Search results
Results from the WOW.Com Content Network
The mucosal immune system consists of a cellular component, humoral immunity, and defense mechanisms that prevent the invasion of microorganisms and harmful foreign substances into the body. These defense mechanisms can be divided into physical barriers ( epithelial lining , mucus , cilia function , intestinal peristalsis , etc.) and chemical ...
Several barriers protect organisms from infection, including mechanical, chemical, and biological barriers. The waxy cuticle of most leaves, the exoskeleton of insects, the shells and membranes of externally deposited eggs, and skin are examples of mechanical barriers that are the first line of defense against infection. [8]
The following outline is provided as an overview of and topical guide to concepts related to infectious diseases in humans.. Infection – transmission, entry/invasion after evading/overcoming defense, establishment, and replication of disease-causing microscopic organisms (pathogens) inside a host organism, and the reaction of host tissues to them and to the toxins they produce.
Type III interferons usually act as the first line of defense against viruses at the barriers. [3] [16] In the gastrointestinal tract, both type I and type III interferons are needed to effectively fight reovirus infection. Type III interferons restrict the initial replication of the virus and diminish the shedding of through feces, while type ...
The gut-associated lymphoid tissue lies throughout the intestine, covering an area of approximately 260–300 m 2. [5] In order to increase the surface area for absorption, the intestinal mucosa is made up of finger-like projections (), covered by a monolayer of epithelial cells, which separates the GALT from the lumen intestine and its contents.
Neutrophils are the most abundant type of phagocyte, normally representing 50–60% of the total circulating leukocytes, and are usually the first cells to arrive at the site of an infection. [5] The bone marrow of a normal healthy adult produces more than 100 billion neutrophils per day, and more than 10 times that many per day during acute ...
Intrinsic immunity comprises cellular proteins which are always active and have evolved to block infection by specific viruses or viral taxa. [ 2 ] The recognition of intrinsic immunity as a potent anti-viral defense mechanism is a recent discovery and is not yet discussed in most immunology courses or texts.
In the first line of defense, inhaled bacteria are trapped by mucus and are swept toward the pharynx and are swallowed. [1] Bacteria which penetrate the mucous layer are dealt with a second line of defense which includes antimicrobial peptides that are secreted by the surface epithelium of the respiratory tract which kill many strains of ...