BIOL 2010U Lecture Notes - Lecture 5: Natural Killer Cell, B-Cell Receptor, Cytotoxic T Cell
Document Summary
The immune system recognizes foreign bodies and produces immune cells and proteins. Innate immunity is present before exposure to pathogens and is efecive from the ime of birth. It consists of external barriers and internal cellular and chemical defenses: acquired immunity develops ater exposure to pathogens. It involves a very speciic response to pathogens. Concept 1: in innate immunity, recogniion and response rely on traits common to groups of pathogens. Both invertebrates and vertebrates depend on innate immunity to ight infecion, and vertebrates also develop acquired immune defenses. In insects an exoskeleton made of chiin forms the irst barrier to pathogens. The digesive system is protected by low ph and lysozyme. Lysozyme an enzyme that digests microbial cell walls. Hemocytes circulate within hemolymph and carry out phagocytosis. Phagocytosis the ingesion of foreign substances including bacteria to protect the body. Hemocytes also secrete animicrobial pepides that disrupt that plasma membranes of bacteria.
