Cell Organisation and the Circulatory System

Let's not over complicate, you need to know the 3 definitions. And that's a whole topic covered.

"A TISSUE is a group of similiar cells that work together to carry out a particular function"

"An ORGAN is a group of different tissues that work together to perform a particular function."

"An ORGAN SYSTEM is a group of organs working together to perform a particular function."

 The Circulatory System
4 chambers, one heart. Sounds like a romantic and yet sadistic sex film. And then four major blood vessels, not so sexual.

This is the order it works in:

1. Right atrium recieves deoxygenated blood from the body (through the VENA CAVA)
2. De-oxygenated blood moves through to the right ventricle which pumps it to the lungs.
3. The left atrium recieves the oxygenated blood (through the PULMONARY VEIN)
4. The oxygenated blood then moved through to the left ventricle and is pumped around the whole body.  (via the AORTA)

Or to put it in a shorter and simpler way:

De-oxygentated - vena cava - body - right ventricle - lungs - oxygenated blood - left atrium - left ventricle- aorta - whole body

Please don't sue me CGP...

A few important things to remember would be:

• 4 chambers in the heart
• 4 major blood vessels
• Left ventricle has a thicker wall that right ventricle
• Why? It pumps blood around the whole body so more force is needed due to more distance needed to be covered.
• VALVES prevent the backflow of blood.