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Circulatory System - Coggle Diagram
Circulatory System
The heart
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It is a pumping organ that keeps the blood flowing around the body. The walls of the heart are made mostly of muscle tissue.
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The heart uses its four chambers (right atrium, right ventricle, left atrium and left ventricle) to pump the blood around
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2 - The atria contract, which pushes the blood into the ventricles.
3 - The ventricles contract, which forces the blood into the pulmonary artery and the aorta, and then out of the heart
4 - The blood then flows to the organs through arteries, and returns through veins.
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The heart also has its own pacemaker. Your resting heart rate is controlled by a group of cells in the right atrium wall that act as a pacemaker.
Blood vessels
There are three different types of blood vessels - arteries, capillaries and veins.
Arteries
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They contain thick layers of muscle to make them strong, and they have elastic fibers to allow them to stretch and spring back.
Capillaries
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They have permeable walls, so that substances can diffuse in and out
They supply food and oxygen, and then take away waste like CO2.
Their walls are usually only one cell thick. This increases the rate of diffusion by decreasing the distance over which it occurs.
Veins
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Veins have a bigger lumen than arteries so that it helps the blood to flow despite the lower pressure.
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Blood
Blood is a tissue. One of its jobs is to act as a big transport system. There are four main things in blood.
Red blood cells
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Their shape is a biconcave disc, this gives a large surface area for absorbing oxygen.
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In the lungs, haemoglobin binds to oxygen to become oxyhaemoglobin. Then in body tissues, this reverses and it splits into haemoglobin and oxygen, to release oxygen to the cells
White blood cells
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Some produce antibodies to fight microorganisms, as well as antitoxins to neutralise any toxins
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Platelets
Small fragments of cells, and they have no nucleus
They help the blood to clot at a wound, to stop the blood pouring out and to stop microorganisms getting in
Plasma
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It carries: red and white blood cells and platelets, nutrients, carbon dioxide and many other things
What is it?
The circulatory system carries food and oxygen to every cell in the body. It also carries waste products to where they can be removed from the body.
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The circulatory system is made up of the heart, blood vessels and blood.