MCB 2000 Chapter Notes - Chapter 14: Lysosome, Abdominal Cavity, Blood Vessel
Document Summary
Defense mechanisms of the host: innate, nonspecific. 1st line of defense (anatomical and physiological barriers) 2nd line of defense (cellular and chemical systems: acquired, specific. 3rd line of defense: naturally acquired. 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 secrets the mucus that maintains the surface of the membrane always moist, mucous membranes are more susceptible to infections than skin. 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. Second and third line of defense: immune system. Responsible for: surveillance of the body - white blood cells, they recognize foreign material distinguish between self and nonself , destruction of foreign entities.
