The Influence of Exercise on The Circulatory System

The circulatory system (also known as the cardiovascular system) is a network of organs and tissues present in the human body, and is vital for living. It uses blood to transport gases, nutrients, hormones, immune cells and heat around the body and removes waste products from the body. The circulatory system consists of the heart, lungs, arteries, veins and capillaries, which all work in unison to transport blood to around the body.

Cellular respiration is a process, where body cells break down sugars into an energy form (ATP stores) that can be used by the muscles in the body. The process requires oxygen, and when muscles contract and use the energy, one of the major waste products created is carbon dioxide. The circulatory system collects oxygen from alveoli in the lungs and delivers it to body tissues so that cellular respiration can be performed and returns the deoxygenated blood (oxygen is used up in cellular respiration) back to the heart so that it can be pumped to the lungs again for oxygenation.

Throughout completing physical exercise cellular respiration is the common process of breaking sugar into a form that the cell can use as energy. Cellular respiration takes in food and uses it to create ATP, (adenosine triphosphate) a chemical which the cell uses for energy. Usually, this method requires oxygen, and is usually known as aerobic respiration, the equation for cellular respiration is glucose + oxygen. The term homeostasis is referred to as the tendency towards a relatively stable equilibrium between interdependent elements, maintained by physiological processes, as the endocrine system plays an important role in homeostasis as hormones must regulate the activity of body cells, meaning the release of hormones into the blood is controlled by a stimulus. During homeostasis, the body increases sweat production, heart and breathing rate, to maintain a healthy homeostatic system.

Homeostasis depends on the ability of the body to detect or oppose these changes. Through relevant exercise conducted (jumping jacks), it is evident there is an obvious increase in physical activity, as muscle cells breathe more than they do when the body is at rest. As the heart rate increases during exercise, so too does the rate and depth of breathing, this occurs to ensure that more oxygen is absorbed into the blood stream, and more carbon dioxide is removed from the body. 

Furthermore, capillaries allow for a gas exchange of oxygen and carbon dioxide to occur because they surround the alveoli and have thin, single-celled walls that make the gas diffusion process easy. When blood arrives in the alveoli with a higher CO2 and lower oxygen concentration (produced as a result of cellular respiration) it diffuses through capillaries with the alveolar air, which has a much lower CO2 and higher oxygen concentration. This means that there is a concentration gradient which allows the CO2 to diffuse out of the blood and into the alveolar air. Due to the alveolar air having a higher oxygen concentration, the oxygen diffuses into the blood through capillaries, combining with haemoglobin in red blood cells to form oxyhaemoglobin. The blood is oxygen rich now and is ready for cellular respiration again .

Overall, the heart must be able to pump blood at a rate so that there is always a constant and adequate supply of oxygen available to the body for cellular respiration to be performed. The amount of blood the heart pumps per minute can be described as cardiac output. When energy is used, such as during exercise, the body needs a greater cardiac output to keep functioning properly, so the heart is stimulated to pump blood faster and more forcefully, causing for a higher heart rate.