1. Platelets (Thrombocytes)
Blood
Plasma (55%)
Platelets (Thrombocytes)
Blood cells

4. 90% water, 10% chemicals, slightly alkaline
What is blood plasma?
90% water, 10% chemicals, slightly alkaline
pH 7.4.
Transports chemicals and heat around the body
What sort of chemicals?
Important molecules such as glucose
Waste products
Mineral salts
Hormones
Plasma proteins
Respiratory gases

5. Blood cells

6. Red and white blood cells

7. Red Blood cells: Erythrocytes
They have no organelles including a nucleus to leave more room for haemoglobin.
Large surface area due their bi-concave disc shape. This allows O2 to diffuse quickly into and out of the cell
They have an elastic membrane which allows them to squeeze through small blood capillaries, then spring back into normal shape when they re-enter veins

8. White Blood Cells: Leucocytes
These are larger than red blood cells but there are fewer of them in the blood. They are responsible for fighting disease.
There are three different white blood cells for you to remember.

9. phagocytes: Monocytes & Neutrophils
These white blood cells engulf pathogens and microorganisms and digest them (phagocytosis ). A non specific process which occurs whatever the infection.
They have an elongated nucleus and a flowing cytoplasm – this enables them to squeeze through gaps between cells to move to the site of infection in body tissues
Their cytoplasm contains many lysosomes to aid digestion
Monocytes =Agranulocyte (non granular cytoplasm.
Neutrophil = Granulocyte (granular cytoplasm)

10. Lymphocytes (Agranulocytes)
Act against microorganisms, with some lymphocytes secreting antibodies (a range of glycoproteins) that between them immobilise and kill microorganisms and make them ready for phagocytes to engulf.
Large nucleus.
These white blood cells are specific. Each type of lymphocyte acts against one particular pathogen.
They provide long term immunity to future infections.