week 7- immune system Flashcards
what are the 3 main components of immune system
-physicial barrier (skin)
-chemical barrier (saliva)
-Callular barrier (lymphocyte)
what is another word for the skin
epidermis
what does the epidermis do to kill unwanted pathogens?
secretes anti-microbial peptides t
it is also an impermeable barrier
what is the role of mucous
to trap invading pathogens
in the ciliated epidermis of the lungs, explain the process of an invading pathogen and its death.
-The ciliated epithelium of the lungs is a ciliated mucous membrane
- the mucous is to trap invading pathogens
-then the cilia (tiny hair-like coating) vibrate to push mucous up to the oesophagus
-it is then swallowed.
give examples of second line of defence
saliva, stomach acid
how can saliva kill pathogens
-contains Lysozymes, which can break down the cell wall of bacteria
- it also contains Immunoglobulin A, which can attach to an invading pathogen and inhibit its function
how can stomach acid kill pathogens
Stomach acid is an extremely low pH, very acidic, which is an inhospitable environment for pathogens and they will die/breakdown/denature in thestomac
describe the inflammatory response in the second line of defence
Injured cells secrete danger signals which cause mast cells to secrete histamines/prostaglandins that cause migration of immune cells to the site of injury
-Capillaries dilate to allow more fluid to the site of injury
-Pyrogens are released which increase temperature
-Pain receptors become activated
-White blood cells (phagocytes) migrate to the site of injury
name signs of second line of defence
-Swelling
-Redness
-HeatPain
-Loss of function (sometimes – depends on locatio
name functions of second line of defence
-Limit the spread of injury/infection
-Prevent further damage
-Dilute or remove harmful agents (Bacteria/Toxins)
-Remove damaged cells, tissue and debris
what is third line of defence
cell-mediated immunity
what does cell mediated immunity involve
the destruction of the bodies infected cells by cytotoxic T cells, and also destruction of pathogens by white blood cells(macrophages/neutrophils)
It also involves the release of cytokines (proteins that signal otherimmune cells
describe antibody mediated immunity
the response to a specific pathogen, it involves the action of T helper cells which after activation with an antigen complement to B-cells
-these will then differentiate into plasma B cells which can produce antibodies against thespecific pathogen.
- These antibodies are released into the bloodstream and circulate around the body in large numbers, they target specific sites on the invading pathogen(antigen) and bind with it to prevent it from infecting cells
what do memory cells allow
quicker response to thepathogen next time it is encountered
what is the concept behind immunisation
prior exposure to an attenuated strain of a virus will allow the body to produce this immune response in a controlled manner, boosting the number of memory B cells that are then primed to respond to that particular pathogen
what are primary organs of the immune system
-bone marrow
-the thymus
name secondary organs of the immune system
-lymph nodes
-spleen
-lymph tissues
-Cutaneous Immune System
what is the Cutaneous Immune System
Cutaneous Immune System,this is where mature lymphocytes can move around the body in order to respond to foreignantigens
What prevents immune cells from killing self cells
Self markers (MHC)
What does a heamotopio stem cell subdivide into
Lymphoid stem cell
myeloid progenitor
How does a virus use a host cell
entering at taking over its replication process to create new virus cells
Describe the cell response occurs once an infected cell has died from a virus (necrosis)
Killed cell will release signals to other cells
- this will stimulate nearby MAST CELLS to DEGRANULATE (release their granules)
- these granules are proinflammatory mediators (histamine) which are chemoattractors (attract immune cells to site of infection)
How do capillaries respond to necrosis (a cell that has died) via virus
-dilate and become more permeable (leaky)
-this will allow more fluid and immune cells to the area
- surrounding tissues swell as proteoglycans hold onto extra fluid
-pressure build up stimulate pain receptors
describe phagocytosis
Phagocyte engulfs invading pathogen into a phagaspme
Lysosomes secrete toxins and hydrolytic enzymes, killing pathogen.
What cells present antigens, why?
Dendrites
Carry them around to find a T cell to take up the antigen
When will a helper T cell become activated
After antigen presentation
Will become T helper cell or cytoxic T cell
What occurs to a cytoxic T cell after activation
will identify infected cell
When identified will perform targeted cell death and kill the infected cell
How is a virus neutralised
Body will be flooded by antibodies against a certain virus
antibody attaché to complimentary binding site on the virus antigen
It can no longer bind and gain access to a host cell
What are B cells programmed to produce
antibodies specific to viral antigens
