MCB Ch 12

Immunity

ability to ward off disease

Innate Immunity

defenses against any pathogen -something we have when we're born or soon after

Urine

flows out

Vaginal Secretions

flows out

Adaptive Immunity

immunity resistance to a specific pathogen -acquired -get it as soon as we've been exposed over a period of our life

Susceptibility

lack of resistance to a disease

Ciliary Escalator

microbes trapped in mucus are transported away from the lungs -always moving up

Explain the steps of successful phagocytosis and pathogen elimination once a macrophage has come into contact with a bacterial pathogen

In phagocytosis, phagocytes are attracted to the area of invasion by chemical products of the microorganism. The phagocyte moves into the area of invasion and then attaches to the microorganism. C3B binds to C3B receptors on the phagocyte. (opsonization) The microorganism is then engulfed by the phagocyte in a vacuole known as a phagosome. Vesicles in the cytoplasm called lysosomes fuze with the phagosome releasing enzymes. into the phagocell. This is now called a phagolysosome. The microorganisms are killed and digested. Finally, the contents of the phagolysosome are eliminated by exocytosis. 1. adherence of microbe to phagocyte 2. ingestion of microbe by phagocyte 3. formation oh phagosome 4. fusion of the phagosome with a lysosome to form a phagolysosome 5. digestion of ingested microbe by enzymes 6. formation of residual body containing indigestible material 7. discharge of waste materials by exocytosis.

Define the functions of neutrophils, macrophages, natural killer cells, and dendritic cells relative to how they help the innate and acquired immune system respond to and eliminate pathogens.

Neutrophils are the most abundant of our white blood cells they make up 60-70% of our WBC's. They are general purpose phagocytes that react early in the inflammatory response to bacteria and other foreign materials and damaged tissue. They are active engulfers and killers of bacteria. They are guided to sites of inflammation within minutes. Macrophages lead the bodies cell mediated immune response by engulfing and digesting foreign invaders. These cells are important in nonspecific phagocytosis, and in regulating, stimulating, and cleaning up after immune responses. Natural killer cells are lymphocytes with no immunological memory. They do not need to recognize specific antigens before releasing their toxins. They have no antigen specificity. They destroy target cells. they are looking for cells that don't have the right antigen or "tag" on it saying it doesn't belong. They target tumor cells, cancer cells, and protect against a wide variety of infectious microbes. They kill on contact. Dendritic cells are antigen presenting cells. They are phagocytes and are capable of attacking cells in our bodies that have become cancerous. They are responsible for processing foreign matter and presenting it to lymphocytes.

How does normal microbiota protect us?

Normal microbiota protects us because it competes with other pathogens to occupy the space so they can't. They also alter the environment to make it inhospitable for other pathogens.

Mucus

traps microorganisms

How can pathogens evade the immune system?

Pathogens evade the immune system through inhibiting adherence (M Proteins, capsules), killing phagocytes (leukocidins), lysing phagocytes (membrane attack complexes), escape phagosome, prevent phagosome-lysosome fusion, survive in phagolysosome

Know physical and chemical and microbiological barriers to pathogens.

Physical -skin -epidermis -lacrimal apparatus -saliva, urine Chemical -fungasitic fatty acid sebum low pH (3-5) of skin low pH (1.2-3.0) of gastric juice lysozyme in perspiration, tears, salive and urine

Lacrimal Apparatus

washes eye

Saliva

washes microbes off

Know how the compliment system works including activation pathways, general cascade, and outcomes.

The complement system involves 30 proteins that circulate in our bodies and protect us against any pathogen. It is part of our immune system. The general cascade has 3 outcomes. Opsonization which allows macrophage to attach, inflammation which brings white blood cells to the affected area, and cytolysis where the membrane attack complex causes the cell to burst. The C3's and C5's cause inflammation while the C3B catalyzes reactions. The activation pathway is the way in which C3's become stimulated to become that cascade. Everything before C3 is the activation pathway. Capsules can prevent C activation. Surface lipid carbohydrates prevent membrane attack complex formation.

Understand how the lymphatic system works

The lymphatic system is a compartmentalized network of vessels, cells, and specialized accessory organ. It begins in the farthest reaches of the tissues as tiny capillaries that transport a special fluid through increasingly larder tributary system of vessels and filters, and leads it to major vessels that drain back into the regular circulatory system. Some of its major functions include: -providing a route for the return of extracellular fluid to the circulatory system -acting as a "drain off" system for inflammatory response -rendering surveillance, recognition, and protection, against foreign materials through a system of lymphocytes, phagocytes, and antibodies.

Understand the process of inflammation

The process of inflammation begins when bacteria on an object (such as a knife) enters the skin. Chemicals like histamine are released by the damaged cells. A blood clot forms so you don't bleed out and then an abscess forms. White blood cells get to the area and line up on the edges of blood vessels.