Immunity Flashcards
State 2 differences between a specific and a non-specific defence mechanism.
specific vs non-specific
1. specific pathogens vs all
2. slower vs rapid
Among other places, lysosomes are found in tears.
Suggest a reason why this is so.
- protective covering of eye - thin to allow light through
- vulnerable to infection
- tear ducts = potential entry points for pathogens
What are pathogens?
- disease causing microorganisms
- that trigger an immune response
/ - viruses
- bacteria
- fungi
- protozoa
What are antigens?
- generate immune response when detected by the body
- usually proteins
- on surface of cells
What do antigens allow the immune system to identify?
- pathogens
- abnormal cells (cancerous cells/ tumours)
- toxins (by bacteria)
- foreign **cells from other organisms of same species **(eg. organ transplant)
State 2 similarities between B cells and T cells.
- form of wbc
- produced from stem cells
State 2 differences between T cells and B cells.
- cell-mediated vs humoral immunity
- mature in thymus gland vs bone marrow
What is a macrophage?
- Phagocytic cell
- releases lytic enzymes
- break down pathogenic cells
What do neutrophils do?
- engulf
- digest pathogens
What do phagocytes do?
- engulf pathogens
- destroy them using lysosomes
- then become APCs
Function of APCs
- present pathogenic antigens on cell mem
- signal T-lymphocytes
What do T-helper cells do?
Stimulate:
1. cytotoxic T-cells–> divide & proliferate
2. B-cells–> divide
3. further phagocytosis
4. memory T-cells (immunological memory for future infection)
What do cytotoxic T-cells do?
- kill infected cells
- through release of an enzyme that kills the cell
What are vaccines?
- a way of introducing antigens of a
- dead/ weakened pathogen into the body
- to stimulate production of antibodies & memory cells
State the 4 ways pathogens are made harmless to be used in vaccines.
- killing 🔪but leaving antigens unaffected (eg. cholera)
- weakening (attenuation)🫥- heating🔥 but leaving antigens (eg. oral vaccine against polio)
- purified 😇antigens removed from pathogen (eg. hepatitis B)
- inactivated toxins (toxoids)🤐- harmless but still triggers immune response (eg. Tentanus)