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Biology B4 - Coggle Diagram
Biology B4
Helping the heart
The resting heart rate is controlled by a group of cells in the right atria that form a natural pacemaker
Artificial pacemakers can be installed for people who have suffered heart attacks
Artificial hearts can be used temporarily while a patient waits for transplant
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The blood
The blood, blood vessels and heart make up the human circulatory system
Components of blood:
- Plasma, substance in which blood cells, chemicals and proteins are suspended, most of the blood is plasma.
- Red blood cells, cells with no nucleus and a large SA that possesses haemoglobin so oxygen binds to it, carry oxygen to cells
- White blood cells, defend the body against pathogens
- Platelets, cell fragments that clot to hole up wound sites
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Blood vessels
There are 3 different types of blood cell, which are all designed to move blood around the body
Arteries are the largest vessel, they carry oxygenated blood from the heart to the body, have thick muscly walls for protection, and are highly pressurised.
Veins are generally smaller and are designed to carry deoxygenated (used) from the body to the heart to be re-oxygenated, They have thinner walls and possess valves to prevent back flow
Capillaries are the smallest type of vessel. Their walls are one cell thick as they are the sight where the blood exchanges substances with the cells of the body via diffusion. They are also in large numbers to further increase efficiency.
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