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
