Non-Specific Defences Flashcards
What is a pathogen
Bacterium, virus or other organism that can cause disease
What is immunity
Immunity is the ability of the human body to resist infection by a pathogen or to destroy the organism if it succeeds in invading and infecting the bodyz
How do epithelial cells protect the body
They form a physical barrier. Closely packed epithelial cells are found in the skin and inner linings of the digestive and respiratory systems
Name the types of chemical secretions
Tears, saliva, mucus and stomach acid
How to tears and saliva protect the body
They contain lysozyme to digest cells walls of bacteria
How does mucus protect the body
Cells in mucous membranes secrete sticky mucus to trap microbes which are swept up and away from the lungs by cilia and destroyed by stomach acid once swallowed.
aWhat do mast cells release
Histamine
What does histamine cause
Vasodilation of arterioles and increased permeability of capillaries
What happens in the inflammatory response after vasodilation and permeability
Increased blood flow leads to accumulation of blood-clotting factors at the injured area. Blood clotting (coagulation) prevents blood loss and marks the start of tissues repair.
Aside from blood clotting, what else does increased blood flow cause
An accumulation of phagocytes at the site of injury. The phagocytes complete phagocytosis
What do phagocytes release and why
Cytokines - Act as signal molecules to attract more phagocytes to the site of incection
How do phagocytes destroy pathogens
Phagocytosis
Describe the process of phagocytosis
Phagocyte detects pathogen. Phagocyte engulfs pathogen in a vacuole. Lysosomes fuse with vacuole. Lysosomes release digestive enzymes. Bacteria is destroyed by digestive enzymes.
