Homeostasis is the process which the body internally is kept relatively stable despite changes in the environment. Your body is able to adapt to several conditions. For instance, average human body temperature is 37°C, varying slightly from person to person. When the temperature outside drops to 30 degrees, your body temperature remains the same, proving your body has the ability to regulate its own temperature. Along with temperature, there are many other ways in which your body regulates itself, especially during exercise. The heart is controlled by the sympathetic nervous system and the parasympathetic nervous system. These two systems control the rate of the heart, so it is beating enough oxygenated blood around the body to provide respiring muscle tissues with the right amount of oxygen. For example, when the body is exercising, more oxygen is needed in the muscles, so the heart needs to pump faster to accommodate this. The sympathetic nervous system is responsible for the increase of the heart rate during physical exercise, fear or stress. The parasympathetic nervous system slows down the heart rate during periods of rest. The Sino-atrial node sends electrical impulses around the heart muscle and tells it how fast it should be beating according to the impulses received from the parasympathetic and sympathetic nervous systems. Every few seconds, the Sino-atrial node sends out nerve impulses which branch across the atrial muscle fibres and cause a contraction. These impulses are received by the atrio-ventricular node which stimulates the second contraction of the heart. Another factor that effects the heart rate is adrenaline which is released from the adrenal gland during times of physical action, stress or fear. Adrenaline takes effect on the Sino-atrial node and…
