BSC 1086C Lecture Notes - Lecture 6: Natural Killer Cell, Lingual Tonsils, Respiratory Tract
Document Summary
Simplest lymphoid organs: contain follicles with germinal centers, are not fully encapsulated, epithelial tissue overlying tonsil masses invaginates, forming tonsillar crypts that trap and destroy bacteria and particulate matter. Mucosa-associated lymphatic tissue, including: clusters of lymphoid follicles in the wall of the distal portion of the small intestine (cid:523)peyer"s patches(cid:524) and the appendix (cid:523)digestive tract(cid:524, tonsils, lymphoid nodules in the walls of the bronchi (respiratory tract) Protects the digestive and respiratory systems from foreign matter. Immune system has two intrinsic system: innate (nonspecific) defense system. First line of defense- external body membranes (skin and mucosae) Second line of defense- antimicrobial proteins, phagocytes, and other cells. Inflammation is its most important mechanism: adaptive defense system. Third line of defense attacks particular foreign substances. Takes longer to react than the innate system. Surface barriers: skin, mucous membranes, and their secretions. Keratin is resistant to weak acids and bases, bacterial enzymes, and toxins. Lipids in serbum and dermcidin in sweat.
