What is the function of monocytes and macrophages?
Ingest and destroy invaders. Present antigens on their surfaces.
What are the functions of natural killer cells?
kill by releasing small cytoplasmic granules that cause the target cell to die by apoptosis.
What is the function of dendritic cells?
Antigen presenting cells. Act as an interface between the innate and adaptive immune systems by activating B and T cells.
What are the innate leucocytes?
Natural killer cells, mast cells, eosinophils, basophils; and the phagocytic cells including macrophages, neutrophils and dendritic cells, and function within the immune system by identifying and eliminating pathogens that might cause infection.
What are the phagocytic cells of the immune system?
How does phagocytosis work?
1. Pathogen binds to phagocyte membrane receptor
(bacteria with capsules must be coated with antibody to bind to phagocyte receptors
The particle becomes surrounded by pseudopods.
A vacuole is formed, containing the particle, and lysosomes digest the particle.
Secretory molecules are released, trigger inflammation.
Tissues response to the presence of a pathogen.
Consists of an innate and an adaptive response.
Triggers of inflammation are:
Macrophages: engulf invaders and display antigens.
Chemotaxins: released by some bacteria and activate phagocytes.
Complement: produces cytokines that trigger other mechanisms.
Lymphocytes: fight infection or control other cells to do so.
After inflammation is triggered:
Phagocyes migrate to the site of infection.
They exit the blood vessels by diapedesis.
Begin digesting and destroying invaders
Produce cytokines to activate the other cells of the immune system
What are the effects of the second step of inflammation?
Blood circulation to the area is increased.
The blood vessels dilate.
Innate and adaptive elements fight against infection until it is eradicated.
What are the four cardinal signs of inflammation?
What is Complement?
A series of plasma proteins which circulate as an inactive form.
Conversion to the active form involves a proteolytic step.
Forms the membrane attack complex.
Bind to microbes, act as opsonins, trigger bacterial cell lysis.