Defence Mechanisms Flashcards
Immunity
The body is better prepared for the second infection of the same pathogen
What are the 2 defence mechanisms
Non Specific
Specific
What is a specific response
Response is slower and specific to each pathogen
What is a non specific response
Response is immediate and the same for all pathogens
What are the non specific responses
Physical barrier (skin)
Phagocytosis
How are own cells recognised
Each cell contains proteins on its membrane to distinguish itself
Can identify :
Pathogens
Non self material
Toxins
Abnormal body cells
Why are tissue / organ transplants complicated
Immune response will attack transplant
So closest match must be found , immunosuppressant drugs must be used
How lymphocytes recognise cells belonging to body in babies
In fetus, lymphocytes constantly collide with cells
Infection in fetus is rare, protected by placenta
Lymphocytes therefore only collide exclusively with bodies own material
Some lymphocytes have receptors that exactly fit bodies own cells
These lymphocytes either die or are suppressed
Only remaining lymphocytes are those that may fit foreign material
How do lymphocytes recognise cells in body belonging to self in adults
Lymphocytes produced in bone marrow initially only encounter self antigens
Any lymphocytes that show immune response to self antigens undergo cell death (apoptosis) before they can differentiate into nature lymphocytes
No clones of these anti self lymphocytes will appear in blood, leaving only those that will respond to non self antigens
Where are lymphocytes produced
Bone marrow
Where do T lymphocytes mature
Thymus
Where do B lymphocytes mature
Bone marrow
