MCB 2000 Lecture Notes - Lecture 5: Reticular Connective Tissue, Mononuclear Phagocyte System, Lymphatic Vessel
Document Summary
Innate, non-specific: 1st line of defense (anatomical and physiological barriers, 2nd line of defense (cellular and chemical systems, acquired, specific, 3rd line of defense. Naturally acquired: active (infection, passive (maternal antibodies) Artificially acquired: active (vaccination, passive (immune serum) First line of defense: physical factors, skin, mucous membrane, chemical factors, sebum, gastric acid, lysozyme. Skin: skin consists of two layers, epidermis outer thinner portion made of tightly packed cells (upper layer dead cells, dermis inner thicker portion; gives skin strength, infection can develop when the epithelial surface is broken. Mucous membranes: mucous membranes line the gastrointestinal, respiratory and genitourinary tracts, epithelial layer secretes the mucus that maintains the surface of the membrane always moist, mucous membranes are more susceptible to infections than skin. Lacrimal apparatus: provides washing action; removal of microbes, ciliary escalator, the mucus membrane of the lower respiratory tract is covered with cilia; propel mucus containing microorganisms upward.
