4.2- Specific Cellular Defences Flashcards
what are body tissues monitored by?
a range of white blood cells that constantly circulate and provide immune surveillance
what happens if tissues are damaged or invaded?
certain cells release cytokines, increasing blood flow to site of the damage or invasion
what does increased blood flow lead to?
the accumulation of specific white blood cells at the site of damage or infection
what does every lymphocyte have ?
a single type of membrane required receptor specific to one type of antigen
what fed a lymphocyte respond to?
respond to antigens on pathogen cells, infected cells or toxins released by pathogens
what happens when a lymphocyte binds to an antigen?
repeated cell division produces a clone of identical lymphocyte cells
what are the 2 broad categories of lymphocyte?
- T lymphocyte
- B lymphocyte
what is the clinal selection theory?
refers to the selection of lymphocyte by antigens producing a clone
why do T lymphocytes have specific surface proteins?
that allow them to distinguish between the surface molecules of the body’s own cells(self antigens) and cells with foreign molecules on their surfaces (non-self antigen)
what do T lymphocytes do in autoimmunity?
respond to the body’s own cell surface antigens and produce auto-immune disease
what are the two things the two groups of T lymphocyte do?
one group destroys infected cells by inducing apoptosis.
one group releases cytokines, which activate B lymphocytes and phagocytes
what do phagocytes that engulf pathogens do?
display fragments of the pathogens antigens on their surface
what are antigen-presenting cells/what do they do?
activate T lymphocytes, which now to the site of infection guided by the present of cytokines in the area
what can each B lymphocyte clone do?
produces sacrifice antibody molecules, which recognise specific antigens on the surface of a pathogen or toxin
what happens to B lymphocytes do in reference to allergies?
respond to an antigen that is normally harmless
