immunity Flashcards
what are pathogens?
pathogens are microorganisms that cause disease
what are the chemical and physical barrier/non-specific response that protect you from pathogens?
- eyes - tears produce enzymes which kill bacteria/ wash out bacteria
- mouth - saliva cleans and removes bacteria
- nose - mucus traps bacteria
- lungs - tiny hairs cilia move mucus to the back of the throat
- stomach - hydrochloric acid kills bacteria
- skin - oil/sebum and dead cells make it difficult for pathogens to enter
- large intestines - bacteria in faeces prevent growth of pathogens
- reproductive system - acid conditions in the vagina prevent growth of pathogens
what is an antigen?
a protein located on the outer surface of cells that triggers the immune response/antibody production?
Antigens are…?
large complex molecules such as proteins, polysaccharides and glycoproteins and also chemical markers
where are antigens found?
the surface of pathogens/abnormal cells/ other organisms of the same species e.g tissues and organs
Why is this a problem with transplants?
the immune system recognises the tissue or organ as non-self eventhough they have come from individuals of the same species. and therefore attempts to destory the transplant
what are self antigens?
antigens on your cells
What are non-self antigens?
antigens which are not on your cells for example Bacteria, viruses or even cell from another human
When pathogens get pass the physica/chemical barrier…?
it causes
1. inflammation
2. Blood clots
3. Phagocytosis
function of white blood cells?
protect the body against infection
How many white blood cells do we produce in a day?
100 billion
Are there fewer rbc or fewer wbc?
for every 1 wbc there is 600 rbc’s
What are white blood cells also referred to as?
leukocytes
Two types of white blood cells?
phagocytes and lymphocytes
Role of phagocytes?
destroy invading microorganism by phagocytosis
Role of lymphocytes?
destroy invaders by producing antibodies
Two types of phagocytes?
neurophils and monocytes
role of Neurophils?
travel in the blood to infected sites where they engulf germs and fungi
Role of Monocytes?
capable of changing into hunting/macro-phages which destroy germs
What is phagocytosis?
the process by which phagocytes engul, ingest and digest pathogens
what type of process is phagocytosis?
non-specific, immediate response
Why is the pathogen not harmful to the phagocytes?
the phagocytes absorbs them
process of phagocytosis?
the phagocyte will recognise the antigen on the membrane of the pathogen as non-self
the phagocyte will engulf the pathogen so go through phagocytosis. The pathogen is wrapped in a membrane sac called a phagosome.
lysosome (vesicles containing digestive enzymes) move towards the phagosome containing the pathogen
the lysosome will fuse with the and lysozymes enzyme is released into it. this is called a phagolysome.
the enzyme hydrolyses the pathogen and kills it. harmless products of digestion are absorbed by the phagocyte.
what is antigen presenting?
The phagocytes sticks The antigens to its surface to activate the immune systems white blood cells
How do we minimise the effect of tissue rejection?
donor tissues is matched as closely as possible/ immunosuppressant drugs are administered
what type of cells does cellular immunity involve?
where do these cells mature in?
t- cells - mature in the thymus gland
Process of cell-mediated immunity?
pathogens invade body cells and are taken in by phagocytes
the phagocyte places antigens from the pathogen on its cell surface membrane and presents it to a t-cell
receptors on a specific helper T cell fit exactly onto the antigens as they are complimentary to antigen
the attachment activated the T helper cell to divide rapidly by mitosis and form a clone of genetically identical cells
After this the cloned T cells…?
develop into memory cells
stimulate phagocytosis
stimulate B cells to divide and secrete their antibody
activate cytotoxic cell