BIO1306 Ch 43 Quiz

Antigens. Antigens are foreign molecules that initiate an immune response.

The leukocytes of the innate immune system are mast cells, macrophages, and neutrophils.

Pattern-recognition receptors on leukocytes recognize and bind to unique molecules on the pathogens, such as the amino acid N-formylmethionine in bacteria. This receptor binding leads to activation of the innate immune response.

Macrophages are leukocytes that can engulf and digest a pathogen.

Mast cells release chemicals that dilate nearby capillaries, increasing their permeability and allowing blood components to enter the region from the bloodstream, thus causing localized swelling.

The first response to broken skin is the release of clotting proteins from platelets in the bloodstream, which decreases bleeding and helps to seal the wound.

True. The site of inflammation may also become red due to increased blood flow at the site; the inflammatory response continues until all invaders are eliminated and the wound is repaired.

Innate immunity and acquired immunity are both characteristics of all vertebrate animals. Only vertebrate animals have fully developed acquired immunity to supplement their innate immunity.

An antigen is a foreign molecule that evokes a specific response by a lymphocyte. Antigen molecules can be a part of any type of organism. Antigen molecules could also be a part of a product of an organism such as pollen or feces.

The fact that there are about a million different antigen receptors possible in human B cells is based on recombination of the segments of the receptor DNA that make up the functional receptor genes of differentiated B cells.

3) macrophage. Macrophages are phagocytic leukocytes.

Helper T cells. Specific helper T cells recognize specific antigen-class II MHC complexes. The result of this is an activated helper T cell that stimulates both humoral and cell-mediated immune responses.

Plasma cells develop from B cells that have been stimulated by the interleukin-2 secreted by helper T cells.

The role of cytotoxic T cells is the secretion of perforin, which plays a role in the cell-mediated immune response. Perforin causes the lysis of pathogen-infected body cells; it is a component of the cell-mediated immune response.

Clonal selection is the division of B cells that have been stimulated by binding to an antigen, which results in the production of cloned plasma cells and memory cells.

4) Memory Cells. Memory cells are responsible for the rapidity of the secondary immune response and for long-term immunity.

3) Plasma cells. Plasma cells are clones of antibody-secreting B cells.

Extracellular pathogens such as viruses and bacteria in body fluids are attacked by antibodies from plasma cells. Antibodies are part of the "humoral" immune responses. Circulating antibodies encounter microorganisms in body fluids and complex with them to "mark" them for further counterattack.

Tissues are immunogically "typed" before an organ transplant to make sure that the donor and recipient match as closely as possible in their MHC (major histocompatibility complex) proteins.

Macrophages are large, phagocytic cells that can leave the circulation and enter the tissues of the body. Once resident in the tissues, macrophages are active phagocytes that capture and digest many microorganisms.

The role of active cytotoxic T cells is to attack body cells that have been infected. Nonspecific defense includes natural killer cells that destroy virus-infected body cells, and abnormal cells that could form tumors. Cytotoxic (killer) T lymphocytes kill cancer cells and cells infected by viruses or other intracellular pathogens.

Cell-mediated immunity differs from humoral immunity in that they respond differently to invaders. Humoral immunity is a function of B cells and antibody production, whereas cell-mediated immunity is a function of the activation of cytotoxic T cells.

Helper T cells are part of cell-mediated immune responses. Cell-mediated immunity depends on the activation of T lymphocytes.

A child frequently given antibiotics is more likely to develop allergies and asthma.

Lactobacillus johnsonii. Lactobacillus johnsonii is a probiotic that produces enzymes that digest milk which are found in the gut and the vagina. During natural birth the baby would normally be coated in them.

Clostridium difficile typically infects the digestive system.

Fecal transplant. The purpose of fecal transplant is to replace good bacteria that has been killed or suppressed, usually by the use of antibiotics, causing bad bacteria, specifically Clostridium difficile, or C. diff., to over-populate the colon. This infection causes a condition called C. diff. colitis, resulting in often debilitating, sometimes fatal diarrhea.