Biology 😎

Neutrophils

White blood cells found in the blood and tissues. They are granulated and phagocytic. They rapidly enter sites of pathogen entry, engulfing the pathogen and then dying en masse. This is the basis of pus formation.

Monocytes

White blood cells that circulate in the blood. They grow in the bone marrow and are released into the bloodstream. They respond to chemical mediators of inflammation and squeeze through the walls of the capillaries into the tissues, where they become macrophages.

Basophils

White blood cells with granulated cytoplasm that secrete chemicals, including histamines. These cells circulate in the blood and play a role in inflammatory and allergic reactions.

Plasma cells

Are B lymphocytes that secrete specific antibodies

Macrophages

Are found in the body tissues. They are large phagocytic cells that become powerful stimulators of an immune response when they engulf a pathogen.

Platelets

Cell fragments that assist blood clotting and wound repair, preventing the entry of micro-organisms into the body

Dendritic cells

Cells with membranous extensions that phagocytose pathogens, process them and present them to other cells of the immune system

Granulocytes

General term describing white blood cells that are granulated (neutrophils, basophils and eosinophils). They have a granular cytoplasm due to the presence of secretory vesicles that contain powerful chemicals.

Phagocytes

General term describing white blood cells that engulf and digest foreign pathogens in a process called phagocytosis. Neutrophils and macrophages are phagocytes.

Leukocytes

General term describing white blood cells.

Lymphocytes

General term for a range of specialised white blood cells that respond to specific antigens in the process of adaptive immunity

Mast cells

Granulated cells that release histamines; also involved in healing wounds. Mast cells are concentrated within the respiratory and gastrointestinal tracts, and within the deep layers of the skin.

NK cells

Granulated lymphocytes that secrete chemicals that lyse cancer cells and cells that are infected with viruses. They attach to the glycoproteins on the surface of infected cells and kill them

Eosinophils

Granulated white blood cells. Their secretory vesicles contain powerful enzymes that rupture (lyse) cell walls of pathogens. They are important in combating parasites, such as worms and flukes. Their chemicals are toxic to the host and parasite.

T lymphocytes

Originate in bone marrow then travel to the thymus where they mature. Contribute to the immune system in a variety of ways

B lymphocytes

Produced and matured in bone marrow, and travel to the spleen and lymph nodes. Produce specialised proteins called antibodies which bind to specific foreign material, thereby labelling it for engulfment and destruction by other white blood cells such as macrophages.

Cytotoxic T cells

T cells that contain lethal chemicals that destroy foreign, infected and altered cells

Helper T cells

T cells that help or activate other cells of the immune system

Regulatory T cells

T cells that suppress or turn off the activity of other cells once the threat has passed