Immune System Flashcards
Name the two defense systems of the immune system
Nonspecific defense
Specific defense
Nonspecific defense (simple explanation)
- protects the body from all foreign invaders, regardless of their type or location
- mechanical barriers
Types of Nonspecific defenses (4)
- skin
- mucous membranes
- inflammatory response
- proteins
Skin (characteristics)
- unbroken skin = physical barrier to most microbes
- sweat + sebum (oil) = acidic to inhibit bacterial growth
- sebum also contains antibacterial compounds
(1st line of defence)
Mucous membranes (characteristics)
- physical barrier in all body cavities that open to the exterior
- some are ciliated to sweep foreign particles away
- some secrete acids or enzymes to inhibit bacterial growth
(1st line of defence)
Specific defense (simple explanation)
- the immune system
- involves specially formulated substances that attack specific antigens the body has come into contact with previously
Innate immunity
1st and 2nd line of defence
second line of defence
general couple of cells that still attack an invader that gets passed 1st line of defence
second line defence (examples)
cells and chemicals:
- phagocytosis
- natural killer cells
- inflammatory response
phagocytic cells
phagocytic cells are specialized white blood cells such as macrophages or neutrophils that engulf foreign particles and destroy them
natural killer cells
natural killer cells are a type of lymphocyte that blinds to certain tumor cells and virus-infected cells and kills them by injecting granules that contain special protein such as perforin, which creates hole in the plasma membrane
inflammatory response
- triggered by injury to body tissues
- damage cells release chemicals (histamine +kinins)
symptoms of inflammatory response
1) redness
2) heat
3) swelling
4) pain
5) loss of function (cant move etc)
1st line of defence (examples)
- skin
- mucous membranes
inflammatory chemical causes
1) blood vessels dilate = increasing blood flow to the damaged areas = leads to redness + heat
2) capillaries become leaky = allows plasma into tissues = leads to swelling
what does inflammatory chemicals also activate
pain receptors
- swelling increases pain by putting pressure on nerves
- pain and swelling can lead to loss of function
- pain alerts you to damage in the body do you don’t further injure yourself
white blood cells (such as phagocytes) are attracted to what?
attracted to damaged area by inflammatory chemicals
chemotaxis
the movement of cells towards or away from a chemical stimulus
diapedesis
the movement of white blood cells through capillary walls into tissues
neutrophils
drawn to damaged area by inflammatory chemicals, followed by monocytes
purpose of inflammatory response (4)
1) isolates foreign substances from other body tissues
2) phagocytic action of WBC’s disposes of cell debris and pathogens
3) prepares the area for repair
4) clotting proteins in the body initiate the formation of a fibrin net which seals off the damaged area and prepares the way for tissue repair
describe fever
- abnormally high body temperature
- systemic response to to invading microbes
how does fever benefit the body (2)
1) limiting the ability of bacteria to multiply
2) speeding up metabolic processes such as tissue repair
adaptive immunity
3rd line of defence: specific defense characteristics
- antigen-specific
- systemic
- has memory
- two divisions: humoral & cellular
describe what the immune system does to antigens
antigens = foreign invaders
the immune system works to destroy or inactivate them
it is specific systemic and it remembers previous encounters with pathogens
describe humoral
1) also called antibody-mediated immunity
2) employs antibodies in body fluids
describe cellular
1) also called cell-mediated immunity
2) uses living cells (lyphocytes) to destroy infected cells either directly or indirectly
describe antigens + examples
antigens are substances that trigger an immune response
ex: bacterium, fungus, virus, toxin, or foreign body
describe protein + its role
- they are strong against antigens
- our cells have protein in the plasma membrane
- some of these protein act as self-antigens which allow our immune system to recognize cells that belong to us and those that do not
how does the immune system respond to antigens
1) producing cells that attack them directly
2) producing specialized proteins called antibodies that bind to them, tagging them for destruction by other cells (each antibody has a protein that is specific to one antigen)
what are the two main cell populations that provide immunity
1) lymphocytes
2) macrophages
what are the two main types of lymphocytes
1) B Cells
2) T Cells
describe B Cells
- produce antibodies and oversee humoral immunity
- develop in bone marrow
describe T Cells
- non-antibody producing lymphocytes
- function in cell-mediated immunity
- develop in the thymus gland
how many types of antigen receptors are on a lymphocytes surface + what is it for
one
- it is specifically designed to react to one distinct antigen
macrophages: where + how do they function
where: in both nonspecific and specific immunity
how: when they engulf particles, they bear those proteins on their plasma membrane to attract T Cells
describe humoral immune response
1) involves antibodies that circulate in the blood or lymph
2) activated when B cell antibodies bind to antigens on the surface of a pathogen
3) triggers rapid division called clonal selection
explain how clonal selection occurs
occurs when activated B cells produce a larger number of clones
most develop into plasma cells which will
produce antibodies until they die in a few weeks or months, but some develop into memory B cells that remain in the body to fight the antigen more quickly and efficiently if it ever returns
describe secondary humoral response
secondary humoral response is the second time a foreign substance invades the body and is met with a swift and effective response from the memory B cells
describe how active immunity is acquired + other info
- acquired during an infection or vaccination
- provides immunological memory
describe how passive immunity is acquired + other info
- acquired when a mother’s antibodies cross the placenta to the baby or when antibodies from a donor are injected
- it is short-lived immunity that does not provide immunological memory
describe antibodies
- proteins produced by B cells / plasma cells in response to an antigen
- they form a T or Y shape with a variable region and a constant region
functions of antibodies (3)
1) complement fixation (attachment signals immune system to attack it)
2) neutralization (antibody attachment blocks the pathogen cells from functioning)
3) —- i have to go eat breakfast brb
