Immunity Flashcards
1- what is immunity?
The capability of multicellular organisms to protect the self from harmful microorganisms
The body has a wide array of defence mechanisms
Works against pathogens, viruses, diseases, bacteria, foreign cells and parasites
1- what two branches is immunity split into?
Specific and non-specific
1- what is non-specific immunity?
Mechanisms protecting against a wide range of dangers, not just one
Present at birth
1- is non-specific immunity innate or adaptive?
Innate
1- what are the five main non-specific defences?
1- epithelial barriers
2- phagocytosis
3- natural antimicrobial substances
4- inflammatory
5- immunological surveillance
1- what are the first line defences in non-specific immunity?
=first line defences prevent initial entry
Epithelial barriers and secretions
1- what are the second line defences in non-specific immunity?
= second line defences attack once the danger has entered the bodily
Antimicrobial substances
Inflammatory
Immunological surveillance
Phagocytosis
1- describe epithelial barriers as a non-specific defence
Epithelial barriers
-skin and mucous membranes
Skin- healthy
Nose hair- filters respiratory tract
Cilia- moves mucous and any foreign inhaled materials to throat (coughed or swallowed)
Epithelial secretions
-antibacterial, acidic, antibodies and enzymes
Sweat- antibacterial
Urine- one way flow form the bladder
Vaginal discharge- regularly cleans the vagina
1- describe anti-microbial substances as a non-specific defence
Saliva- washes away food debris preventing growth of bacteria, antibodies neutralise acid that creates tooth decay
Lysozymes- in tears, antibacterial enzymes
Hydrochloride acid- gastric juice
Antibodies- protective proteins on membrane, inactivate bacteria
1- describe phagocytosis as a non-specific defence
Phagocytosis= cell eating
E.g. neutrophils and macrophages
Migrate to infection sites as they are attracted to the chemicals that invading microbes release
Attack, invade and destroy
May release a toxic chemical
Neutrophils- short lived as the toxins they release kill them self too
Macrophages- live longer and link with specific immunity
1- describe inflammatory as a non-specific defence
Inflammatory= physiological response to tissue damage
“-itis”
Purpose- indicate, inactivate and remove invasion or damage to allow for healing
Signs- redness, heat, swelling and pain
Triggers if inflammatory response- pH, heat, foreign bodies
What happens- blood flow (more oxygen to the area) fluid (capillary walls more permeable) temp increase (inhibits growth and division), pain (encourages protection) and pus (collection of material)
Substances released- histamine and serotonin
1- describe immunological surveillance as a non-specific defence
Natural Killer (NK) Cells
=a non-selective lymphocyte (WBC)
Patrol body to search for abnormal host cells
Cells with virus or mutations display unusual markers on their membranes which are detected by the NK cells
Once detected, the host cell is immediately killed by NK cells
2- what is specific immunity?
Mechanisms directed against one specific type of invader
Body ‘learns’ and ‘remembers’ the antigen, therefore creating an immunological memory
Adaptive (as it is learned and not present at birth)
They are activated when the non-specific immune defences get overwhelmed
2- what types of lymphocytes are involved in specific immunity?
B lymphocytes and T lymphocytes
2- what three mechanisms affect the outcome of specific immunity?
Specificity- only targets one antigen
Memory- immunological memory, happens again the response is faster and more powerful
Tolerance- doesn’t attack it’s own cells
2- Describe the role of lymphocytes in specific immunity
= 20-30% of circulating WBCs
Most in lymphatic tissues, not the bloodstream
Include: NK cells, T cells, B cells
All cells carry antigen recognition molecules, only responding to one specific antigen
Range of antigen recognition molecules is predetermined by genetics
Healthy immune system… creates a population of millions of different T and B cells
2- describe the role of T cells in specific immunity
Immature T cells in bone marrow
Migrate to thymus gland
Mature with hormone stimulation
Become specialised
Fully activated when they encounter infected tissues
Circulate to all organs
Programmed to only respond to that specific infection
2- describe the role of B cells in specific immunity
Immature B cells in bone marrow
Stay in bone marrow to mature
Produce antibodies (immunoglobulins)
Immunoglobulins= proteins that bind to and destroy antigens
Only targets one specific antigen
3- what is an antigen?
A foreign substance that enters your body
3- what is an antibody?
A protein produces by your immune system that attacks antigens not wanted in the body
4- describe humoral immunity (with reference to T and B lymphocytes)
B cells!
Don’t have to be presented with the antigen with APC, instead they recognise and bind antigen particles directly
B cells MAKE antibodies
Helper T cells enable B cells to enlarge and proliferate
Then become 2 types of B cells: Memory B cells and Plasma cells
2 types:
Memory B cells= long term immunity for that antigen
Plasma cell= produce antibodies that bind to and destroy that antigen
5- describe cell-mediated immunity (with reference to T and B lymphocytes)
T cells!
Encounter antigen first time and become sensitised to it
Can’t detect free antigen in body fluids
Antigen presenting cells (APC)= T cells need to recognise the antigen on membrane if another cell
4 types of T cells:
Cytotoxic= inactivates by releasing toxins
Helper= stimulate B cells to produce antibodies and helps with cytotoxic response
Regulatory= turn off activated T and B cells
Memory= rapid response to previously encountered
6- how many different antibodies does the body have? What are they called?
5 different antibodies
IgA
IgD
IgE
IgG
IgM
6- what can antibodies also be called?
Immunoglobulins
6- what are the major functions of antibody IgA?
E.g. breast milk
Coats epithelial membranes
Prevents antigens crossing membranes and invading
6- what are the major functions of antibody IgD?
Made by B cells and displayed in B cell surfaces
Antigens bing to IgD and activate the B cells
6- what are the major functions of antibody IgE?
E.g. allergy
Found in cell membranes, binds to antigen, activates inflammatory response
6- what are the major functions of antibody IgG?
Attacks many different pathogens and crosses placenta
6- what are the major functions of antibody IgM?
Short lived
Appear first
Sign of recent invasion
What acronym is used to describe the 5 types of antibodies?
MADGE
