Immune Response Flashcards
What is the body’s first line of defence
The innate immune system
Name some features of the innate immune system
Skin Mucus Cilia Tears/saliva Stomach acid
What is an antigen
A large molecule on the surface of a cell/virus that can be used to determine if the cell/virus is self or non-self
What is the body’s second line of defence
The adaptive immune system
Name some features of the adaptive immune system
Phagocytosis fever Blood clotting Inflammation Natural Killer Cells
How does phagocytosis occur
Dendritic and macrophage cells engulf the pathogen and hold it internally in a vesicle. The then release enzymes to break down the pathogen
What is an opsonin
Any molecule that enhances phagocytosis by marking a antigen for an immune response
How does blood clotting work
Platelets release thromboplastin which turns prothrombin into active thrombin. Thrombin turn Fibrinogen into fibrin fibres which cross over to form a plug
How can blood clotting go wrong
By forming an embolism
What are the symptoms of inflammation
Heat
Swelling
Redness
Pain
Why does inflammation occur
Mast cells and Basophils release histamine which causes vasodilation attracting white blood cells
What is the body’s third line of defence
Specific immunity
Name the features of specific immunity
Humoral immunity
Cell mediated immunity
What happens in antigen presentation
Dendritic and macrophage cells bind to the pathogen and enter the lymph where they present the non-self antigens to specific B and T helper cells
What happens in clonal expansion
The t-helper releases cytokines which causes the B cell to multiply rapidly. Some develop into plasma cells and others become memory cells
How are antibodies produced
The new B plasma cells produce antibodies to attack
the antigen. The antibodies are released into the blood. Antibody-antigen complexes are then destroyed by phagocytes and/or expelled from the body in urine. Remaining B plasma cells and antibodies only remain in the blood for a few weeks.
What happens to the B memory cells
They remain in the lymph to help identify the pathogen more quickly next time there is an infection
List the four ways antibodies work
Clump pathogens together
Neutralise toxins by releasing antitoxins
Digest bacterial enzymes (lysis)
Coat pathogens in protein to label them as foreign
What is cell mediated immunity
T cells are cloned to produce t killer, helper and memory cells. T killer cells locate diseased body cells and kill them to kill the pathogen
What can t helper cells do
Release cytokines to stimulate phagocytosis
What types of immunity are there
Innate - born with it
Acquired
How can you acquire immunity
Actively - exposure to infection, vaccination
Passively - mothers antibodies, injected antibodies
Why are most vaccines given in multiple doses
First dose induces primary immune response but secondary immune response is more effective
How can vaccines be ineffective
On a pathogen that mutates very frequently
They don’t fully stimulate an immune response
Ethical considerations around vaccination
Cost vs efficacy
Protection of the individual compared to herd immunity
The right to autonomy in mandatory programmes
Side effects
