Topic 4.3 - Circulation
- Created by: Alice Cullen
- Created on: 28-12-16 14:00
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- Substances are transported from where they enter the body to the cells or from the cells to where they are removed from the body, byt he circulatory system
- This system consists of the heart, the blood vessels and the blood
- The heart is an organ that pumps blood around the body
- Much of the wall of the heart is made from muscular tissue
- The heart has 4 main chambers
- The right and left atria and the right and left ventricles
- The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a natural pacemaker.
- Artificial pacemakers are electrical devices used to correct irregularities in the heart rate
- In coronary heart dsease, layers of fatty material build up inside the coronary arteries, narrowing them.
- This results in a lack of oxygen for the heart muscles
- Stents are then used to keep the arteries open
- In some people heart valves may become faulty, this could be because of two main faults:
- The heart valve tissue may stiffen, preventing the valve from opening fully
- The heart valve may have developed a leak
- Faulty valves can be replaced in two ways:
- Hiological valves- valves from humans or other mammals
- Mechanical valves
- Artificial Hearts are sometimes used to keep a patient alive while waiting for a heart transplant or to allow the hear to rest as an aid to recovery
- Blood enters the atria of the heart, the atria contracts and force blood into the ventricles…
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