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at the onset of a fever, people often has chills. what causes this?
- chemicals released from inflammation travel to the hypothalamus where they stimulate the production of localized hormones called prostaglandins.
- these cause the hypothalamus to turn up its thermostat (fever).
- blood flowing to the hypothalamus (at normal body temperature) now feels cold to the hypothalamus so it also initiates heat gaining actions- shivering.
at the end of febrile illness, people often has diaphoresis, variously called a crisis or breaking a fever or defervescene. what causes this?
- once the infection is under control, inflammatory chemicals are no longer produced.
- the hypothalamus turns its thermostat back down
- now blood flowing to the hypothalamus (at the fever temperature) feels too hot, it initiates heat losing mechanisms - sweating
people often treat fever with aspirin, tylenol, or motrin. how doe these work?
block production of prostaglandins (cause pain especially in smooth muscles)
what is interferon?
- a chemical produced by cells that are infected by a virus.
- signals the cells in the area so they can prepare defense against being infected themselves a
- signals immune cells that it it diseased and needs to be killed
what is the complement system?
- a series of proteins that circulate in the blood in inactive form.
- an infection activates them and they can attach to a bacertia to make it more visible to the immune cells or they can directly destroy some bacteria
when a cell is born, it has marker proteins on its surface that say "this is me". during its life it must continue to reassure they immune system by making new marker proteins that carry molecules from inside the cell to say "this is still me". these new marker proteins are called ______.
what are the two types of lymphocytes involved in specific immunity?
what are the two division of specific immunity?
- humoral-invaders outside of the cells
- cell-mediated- invaders inside the cells
what is the principal agent in humoral immunity?
antibodies or immunogloblins
describe (principal agent humoral) formation
- A b lymphocyte binds to an antigen it finds in the body (but outside of the cell)
- goes to the spleen or lymph node and presents this antigen to a T helper cell
- if the T helper cell decides the antigen is foreign, it release a chemical that cause the b cell to clone
- most of the cells of the clone will turn into plasma cells, which will produce thousands of copies of an antibody designed specifically to bind to the original antigen
what other B cells result from the cloning?
- B memory cells
- these do not take part in the present immune response but remember it
they hang around from years waiting for that antigen to show its ugly head again
first exposure to an antigen until leaks production of antibodies can take two weeks
with B memory cells, peak production can occur in two days
what happens in cell mediated immunity?
some of APC (macrophage, dendritic cell) present an antigen to a T helper cell
T helper cell releases a chemical that causes itself to clone, making more T helper cells
- T memory cells and (more to the point) T cytotoixc cells or T killer cells
- T cytotoixic cells find cells that are displaying the antigen and kill them
- antibodies are not involved in the cell mediated immunity
do the second and third lines of defense interact?
- they do
- natural killer cells and macrophages destroy cells displaying foreign antigens
although they don't need a T helper to activated them, the chemicals released by the T helper cell make them more aggressive and cause them to migrate to areas of infection
what is common to humoral, cell mediated and non specific immunity?
T helper cells
what cells does HIV infection kill?
T helper cells
what does this means in terms of your ability to resist infection?
you don't have any
what are examples of the four types of acquired immunity?
natural active- having the disease and recovering from it
natural passive- antibodies formed by the mother passed to the baby through the placenta or by breast feeding
artificial active- vaccinations
artificial passive- receiving antibodies formed outside the body