Circulatory System
Circulatory System
The circulatory system is how oxygen and nutrients are transported to all the tissues of the body via blood circulation. The heart pumps the blood through a series of tubes called veins, arteries and capillaries.
The heart consists of four separate chambers – the left atrium, the right atrium, the left ventricle and the right ventricle. The atria are at the top and they collect blood. The ventricles are at the bottom and they pump blood.
These four chambers are connected to two different circuits. Pulmonary circulation pumps blood from the right ventricle to the lungs where it exchanges waste carbon dioxide for oxygen. This oxygenated blood then returns to the left atrium.
This oxygen-rich blood passes to the left ventricle where it begins the second circuit – systemic circulation. The left ventricle pumps the blood around the body until it returns to the heart via the right atrium. It then passes to the right ventricle where the process begins again.
Arteries
The arteries are the tubes that carry blood away from the heart. They are strong and elastic to withstand the pressure of being pumped from the heart.
Veins
Veins carry blood back to the heart and contain valves to ensure the blood (no longer under pressure from the heart) keeps flowing towards the heart.
Capillaries
The Pulse
Checking a person’s pulse can help to identify how fast the heart is beating and whether it is working within the normal range. Although not required in first aid guidelines, if you know how to take a pulse it can provide more evidence during a secondary survey. The best place for a first aider to take a pulse are the neck (carotid), the wrist (radial) or the upper arm (brachial).
- Adult resting rate 60 – 90 beats per minute
- Child resting rate 90 – 100 beats per minute
- Infant resting rate 110 – 140 beats per minute
