts a split-second later, forcing blood out of the heart and into the arteries. The right side of the heart pumps blood from the body to the lungs. The left side takes oxygen-rich blood from the lungs and pumps it to the rest of the body’
From Dorling Kindersley, science encyclopedia.
If you are overweight and your heart has not been kept fit enough, your pulse rate will be higher as your cells need more energy. If the pulse rate is higher that means your heart is pumping very fast to get all energy and oxygen to its place. Here is a picture from which I have found on Encarta below-
Blood
Blood is a fluid that acts as a conveyor belt, which carries oxygen to all living cells in your body. It transports food substances, waste products and it is also your main defence for fighting diseases. Plasma carries most of the carbon dioxide to allow it to be exhaled back out. The red blood cell has no nucleus so that haemoglobin can fit in. Haemoglobin contains iron (which makes the blood obtain its colour) and it is important as it can make temporary bonds with gas molecules. When the haemoglobin meets with oxygen, it then is called oxyhaemoglobin, which then starts to travel to give cells the oxygen. This is explained in further detail below.
Respiration
Respiration is very important as it helps to obtain energy for movement, for growth, to make specialised cells for reproduction and in some cases, to keep their body at a constant temperature. Respiration normally uses carbohydrates to provide energy because it is easier to release energy from them than proteins. Respiration takes place in living cells like the mitochondria. Energy or food is reacted with oxygen, releasing energy and waste substances. The waste is in the form of carbon dioxide and water.
Food is turned into glucose before respiration takes place. This type of respiration just mentioned is called Aerobic respiration, because it uses oxygen from the air.
Here is the summarised aerobic word equation:
Glucose + oxygen Energy is released Carbon dioxide + water.
The chemical symbol equation is:
C6H12O6 + 6O2 Energy is released 6CO2 + 6H2O
The following picture and additional information of cellular respiration helps in understanding the process-
‘Cellular respiration is similar in most organisms, from simple one-celled bacteria, amoebas, and diatoms to complex plants like trees, and large Animals such as elephants, whales, and human beings. In most organisms apart from prokaryotes (chiefly bacteria and blue-green algae) cellular respiration takes place in the tiny sausage-shaped organelles within the cell called mitochondria.
In fact there are two versions of cellular respiration (both described in more detail in their separate articles, Aerobic Respiration, and Anaerobic Respiration). Aerobic respiration requires oxygen to break down high-energy fuel molecules—typically a simple sugar such as glucose (blood sugar)—through a series of chemical stages. The results are carbon dioxide, water, and energy in the form of molecules of ATP—the cell’s standard energy-carrier. The biochemical stages in the breakdown of glucose form a circular pathway or cycle known as the Krebs cycle or citric acid cycle.
Anaerobic respiration involves the breakdown of high-energy molecules, again typically glucose, but without the need for oxygen and therefore without the need for physical respiration (breathing). This version incorporates the chemical pathway termed glycolysis and results in lactic acid. It occurs as a matter of course in certain bacteria and other microbes called obligate anaerobes. It is also used as a reserve or emergency form of obtaining energy in other organisms, usually when oxygen is in short supply.’
Microsoft® Encarta® Reference Library 2002. © 1993-2001 Microsoft Corporation. All rights reserved.
Method
The following is the step-by-step procedure to how I will carry out the investigation. It also includes a fair test to make sure that there is absolutely no cheating and to make it a better investigation.
- I will firstly get the objects as needed such as the chair and the stopwatch.
- Secondly, I will ask questions such as do you smoke? Or are you overweight?
- I will measure their pulse rate (known as the resting pulse rate) before he has taken the exercise.
- Now, I will take the exercise for 15 seconds and then times it by 4 (this makes it add up to one minute)
- I will wait 2 minutes so that his heart rate has returned to normal.
- As soon as the procedure is done I will record the results.
- Then I will repeat the process till I have finished.
I am going to describe the investigation by seeing how I will make it a fair test. To make this a fair test-
- I will firstly make sure the stopwatch has not got a short battery or it is malfunctioning.
- I will always have the same chair so the height is not changed.
- Make sure the pulse is counted correctly and by concentrating on the pulse itself without getting distracted.
The safety for this investigation should be tight as pupils could get injured. Here is some of what I have come up with-
- Get a very steady chair, not wobbly or crooked as it can break easily.
- Make sure the pupils have not got a disability such as a recent injured leg.
My prediction for the investigation is that the pulse rate will go up as when you exercise your muscles or other helpful organs waste a lot of your energy or in scientific terms, uses up a lot of glucose and oxygen, it is then needed to quickly gain more. To do this the heart has to beat faster which means the oxygen is transported faster.
Conclusion
My results table and the results show that the person has an average heart rate, which also means that the person is fit. My graph is very accurate to my results as I did it the more accurate way, which was by putting the dot on the graph and then putting a circle around it. According to my prediction, I reckon I was correct but not as perfect as possible.
Evaluation
I suppose my investigation was ok but not perfect. Our task went on well but we could off improved it by making the range of exercise much longer so we get a more accurate answer of our investigation. This could also be improved by investigating more people’s pulses to see if the same does happen to that particular person.
