Bio 310-section 001Midterm exam10/26/14Microbiology II, 1.) Please describe in detail innate immunity. Be sure to be descriptive andinclude all the cells and proteins involved.2.) Please describe in detail adaptive immunity. Though it was not covered inclass, use your PowerPoint and other sources to describe this extensively.Be sure to include information on T cells and B cells.INNATE IMMUNITY
Lunch!A macrophage reaches out witha pseudopod in order to draw in foreign objects. It then envelops and "eats" them, displaying portions of the invaders on its surface for other immune cellsto see and identify.Our second line of defenseThe second line of defense is the innate (or natural) immune system, so-called because all animals are born with it. Innate immunity provides the body with a non-specific defense againstall objects or organisms perceived as being foreign.Should a virus, bacterium, or parasite get past the physical barriers, it is met by the complementproteins, phagocytes, and natural killer cells of the innate immune system.
Complement proteinsThe human liver manufactures around 20 proteins that work together to destroy invaders whichhave gotten past the body's physical barriers. They interact with antigens in one of several ways — either marking them for ingestion by other immune cells, sending out chemical signals to bring additional immune cells to join the fight, or combining together with one another and killing the invaders directly by punching holes them.In this light level photomicrograph,an isolated tingible body macrophage (center) is shown with engulfed, or phagocytized, dead or dying cells (labeled with a brown dye).PhagocytesFrom the Greek phagas, to eat, and kutos, a vessel (or cell), phagocytes are white blood cells which ingest, or eat, harmful foreign particles, bacteria, and dead or dying cells.Phagocytes are divided into professional and non-professional classes. The main difference is that professional phagocytes are almost exclusively involved in eating (phagocytosis), and have special receptors (antenna-like molecules) embedded on their surface that allow them to detectforeign objects not normally found in the body. Professional phagocytes include dendritic cells,
macrophages, mast cells, monocytes, and neutrophils. Of these, macrophages and neutrophils are arguably the most important.MacrophagesMacrophages, or large (macro) eaters (phages), are the sentries of the immune system. Like other white blood cells, they are produced by stem cells in the bone marrow. They are then distributed throughout the body just below the surface of the skin and mucous membranes — anyplace where a pathogen could get through the first line of defense — in order to keep watch.In their normal, resting state, macrophages are the janitors of the body. They spend their time cleaning up body tissues by eating the remains of other cells which have died in the normal course of their life cycles. During this stage, macrophages proliferate slowly.