Immune system Flashcards
3 pathogen that animals must protect themselves against
viruses, bacteria and fungi
function of the defence system
defend against pathogens
3 things which the general defence system consists of
skin
mucous membranes
phagocytes (white blood cells)
function of skin and mucous membranes
prevent the entry of microbes
function of phagocytes
attack microbes that get into the body
skins physical barrier and function
epidermal cells, prevent the entry of bacteria and fungi
skin secretions and functions
sweat, sebum
are acidic and inhibit growth of microorganisms
what’s in tears and function
lysozome (enzyme) in tears attacks cell wall in bacteria
where are mucous membranes found?
in the respiratory, digestive and reproductive systems
cilia
move the mucous up and out to prevent pathogens from entering the lungs
function of respiratory mucous
thick fluid that traps pathogens
function of digestive mucous
traps microbes
saliva
contains lysozome, an enzyme that kills bacteria
HCl in stomach
kills most microbes in food
function of reproductive system mucous
produces mucous in the vagina to trap microbes
phagocytes
white blood cells
function of phagocytes
the blood cells surround and engulf invading particles and destroy them
the blood cells surround and engulf invading particles and destroy them, what is this called
phagocytosis (like in amoeba)
monocytes
leave the blood and wander around in the body fluids searching for pathogens
what do white blood cells release? what is the result?
chemicals called pyrogens that cause a high temperature to develo throughout the body, fever
what can a fever help to do?
inhibit microbes
2 ways we keep microbes out of the body
skin and its secretions
mucous membrane lnings and their secretions
what do we do to attack microbes that get into the body
phagocytic white blood cells
specific defence system
immune system
what is the immune system capable of doing?
recognising and protecting against particular pathogens
3 main organs of the specific defence system
spleen
thymus gland
lymph nodes
immunity
ability to resist disease
what does the specific immune response depend on?
the production of antibodies by lymphocytes in response to antigens
antigen
a foreign molecule that stimulates the production of antibodies against it
antibodies
defence proteins produced by lymphocytes in response to an antigen
are antibodies specific
yes, each antibody is specific to a particular antigen
PRODUCTION AND ACTION OF ANTIBODIES
first step
lymphocytes recognise a particular antigen and produce a specific antibody against it
PRODUCTION AND ACTION OF ANTIBODIES
step 2
antibodies bind with antigens
PRODUCTION AND ACTION OF ANTIBODIES
step 3
cell with the antigen is then destroyed
PRODUCTION AND ACTION OF ANTIBODIES
final step
antibodies may clump bacteria together and engulfed by phagocytes or antibodies and cause the cell to burst (lysis)
induced immunity
the ability to produce antibodies against specific antigens
2 types of induced immunity
active or passive
active induced immunity
the person produces antibodies and memory cells in response to an infection of invading antigen
what gives long lasting protection
active induced immunity
2 kinds of active induced immunity
natural and artificial
natural active induced immunity
antibodies and memory cells are produced in response to getting and infection eg. flu
artificial active induced immunity
antibodies and memory cells are produced in response to a vaccine
vaccine
a non-harmful dose of a pathogen introduced into the body and it stimulates the production of antibodies and memory cells (future resistance)
passive induced immunity
antibodies produced in another organism are given to the person
natural passive induced immunity
antibodies can pass from mother to child through placenta and in breast milk
artificial passive induced immunity
antibodies produced in another organism are given to the person, immediate immunity
lymphocytes
white blood cells responsible for immunity
2 types of lymphocytes
B cells and T cells
B cells
mature in the bone marrow
T cells
lymphocytes that mature in the thymus gland
where are mature B and T cells usually locates?
lymph nodes, spleen and blood
function of B cells
recognise a particular antigen and produce antibodies against it
what do activated B cells produce
memory cells that live for a long time
Memory B cells
remember the antigen so that if they are exposed to the same antigen again they react quickly giving immediate protection ( and can give long term protection eg.measles)
do T cells produce antibodies?
no
4 types of T cells
helper, killer, suppressor and memory
3 functions of helper T cells
recognise antigens and secrete interferon
they stimulate B cells to produce antibodies
they activate killer T cells
Killer T cells
recognise infected cells and secrete a perforin, perforin causes membranes of infected cells to burst
suppressor T cells
stop the immune response when an antigen is no longer present, they inhibit the production off B and T cells
memory T cells
when exposed to the same antigen that caused their formation they divide rapidly to make new T cells and give immediate protection
