The Immune System Flashcards
What is non-specific immunity and its defences?
Mechanisms that protect against a wide range of pathogens, present from birth.
1st line of defence
Epithelial barriers: skin, nose hair, cilia prevent things entering
Epithelial secretions: oral, vaginal, gastric anti-bacterial and acidic. Sebum and sweat antibacterial and antifungal properties
2nd line defense
Antimicrobial substances: saliva, lysosome, hydrochloride acid, antibodies,
3rd line
Phagocytosis neutrophilsshort lived and destroy themselves with their toxic chemicals, macrophages undergo phagocytosis too but then become Antigen Presenting Cell triggering T cells.
4th line
Inflammatory response: increased blood flow (arteriolar dilate), accumulation of tissue fluid, migration of leucocytes(blood thickens so flow slower allows WBC to adhere to vessel wall and migrate), increased core temp, pain, suppuration (pus/gathering of all dead cells).
What is chemotaxis?
The movement of cells due to chemical messages eg WBC for immune system
What are the five types of non specific defense?
- Epithelial barriers
- Antimicrobial substances
- Phagocytosis
- Inflammatory response
Immunological surveillance (natural killer cells)
What is specific immunity
Involves T and B lymphocytes and is targeted to one antigen. A memory of it is created so the next encounter with pathogen is faster and more powerful. Doesn’t attack own cells.
Process of T lymphocytes
Made in bone marrow and mature in thymus with help of thymosin.
Recognise only one type of antigen can only detect antigen when in a cell not body fluids, so when macrophage is APC, helper cells produce cytokines stimulating B lymphocytes. T killer cells release proliferin (powerful toxins), T regulatory stops immune response, T memory responds quick to new encounters with same antigen.
Process of B lymphocytes
Made and mature in bone marrow
B cells recognise antigen particles directly and make antibodies, T helper cells enable B cell to enlarge and proliferate
Memory B cells provide immunity for antigen
Plasma cell produce antibodies to destroy antigen
Describe function of diff types of antibodies (IgA, IgD, IgE, IgG, IgM) MADGE
IgA: found in breastmilk effective against digestive tract pathogens
IgD: antigens bind here to activate B cells
In E: activates inflammatory response binds to antigen found in excess allergy
IgG: attack many diff pathogens longest lived
IgM: sign of recent invasion short lived
Structure of antibodies
Two heavy chains (made of amino acids) two light chains (made of polypeptide) chains linked by disulphide bonds
What are the types of immunity?
Active: produced own antibodies from invasion of pathogen memory cells formed
Passive: individual given antibodies produced by someone else
Natural: body stimulated,aged to produce antibody by having disease
Artificial: response of attenuated pathogens administered to person and antibodies for pathogen injected into recipient,
What is Anti D immunoglobulin response and how to stop it
Mom rhesus neg baby rhesus pos, placenta damaged blood of baby and mum mix. Mum body makes antibodies against baby blood, next pregnancy if baby rhesus pos mum antibodies attack baby can cause fetal anaemia, haemolytic disease or is fatal.
To stop it anti D immunoglobulin is injected to mum to prevent immune response and kills baby blood in mum but leaves fetus in placenta unharmed.
Lymphatic system and immunity
Lymph system maintains fluid balance returns tissue fluid into venous blood stream, contains lymphocytes, fluid passes through several nodes before being filtered (cleared of foreign material) and returned to circulatory sytstem..
Tonsils! Forms protective ring in the mouth back of throat helps prevent invasion of pathogen between nasal and oral cavities.
Thymus: above the heart T lymphocytes matured here, thymosin (hormone) enables th is
Spleen: as blood passes macrophages that line these venous spaces remove microorganisms from blood and destroy (via phagocytosis)
