Non-specific responses to disease Flashcards
What are primary defences?
Primary defences are those that attempt to prevent pathogens entering the body.
How is the skin a physical barrier?
Outer layer of skin called the epidermis, most cells are keratinocytes. Migrate from lower epidermis to surface of the skin – dry out cytoplasm on the way, and replaced with protein keratin. Keratinisation – 30 days duration. Dead cells when they reach the surface – acting as a physical barrier.
What are other primary defences?
Mucous membranes found in the gut, genital areas, anus, ears and nose. Eyes protected by antibodies in tears, ear canal lined with wax, vagina with an acidic pH.
What is the structure and function of Neutrophils?
Most common phagocyte, multilobed nucleus, manufactured in the bone marrow, squeeze out of the blood to the tissue fluid, short-lived but in large numbers.
What is the structure and function of Macrophages?
Larger cells produced in the bone marrow, travel in blood as monocytes – settle in body organs, lymph nodes, whereby they develop into macrophages.
How are pathogens recognised as foreign bodies?
Pathogens recognised as foreign by antigens on their surface – flagged as foreign.
What happens with antibodies attach to antigens?
Antibodies attach to foreign antigens – Phagocytes have membrane-bound proteins that act as receptors, receptors bind to antibodies on the pathogen – assisted by opsonins. Phagocytes on the pathogen, envelops pathogen by folding membrane inwards on it – pathogen trapped inside it – lysins, which digest bacteria.
What does infected cells releasing histamine do?
Infected cells release histamine, which attracts neutrophils – makes capillaries leakier. More tissue fluid passes into the lymphatic system – leads pathogens towards macrophages in waiting lymph nodes.
What is the immune response?
Immune response is the activation of lymphocytes to the blood to fight disease.
