Exam 24: A: Immune System

The most numerous type of phagocyte is the macrophage.

T cells,by definition,are lymphocytes that have passed through the thyroid gland.

The combining site on an antibody determines the specificity of that antibody for an antigen.

The membrane attack complex is used by macrophages to mark bacteria for phagocytosis and antibody attack.

A chemotactic factor attracts antibodies to the site of infection.

Neutrophils function in the immune system by producing immunoglobulins.

Pavementing is the attraction of neutrophils to the site of an infection.

When antibodies cause antigens to agglutinate,it allows them to be disposed of by phagocytes more easily.

In phagocytosis,a foot-like projection,called a phagosome,extends toward a microorganism.

The immune mechanism that provides a defense by acting against cancer is termed nonspecific immunity.

Complement can be activated only by the specific immune system.

The somatic recombination hypothesis is one possible explanation for the diversity of antibodies.

Humoral immunity occurs within the plasma.

B cells are named after a structure in birds.

A macrophage can migrate out of the bloodstream.

Suppressor T cells help B cells differentiate into antibody-secreting plasma cells by secreting cytokines such as interleukin-2 and interleukin-4.

The second stage of B cell development usually takes place in the lymph nodes and spleen.

Cytokines include leukotrienes,interferons,and histamine.

All antigens have epitopes of the same shape.

Species resistance refers to a phenomenon in which the genetic characteristics common to a species provide defense against certain pathogens.