How do phagocytes protect against pathogens, toxins, cancer cells or foreign tissues?
- The phagocyte is attracted by chemical products of the non-self material, it moves towards the pathogen along a concerntration gradient.
- The phagocyte has receptors that bind to the non self antigens of the material.
- The phagocyte engulfs the material (phagocytosis) and a vesicle known as a phagosome is formed.
- lysosomes within the phagocyte migrate towards the phagosome and fuse with it.
- lysosomes contain hydrolytic enzymes called lyzozymes which hydrolyse the cell walls of the ingested bacteria and destroy it (material digested).
- Soluble products absorbed by cytoplasm. Material debris is absorbed by the phagocyte. Antigens are presented on the surface of the phagocyte.
What is phagocytosis?
When foreign material is ingested by a phagocyte to form a phagosome.
T-Lymphocytes can be one of 2 types. What are they?
T-helper lymphocytes (Th)
Cytotoxic T-Lymphocytes (Tc)
Identify the 2 types of white blood cell.
What are lysozymes?
Hydrolytic enzymes found inside lysosomes that digest foreign material.
What is a phagosome?
A vesicle containing foreign material within a phagocyte that is formed during phagocytosis.
Is phagocytosis a specific or a non-specific response to a non-self antigen?
Are Phagocytes 'antigen presenting cells'?
Yes - they present foreign antigens on their surface after engulfing a foreign material.
Describe how phagocytosis of a virus leads to presentation of its antigens
Phagosome FUSES with lysosome
lysosome contains lyzozymes which destroy virus]
antigen displayed on cell MEMBRANE of phagocyte (APC)
why are lysozymes found in tears?
they protect our eyes from bacterial invaders.