Immunity Flashcards
Pathogens
Harmful agents are called pathogens they are biological agents that cause disease or illness to its host
Pathogens include
Bacteria(e coli and sypilis)
Fungi (athletes foot and yeast infections)
Viruses(cold flu and HIV)
Parasites ( crabs live and tapeworms)
Common ways pathogens spread
Airborne
Like the flu or cold are spread from person to person through coughing or sneezing
Water-borne
Water that is contaminated by pathogens and enters the water system
Contaminated food
Food can be contaminated by being stored poorly or by unsafe handling
Direct contact
If you directly touch and infected person or something that person has touched a pathogen might be spread to you
First line of defense
The body’s first line of defence is to prevent pathogens from entering in the first place.
This falls to the physical defences which include
skin protective barrier sweat and oil that are acidic to prevent bacterial growth
Eyelashes and hairs act as a filter
Stomach acid
Mucous
Ear wax
Tears
Cilia in the trachea
Second line of defense
Is called non-specific defense because it is the same regardless of what kind of invader triggers it
This localized condition results in an inflammatory response characterized by
Increased blood flow to the damaged area(blood)
Swelling (blood)
Redness (blood)
Heat (fever) kills bacteria
Macrophages
Means big eater
Macrophages are WBCs that eat dead cells foreign cells and molecules from outside the body (develope from monocytes)
Macrophages function
When a macrophage engulfs or phagocytizes an invader the macrophage will display the invaders antigen marker on its surface this allows to keep a record of the pathogen and it allows the body to respond quicker the next time
Inflammatory response
The inflammatory response begins when a blood vessel is damaged
Mast cells which reside in connective tissue release histamines that causes swelling as blood vessels dilate in the injured area and attract macrophages and neutrophils which both phagoyize bacteria. The macrophages release digestive enzymes which destroy the invader and the marcophage
The remains of the invader and macrophages is called pus.
Third line of defense
The immune response begins when a pathogen gets through the body’s physical barriers so the first line of defense
White blood cells check the identity of every substance encountered in the bloodstream
All cells have special markers located on their cell membranes called antigens
These protein markers provide an identification system that helps your body differentiate between your cells and invaders antigens are like a finger print
T cells
Are an umbrella term for lymphocytes that mature in the thymus glands near heart
In general T cells recognize and destroy invaders and coordinate the immune response T cells seek out invaders that have antigen markers that don’t match the body’s own markers there are different types of T cells with different functions.
Helper T cells
Bind to foreign antigens on the macrophage
Coordinates the immune response by sending out chemical messages to other WBC ( B cells and killer cells)
HIV / AIDS
The HIV virus attacks and kills helper T cells of the immune system resulting in AIDS
Without adequate supply of helper T cells the immune system cannot signal B cells to produce antibodies or killer T cells to kill infected cells
When HIV has destroyed the helper T cell population the body can no longer launch a specific immune response abs becomes susceptible to many other pathogens and cancers
Killer T Cells
Aka cytotoxic cells
Patrol the body looking for cells that have changed due to mutation and could become cancerous
Cells that have been infected with viruses (sometimes other pathogens). These malfunctioning cells display antigens that attract killer T cells
The killer T cells use special chemicals to puncture and destroy infected of malfunctioning cells to prevent spread of a cancer or infection
B Cells
Receive message from the help T cells.
Multiply and produce antibodies that have a complementary shape to the antigens.
Antibodies fit together with and bind with antigens like a lock and key
The antibodies stay in your body after and attack so the next time you encounter the same pathogen your body can respond much faster.
Antibodies
Antigens are markers that distinguish cells and pathogens from one another
Antibodies are “y” shaped proteins that help protect against foreign invaders the body does not produce antibodies that bind to its own antigens therefore all particles that are bound to antibodies are foreign
Antigens attached to cells will cause the cells to agglutinate (clump together
Cells particles or molecules like poisons that are marked with antibodies will be phagocytized by macrophages
Suppressor T cells
Aka regulatory T cells come activated once the threat of infection has passed
Signal the immune system to retire to its pre infection state
When the body has started to wine the battle against the invader the suppressor T cells with slow and suppress the immune response by inhibiting the B cells
