Immune System Flashcards
What are the different types of pathogens?
Viruses Bacteria Parasites Fungus & yeasts Prions
What does the immune system do?
Defence against disease-producing agents (pathogens)
What are the properties of a virus?
Infectious particles, rather than living cells.
Cannot replicate on their own but must hijack the hosts genetic machinery.
What can a virus not do?
Replicate on its own.
What are the properties of a bacteria?
Multiply quickly
True living cells,
larger and more highly organised than viruses.
Can multiply outside the host cell. (Binary fission)
They grow rapidly, dividing roughly once every 20 minutes in ideal conditions.
What is the process of the bacteria multiplying outside the cell called?
Binary fission
In ideal conditions how rapidly does bacteria grow?
Divide roughly once every 20 minutes
Parasites can be be put into 2 categories. What are they?
Single-celled (protozoa)
Multicellular (helminths)
Where are single-celled (protozoa) parasites found?
Live freely in soil or water.
Can u name any parasitic single celled diseases?
Malaria
Amoebic dysentery
Giardia (affects small intestine)
Where are multicellular (helminths) parasites found?
Inhabit the guts of animals
How are multicellular parasites transmitted?
Faeces or ingestion
Can you name any multicellular (helminth) parasites?
Roundworm
Tapeworm
Threadworm
Liver fluke
What are the properties of yeast & fungi?
Cause diseases known collectively as mycoses.
Why are mycoses important in people with compromised immune systems?
Cause “opportunistic infections”
Give an example of an opportunistic infection?
Oral thrush (candida)
What are prions?
Abnormal proteins
What conditions can prions cause?
CJD (creutzfeld-Jacob disease)
CJDv (new variant CJD)
Kuru
What is the immune systems second line of defence?
Blood & lymph
When would the immune systems second line of defence be recruited?
If pathogens breach the physical & chemical defences.
What is involved in the second line of defence in its simplest form?
Huge array of blood cells & circulating proteins
What 2 components is the human immune system divided into?
Natural (innate) immune system
Adaptive immune system
What is the immune systems first line of defence?
Physical & chemical defence mechanisms.
Skin
Natural orifices in the skin posses additional protective strategies
Name some additional protective strategies of some of the orifices of the skin?
Mucociliary epithelium of upper airway
Acid pH of vaginal secretions
Tear fluid of the eyes
What makes up the natural (innate) immune system?
Variety of white blood cells & many proteins.
What white blood cells are included in the natural (innate) immune system?
Natural killer cells Basophils Mast cells Neutrophils Macrophages Eosinophils
Describe the innate immune system?
It is evolutionary “old”, is non-specific and has no memory.
What makes up the adaptive immune system?
Lymphocytes (T-cells & B-cells)
Describe the adaptive immune system?
Evolutionary “new”, recognises specific foreign proteins (antigens or pathogens), and has a memory to a disease once we have fought it off
Why does the immune system carry unique protein markets?
Act as a personal signature (self)
What happens to cells possessing the signature self?
Ignored by the immune system
What happens to anything without the self signature (not-self)?
Viewed as foreign & will be attacked by the immune system
What are some of the proteins of the natural immune system measured for?
Inflammatory diseases (e.g rheumatoid arthritis)
What do mast cells & basophils secrete in response to injury or infection?
Histamine
What do natural killer cells secrete?
Non-specific cytotoxins
What are neutrophils, monocytes & macrophages & what do they do?
Phagocytes
Clean up debris
What do macrophages also secrete?
Pyrogens
What do pyrogens do?
Raise temperature
What is the purpose of a dendritic cells?
Present antigens (pathogen proteins) to the lymphocytes
Where do T & B lymphocytes originate?
Bone marrow
Where do B- lymphocytes mature?
Bone marrow
Where do T-lymphocytes mature?
Thymus gland
What releases lymphocytes into the blood?
Lymphatic system
Where do lymphocytes particularly accumulate?
Lymph nodes & other lymphatic tissue
What do B & T-lymphocytes recognise?
Foreign antigens (pathogens)
How many B& T- cells are capable of recognising each pathogens?
Only a few
What happens after B & T cells recognise an antigen (pathogen)
Form B-cell & T-cell clones (clonal proliferation)
What is the name of the B & T cell cloning process?
Clonal proliferation
What do B & T- lymphocytes do after clonal proliferation?
Differentiate into cells specialised to perform particular roles
What is the function of a T-cell?
Some T-cells are cytotoxic t-cells & go to the site of infection & destroy pathogens using specific toxins.
Others act as helper cells
What is the function of B-cells?
Act at a distance from site of infection.
Secrete specific antibodies that can stick to the pathogen & destroy it.
What happens to the lymphocytes once the disease is wiped out?
Mist of the lymphocytes die.
A few B & T-cells remain as memory cells
What do memory cells give us?
Immunity
How do vaccines work?
Designed to convince the body’s adaptive immune system to mount an immune response without the person becoming seriously ill.
Body will generate memory cells.
What does creating a vaccination involve?
Manufacturing an attenuated form of the pathogen.
Modified so that it is still recognised by the immune system but is not longer highly pathogenic.
The body generates memory cells in the usual way.
