The Healthy Performer (5) (Circulatory & Respiratory & Nervous Systems)

Circulatory System

• The circulatory system functions in the delivery of oxygen, nutrient molecules and hormones. It also functions in the removal of carbon dioxide, ammonia and other metabolic wastes.
• The three components of the circulatory system are the heart, blood vessels and the blood itself.
• The heart beats approximately 100'00 times a day, and the beating sound we hear is the clap of valve leaflets opening and closing.
• The heart is a cardiac muscle as it never gets fatigued, meaning it can continue working without ever getting tired. It is protected by the ribcage. It acts as a pump, pushing blood all around the body. It is separated into two sides (by the septum) as to ensure oxygenated and de-oxygenated blood don't mix. Blood only flows one way due to valves. 
• There are three types of blood vessels: arteries (carries de-oxygenated blood to the lungs), veins (carries oxygenated blood to the heart and the rest of the body) and capillaries (one cell thick - transfer site of oxygen and other nutrients from the bloodstream to other tissues).
• De-oxygenated blood is pumped from the heart to the lungs (via the pulmonary artery), where the blood becomes oxygenated, and then the blood is returned to the heart (via the pulmonary vein).
• The circulatory system is essential for getting blood to different parts of the body; ensuring you have good circulation means you shouldn't become numb in certain areas. Having full feeling means you can feel what you are doing and so can correct and perfect your movements.
• Knowing about this system can help a performer in training as they would be aware of their heartbeat and how to improve their overall fitness (by improving the strength of their heart)

Respiratory System

• The human respiratory system is a series of organs responsible for taking in oxygen and expelling carbon dioxide.
• As we breathe in, air enters our nasal cavity (where the temperature and humidity is regulated by the sinuses). The trachea then filters the air. The diaphragm lowers and the intercostal muscles contract to allow the ribcage to expand, allowing the lung capacity to increase. As we breathe out, the ribcage contracts and the diaphragm forms a dome shape again, causing the lung capacity to decrease, to squeeze more air out of the lungs.
• Carbon dioxide is expelled by breathing, where we break down glucose and oxygen into carbon dioxide and water. Water is lost through sweat and urine.
• A large lung capacity means you would have good breathe control and a strong diaphragm enables you to support your voice effectively. Knowing about this system would make performers conscious of their lungs and diaphragm and their importance - understanding their importance may encourage them to try and use them more effectively.

Nervous System

• "The network of nerve cells and fibres which transmits nerve impulses between parts of the body".
• Stimulus --> receptor --> sensory neurone --> relay neurone --> motor neurone --> effector --> response.
• The nervous system enables you to respond to different events. For example, if you saw in your peripheral vision that another dancer was too close to you and was going to kick you, you could move out of their way.
• Knowing about the nervous system would make performers conscious of their bodies and they could learn about how to look after their bodies.