2 - Immunity Flashcards
Phagocytes
Stored and produced in bone marrow
Remove dead cells and microorganisms through phagocytosis
Non-specific, first line of defense
Two types:
-Neutrophils
-Macrophages
Phagocytosis
Phagocyte attracted by chemical substance released by pathogen
Pathogen engulfed
Pathogen enclosed in vesicles
Lysosome empties contents into vesicle
Releasing enzymes that hydrolyse bacteria
T - Lymphocytes
Produced in bone marrow, mature in thymus
Have T cell receptors that are specific to one antigen
Activated when they bind to an antigen presenting cell (clonal selection)
Once activated, they divide by mitosis (clonal expansion)
Differentiate into two types of T Cells:
1) Helper T Cells
-Release cytokines that stimulate
other immune cells
2) T Killer Cells
-Recognise and kill infected/
abnormal cells by inducing aptosis
B Lymphocytes
Remain in bone marrow until they mature
When mature, they spread through body, concentrated in lymph nodes and spleen
When mature, each type of B cell makes one type of antibody
When it recognises and binds to antigen, they divide and differentiate into two main types of cells
1) Plasma Cells
Produce antibodies with a
complementary shape to antigen
2) Memory Cells
Remain in bloodstream in case
reinfection occurs in which case they
rapidly divide into plasma cells
Antigen
Glycoprotein receptor on cell surface used to signal an immune response
Vaccine
deliberate introduction of an weakened
pathogen to cause an immune response
active artificial
how do pathogens cause disease
damaging cells
producing toxins
Cellular immune response
includes phagocytosis and T-cell response
Humoral immune response
includes B-cells and the antibodies they produce
Active vs Passive immunity
Active involves memory cells, passive does not
Passive involves antibody introduced into body from outside
Active long term, because antibody produced in response to antigen
Passive short term, because antibody is broken down
Active can take time to develop work, passive fast acting.
