Immunity Flashcards
What are phagocytes?
scavenger cells present in the body and blood which remove dead cells and pathogens
What are macrophages?
type of phagocyte found settled in organs (monocytes in blood), long-lived
What are neutrophils?
type of phagocyte and white blood cell which patrols body, released in large number during infections, short-lived
What is the mode of action of phagocytes?
macrophages split pathogens to display their antigens to lymphocytes, neutrophils do phagocytosis (chemotaxis, recognition and attachment, endocytosis, phagocytic vacuole, phagosome, killing and digestion)
Where do phagocytes originate?
bone marrow
What are B-lymphocytes?
a type of lymphocyte, which is a type of white blood cell, remain in blood cell until maturity, then spread through body, concentrated in lymph nodes and spleen
What is the mode of action of B-lymphocytes?
B-cells gain the ability to make one type of antibody as they mature, they divide to make a clone, antibodies remain in B-cell and form part of glycoprotein receptor, which can combine with a specific antigen, B-cells are activated during immune response, in which clonal selection and expansion happens, some activated B-cells become plasma cells, some become memory cells
What are T-lymphocytes?
a type of lymphocyte, which is a type of white blood cell, leave bone marrow and mature in thymus
What is the mode of action of T-lymphocytes?
T cell receptors are specific to one antigen, when activated, T cells go through clonal selection and expansion, helper T cells release cytokines that stimulate B cells to divide or macrophages to work, killer T cells look for invaded cells displaying foreign antigens and kill them by attaching and secreting toxic substances, memory helper and killer T cells are formed
What is the significance of increase in white blood cell counts?
an increase in neutrophils indicates a bacterial infection or the inflammation and death of tissue, an increase in lymphocytes indicates a viral infection or tuberculosis
What is leukaemia?
cancers of the stem cells in the bone marrow which produce neutrophils, macrophages, platelets, and lymphocytes
What is myeloid leukaemia?
cancer of the stem cells which produce neutrophils, macrophages, and platelets
What is lymphoid leukaemia?
cancer of the stem cells which produce lymphocytes
What is immune response?
a series of responses of the body involving lymphocytes and neutrophils to the detection of foreign antigens
What is an antigen?
a substance foreign to the body which stimulates an immune response
What is self and non-self?
self is any substance in the body not recognised as foreign by the immune system