Defence Mechanisms Flashcards
How does a body protect itself from pathogens
Skin - forming a barrier to the entry of pathogens and phagocytosis
- cell mediated responses involving t lymphocytes
- humoral responses involving B lymphocytes
Each type of cell, self or non self, had specific molecules on its surface why are proteins most important
They have enormous variety and a highly specific tertiary structure
This variety of 3D structure that distinguishes one cell from another
What do proteins on the surface usually identify
Pathogens
Non self material
Toxins
Abnormal body cells
Why does a donor tissue for transplant need to be very similar
To minimise effect of tissue rejection, best matches are usually relatives
Immunosuppressant drugs are often administered to reduce the level of the immune response that still occurs
What are the 2 defence mechanisms explain them and give an example
Non specific- response is immediate and the same for all pathogens e.g. physical barrier(skin) and phagocytosis
Specific - response is slower and specific to the pathogen. E.g. cell mediated response ( t lymphocytes) and humoral response ( b lymphocytes)
What happens to lymphocytes that have receptors that exactly fit those of the body’s own cells
They either die or are suppressed
Where are lymphocytes produced
In the bone marrow
After a pathogen gains entry to the body it is often a number of days before the body’s immune system begins to control it. Suggest a possible reason why this is so.
The lymphocytes they will finally control the pathogen need to build up their numbers and this takes time
Suggest why it would be inaccurate that say that the body takes days to respond to the pathogen
The body responds immediately by recognising the pathogen, the delay is in building up numbers of lymphocytes and therefore controlling the pathogen
Pathogen definition
Microorganism that causes disease
Antigen definition
A glycoprotein that triggers an immune response by lymphocytes
