Immune System Flashcards
The immune system protects against assaults on the body. Including external assaults and internal assaults. External assaults are:
microorganisms - protozoans, bacteria, and viruses
The immune system protects against assaults on the body. Including external assaults and internal assaults. Internal assaults are:
abnormal cells that reproduce and form tumors that may become cancerous and spread
a protein marker on the surface of cells to identify them. They stimulate the production of antibodies
antigens
the ability to activate an effective response to a foreign antigen
immunocompetence
molecules on the surface of human cells that are unique to an individual, thus identifying the cells as “self” to the immune system
self markers
molecules on the surface of foreign or abnormal cells or particles that identify the particle as “non-self” to the immune system
non-self markers
the ability of our immune system to attack abnormal or foreign cells, but spare our own normal cells
self-tolerance
2 major categories of immune mechanisms:
innate/nonspecfic immunity adaptive/specific immunity
- immunity that is present at birth - built in and ready fr action providing the initial defense mechanism
innate immunity/ nonspecific
- mechanisms that develop in response to specific threatening agents or specific abnormal cells
adaptive immunity/specific
broad and loose category of small proteins that are important in cell signaling - they are released by cells and affect the behavior of other cells or the cells that release them - they regulate or initiate innate or adaptive immunity
cytokines
examples of cytokines:
- interleukins - leukotrienes - interferons - growth factors
7 components of innate immunity
- epithelial barrier cells - inflammation - phagocytic cells - natural killer cells - interferon - complement - toll-like receptors
innate immunity: first line of defense
skin and mucous membranes - sebum, mucus, enzymes, and hydrochloric acid in stomach
innate immunity: second line of defense
inflammatory response
tissue damage leads to release of inflammation mediators (histamine, kinins, prostaglandins, leukotrienes, and interleukins) many of these mediators are chemotactic factors: subtances that attract WBCs to the area. This process in known as
chemotaxis
4 signs of inflammation:
- redness -warmth - pain - swelling (edema)
Due to increase blood flow and vascular permeability in the affected region, which help phagocytic WBCs reach the general area and enter the affected tissue
inflammation
A major component in the 2nd line of defense, but also plays a role in adaptive immunity the ingestion and destruction of microorganisms or other small particles by phagocytes
phagocytosis
cells that perform phagocytosis are called
antigen-presenting cells
phagocytes that ingest foreign particles, isolate protein segments, and display them as antigens on their surfaces These peptides are then recognized by cells of the adaptive immune system as antigens and trigger an immune response by a specific (adaptive) immune cell
Antigen-presenting cells
part of phagocytosis: most numerous, “first responder”
neutrophils
take part in phagocytosis: “large eaters”; phagocytic monocytes that have grown to several times their original size after migrating out of the bloodstream
macrophages
take part in phagocytosis: cells with many extensions; found in many body tissues that are in contact with the external environment, such as the skin and mucous membranes
dendritic cells
lymphocytes (not T nor B) that kill tumor cells and cells infected by viruses - chemically triggers cell death and destruction - must have direct contact with target cell
Natural killer cells (NK cells)
NK cells recognize abnormal cells by using 2 different recognition receptors:
killer-activating receptor killer-inhibiting receptor
NK cells that bind to any of several common surface molecules found in cells
killer-activating cells
NK cells: - if the NK cell also binds to a protein found on the surface of normal cells, then the killing action is stopped
killer-inhibiting cells
only abnormal and foreign cells fail to bind to the _________ centers, so they are destroyed
killer-inhibiting centers
a protein synthesized by lymphocytes, macrophages, and fibroblasts that have been invaded by viruses
interferon