There are several components in human blood that we need to know in I/GCSE Biology. 👇🏻 👇🏻 👇🏻

Red blood cell

• Contain haemoglobin which carries oxygen
• Made in the bone marrow. The more you train the more red blood cells are made.
• Have no nucleus to allow more space for oxygen
• Biconcave disc shape - greater surface area and allows cell to move through small spaces

White blood cells

• Protect the body by fighting disease

Plasma

• Fluid part of blood
• Carries carbon dioxide, hormones and waste

Platelets

• Clump together to form clots
• Protect the body by stopping bleeding

There are various types of blood vessels that we need to know in I/GCSE Biology. 👇🏻 👇🏻 👇🏻

Artery

• Carry blood away from the heart (always oxygenated apart from the pulmonary artery which goes to the lungs)
• Have thick muscular walls - to withstand pressure
• Have small passageways for blood (internal lumen)
• Contain blood under high pressure

Vein

• Carry blood to the heart (always de-oxygenated apart from the pulmonary vein which goes from the lungs to the heart)
• Have thin walls
• Have larger internal lumen
• Contain blood under low pressure
• Have valves to prevent blood flowing backwards

Capillaries

• Found in the muscles and lungs
• Microscopic – one cell thick
• Very low blood pressure
• Where gas exchange takes place. Oxygen passes through the capillary wall and into the tissues, carbon dioxide passes from the tissues into the blood

That's the end of the topic!

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Drafted by Joey (Biology)

Reference:

https://getrevising.co.uk/revision-notes/biology_b3_the_circulatory_system_and_blood_4

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