Bio 7D Flashcards
the third line of defence
what is the third line of defence?
a part of the adaptive immune system
- Initiated by the presentation of non-self antigens to specific immune cells of the adaptive immune system
- Comprised of the humoral and cell-mediated responses (form an immunological memory)
what are features of the adaptive immune system?
specificity
- the system responds to each distinct pathogen in a unique and tailored manner
immunological memory
- the system results in the production of cells that allow the body to respond rapidly to future re-infections by a previously encountered pathogen quickly and effectively
what occurs during self-tolerance testing and what does it entail?
B cells and T cells are presented with self-antigens and non-self antigens (attach to the receptor of its surface)
- if they fail, they undergo apoptosis
- if they ‘graduate’, then they become naïve B and T cells
they then migrate to the lymph nodes and wait for an antigen that matches its receptors so they can leap into action
what are T helper cells and how are they selected
- supports the functioning of a number of different immune cells, including the cloning and differentiation of selected T and B cells
- selected through antigen presentation
what are B lymphocytes involved with?
- Involved in antibody production
- Covered in B cell receptors
- Respond to antigens from extracellular pathogens (e.g. bacteria)
- Made from stem cells in bone marrow
- Mature in the bone marrow
what are T lymphocytes involved with?
- Involved with cell mediated immunity
- Eliminate intracellular pathogens and cancer cells
- Mature in the thymus
what is the process of the humoral immune system?
what does the humoral immune system do?
involves the neutralization and/or destruction of a pathogen by B cells producing plasma cells that secrete specific antibodies.
- B lymphocytes travel around the body in the bloodstream and reside in high numbers in the lymph nodes (activation occurs through the interactions with pathogenic antigens and T helper cells)
- targets extracellular pathogens (e.g. bacteria)
