Introduction to immune responses Flashcards
What important roles, does your immune response carry out?
immune responses are important in defence against infection,
immune responses are important in stopping tumour formation
What are the main physical barriers to infection
Skin, acid in stomach, spermine in sperm, cilia lining trachea, mucus, tears, sebaceous gland secretions, commensal organisms in gut,
What do phagocytes do and where are they generated?
Phagocytes- identify, ingest and destroy pathogens and they are generated in bone marrow
They also produce chemotactic substances that attract other cells to the site
Phagocytes: Macrophages
Microbes must attach to phagocyte, ingestion is then initiated, organism enters the phagocyte in the vacuole and is then destroyed
Phagocytes: Dendritic cells.
Some phagocytes become Dendritic cells and they enter skin and mucus etc, they capture microbes in a process called phagocytosis and eliminate the microbe
Eliminating the microbe is not only task of phagocytic cells, they present these as antigens to T cells
complements help phagocytes to attach and destroy bacteria/organisms
Why is inflammation after an infection beneficial?
Inflammation Attracts cells to the site and helps killing and clearing organisms
Innate immune system
The body’s first line of defence against germs .Natural killer cells play a surveillance role and any cell that has changed is a target for killing.
What makes up the adaptive immune system
B lymphocytes,
T lymphocytes,
Adaptive immune system- high specificity
Where are lymphocytes developed
- Primary lymphoid organs are developed in Bone marrow and Thymus
- Secondary lymphoid organs are the blood, spleen lymph and lymphnodes
Lymphocyte response to antigen
B-lymphocytes recognise antigen through immunoglobin receptors on their surface,
T-lymphocytes recognise antigen through T-cell receptors
The non dividing cells live for years, patrolling-waiting to meet the one or few antigens their receptors bind to
What do B lymphocytes do
B cells make antibodies,
immunoglobulins,
two examples are IGM and IgG
How do Antibodies work
Neutralisation= example- they coat a virus with antibodies to stop it entering cells
Opsonization= They coat micro-organism with anti-body, phagocytic cells have receptor for antibody which means phagocytes can now attach to the bacterium, engulf and then kill
Why does our immune system have a good memory
First time we see an infectious agent we take time to respond,
Second time we meet the same agent-very quick response,
-We remember the enemy this is why we call it adaptive immunity
How do T-cells work
They help B cells make antibodies, How? when activated they release chemicals known as cytokines,
-Cytokines are the helpful chemicals that encourage B cells to work.
What are T cytotoxic cells
-They are cells that kill, they cannot see viruses or bacteria on their own
