3. White blood cells / WBCs (leucocytes) living / organic --> colourless cells that have a nucleus and mitochondria but do not contain haemoglobin

They are much bigger than RBCs
Some move like amoeba and feed on pathogens by phagocytosis (phagocytes)
Some produce antibodies - specific defence proteins
Made in bone marrow and lymphatic tissue.
They can survive for many hours to several years
approx. 8000 mm³
Also function to remove cell debris
They are not confined to the bloodstream - can pass into the tissue and lymphatic tissue.

*Leukaemia is a form of cancer in which white blood cells are produced too rapidly and are immature. They crowd out other blood cells and may cause anaemia, increased risk of infection and reduceed ability to clot the blood. Leukaemia may be treated by radiation or drugs.

SPECIALISED WBCs

Monocytes/macrophages - The largest of the WBCs making up to 4-8% of the blood. They engulf pathogens, viruses, cancer cells, and tissues by phagocytosis (formed in bone marrow).
Lymphocytes - Made in bone marrow and stored in parts of the lymphatic tissue e.g. spleen / lymph nodes / tonsils and move using pseudopodia, account for 20-25% of WBCs. Produce antibodies.

Role: Defend the body against infection.

	Created by eimearkelly3 over 11 years ago

Leaving Certificate Biology (The Blood) Note on The Blood, created by eimearkelly3 on 17/08/2013.