Tri A - Defence and Immunity Flashcards
What are the 2 types of resistance to disease?
Specific and Non-Specific
Describe some physical and chemical barriers of Non-Specific Resistance
Physical: Intact skin,
Mucous membranes,
Hairs in nostrils,
Cilia
Chemical: Lysozyme,
Stomach Acid,
Mucus,
Sweat
What is the function of White Blood Cells?
Rapid defence against infection
What are the 2 main categories of White Blood Cells?
Granulocytes and Agranulocytes
What are the most common White Blood Cells?
Neutrophils: 60-70%
Eosinophils: 2-4%
Basophils: 0.5-1%
Monocytes: 3-8%
Lymphocytes: 20-30%
What is the function of Monocytes?
Enter tissue and become macrophages which phagocytose microbes
Describe the process of Phagocytosis
Phagocytes ingest microbes
They contain granuoles with toxic chemicals
Digestives enzymes break down target once ingested
Describe a Complement and its process
A group of ~20 plasma proteins
1. Complements form holes in bacterial wall and membrane
2. Holes allow fluid and salts to enter
3. Bacterium expands until it bursts
Describe Interferons and their function and process
Non-specific, 1st line of defence
Antiviral proteins produced by body cells
Process:
1. Prevent cell from replicating
and
2. Warn other cells
How is Specific Resistance activated?
- Macrophage digests antigen and breaks it down
- Some bacterial proteins reach surface of macrophage (presenting antigen)
- T-cells with specific receptors recognise antigen
Where do T-cells and B-cells develop Immunocompetence?
T-cell develop immunocompetence in the Thymus
B-cell develop immunocompetence in red marrow
What is the function of Cytotoxic T-cells?
Attack antigens (or possible healthy tissue)
What is the function of Helper T-cells?
Secrete cytokines which attract defence cells.
Also activate B-cells to start making antibodies
What is the function of Regulatory T-cells?
Turn off immune response
What is the function of Memory T-cells?
Remember previous infection and next infection there will be a quicker response
