When doing physical activity, just about every system gives all its effort on helping the muscles do their work. The muscles take in energy and use it to have more force.
The pulse increased considerably every time the physical activity level went up. When doing physical activity, it is normal that the heartbeat quickens to pump blood in the body faster. While doing physical activity, the heart must pump blood faster for it to transport oxygen to the muscles and eliminate waste products. Exercise reduces the amount of oxygen in the body, and the level of lactic acids and waste products increase, the heart has to pump faster in order supply the demands of the cells.
Each cell in the muscles needed more oxygen when doing more work because of increased cellular respiration within the cell.
Each cell also required glucose, which is part of cellular respiration. Glucose is produced by the process of breaking down carbohydrates in the digestive system. Examples of these carbohydrates could be starches (chains of many sugars) or simple sugars. The digestive system breaks down drinks and foods in the body to build and nourish cells and also to provide energy.
Two substances produced during cellular respiration are carbon dioxide and water. The formula for cellular respiration is C6H12O6 + 6O2 ‡ 6CO2 + 6H2O + Energy.
Blood is the transport system for oxygen, glucose, carbon dioxide and part of the water. Blood is made up of 4 main elements: red blood cells (erythrocytes), white blood cells, platelets, and plasma.
Oxygen in the blood is carried by a system of tubules made-up of arteries, arterioles, and capillaries. Oxygen diffuses from the high concentration in the arterial capillaries into the area of low concentration in the cell. Oxygen attaches itself to the erythrocytes that are red blood cells. Erythrocytes contain hemoglobin, which is a molecule that contains an iron atom. Oxygen binds itself to that iron atom.
Carbon dioxide diffuses from the high concentration in the cells into the area of low concentration in capillaries around the cell. The capillaries carry the blood rich in carbon dioxide to the venules and then to the veins. The veins carry the carbon dioxide to the upper and lower vena cava that lead into the right atrium, then to the right ventricle. From there, it leads itself to the alveoli passing through many different tubes and then reaches the bronchioles. It then goes up in the trachea, into the epiglottis where it is diffused by the nose or mouth.
Receptors, such as the one in the aorta, detect the rise in carbon dioxide in the body as the blood leaves the left ventricle. The carbon dioxide receptor examines the level of carbon dioxide in the blood. The receptor sends a signal to respiratory centre in response to an increase or decrease in the levels of carbon dioxide. The respiratory centre is located in the medulla oblongata at the base of the brain.
In order to convert glucose into energy for the cells in our body while doing physical activity, we must take breaths faster and more often to supply the body’s demand in oxygen. While doing physical activity, the muscles consume more oxygen. This is another reason to breath more while practicing a higher level of exercise.
The respiratory centre, which is part of the central nervous system (the largest part of the nervous system, which includes the brain and the spinal chord) and part of the autonomous nervous system, sends a signal to the muscles involved with respiration such as the intercostal muscles in the rib cage and the diaphragm to work faster if the levels of carbon dioxide have increased. These signals occur very quickly. During the intense activity level the abdominal muscles were also activated by the respiratory system. This was not part of the procedures so in the next repetition of the experiment this should be included in the procedures as one of the variables to observe.
As the muscles around the lungs contract, they enlarge the area around the lungs. The enlarged area around the lungs decreases the pressure in the lungs. The pressure outside the body is greater at that point than in the lungs so air from the outside is forced into the lungs by the difference in pressure. As the muscles relax and return to their original positions, the higher pressure on the lungs forces air from the lungs into the air.
The lungs are comprised of two main sections: The left and the right lungs. Air from the outside enters through the nose and mouth. It then passes through the larynx and the trachea (a tube that enters the chest cavity.) There, the trachea splits into two smaller tubes called the bronchi (plural form of bronchus). Each of these divides again forming the bronchial tubes. These tubes lead to the lungs where they divide into many small tubes that connect to the alveoli. All this explains the increase in respiration rate.
The results in the experiment indicate that both respiration and pulse increased with higher activity levels. The mean results support the hypothesis. The range in the results can be explained by different levels of strenuous activities, some requiring more oxygen, and by different levels of fitness among the subjects.
It would be worthwhile to add a further dimension to the experiment by analyzing how long it takes the body to resume the normal pulse and respiration to determine when oxygen levels returned back to normal. The hypothesis would be the faster that the subject's pulse and respiration returned to normal, the better is the subject's cardiovascular and pulmonary systems. Another addition to the experiment would be to have some subjects inhale oxygen. The hypothesis would be that the subjects inhaling oxygen would return to their normal pulse and respiration rates faster than subjects who were not provided with oxygen.
The experiment could also test the level of carbon dioxide produced at the different levels of activity. This can be measured by having the subjects blow through a straw into lime water. Lime water turns murky white in the presence of carbon dioxide as done in a previous experiment this year. The faster the lime water turned milky white, the more carbon dioxide the subject must be exhaling.
Blood pressure is a pressure applied by the blood circulating against the walls of the blood vessels. The two types of blood pressures are systolic (right after your hear beats) and diastolic (in between heart beats). Aerobic work depends on the energy produced to supply the body’s demand in oxygen. The muscles that are used to do the physical activity has a higher demand of oxygen to function correctly which means we must breathe harder and faster to supply them. The heart must pump faster to help this process keep going properly, and as it beats faster it beats with a higher intensity, which increases the blood pressure.
The excretory system is the system in the body in which waste products are moved out of the body. Two main excretory products are sweat and carbon dioxide. As respiration occurs, carbon dioxide is produced as a waste product, as mentioned above. As the carbon dioxide level increases in the body, it leaves the cells and enters the blood stream, then leaves the blood into the lung tissues, in a process we call diffusion. Carbon dioxide then leaves the body every time we exhale. The second main waste product is sweat, which is a mixture of salt, water, and urea, three metabolic wastes. This mixture of waste products comes out of pores (very small openings) in the skin. This is how these products are excreted from the body, but how is sweat formed? In the skin, we have what are called sweat glands. These sweat glands allow the waste products to diffuse from the blood and into the glands. When the temperature of the body rises above normal levels, the change is sensed by a sensor in the brain and sends messages to the sweat glands. Sweat is then released from the glands going through a small tube and passing through the pores, reaching the skin surface. This explains why the sweat level increased as the level of physical activity increased.
While doing physical activity, 70% of the energy produced for the muscles is lost in heat, raising the body temperature. The sweat released when the temperature rises cools down the skin. This is how I could explain the decrease of the external temperature during activity three for the external temperature. A second problem occurred with the temperature. During the second activity of the internal temperature, we can notice a sudden decrease of temperature. The explanation could be if there were malfunctions during the tests. For example, not taking the temperature quick enough after the activity, or using a defective thermometer. This could have easily happened during all tests. They are all possible sources of error for every test we took.
