Immune System

Immunity is resistance to disease resulting from the presence of foreign substances or _______ in the body

Antigens

What signifies that a lymphocyte has become immunocompetent?

Appearance of antigen-specific receptors on membrane of lymphocytes

The major actors in the immune response are two lymphocyte populations, the _____ and the _____.

B Cells & T Cells

Produces antibodies that are released to body fluids

B cell

Progeny are plasma cells

B cell

What triggers the process of clonal selection in a T or B cell?

Binding to "its" antigen

Because pathogens are likely to use both ____ and ______ as a means of getting around the body, ______and other lymphatic tissues are in an excellent position to detect their presence

Blood, Lymph, Lymph Nodes

When living cells provide the protection, the immunity is called _______

Cellular immunity

During what period of life does immunocompetence develop?

Fetal life

When this resistance is provided by antibodies released to body fluids, the immunity is called _____

Humoral immunity

What determines which antigen a particular T or B cell will be able recognize?

Its genes

Phagocytic cells that act as accessory cells in the immune response are the _____

Macrophages

Accounts for most of the lymphocytes in the circulation

T cell

Is responsible for directly attacking foreign cells or virus-infected cell

T cell

Originates in bone marrow from stem cells called hemocytoblasts

T cell

Progeny include suppressors, helpers, and killers

T cell

Bears a cell-surface receptor capable of recognizing a specific antigen

T cell & B cell

Forms clones upon stimulation

T cell & B cell

Progeny include memory cells

T cell & B cell

Small molecules are not usually antigenic, but when they bind to self cell surface proteins they may act as ______, and then the complex is recognized as foreign, or ______

haptens, nonself

Antigens are substances capable of mobilizing the

immune system

Transferring antibodies from one person to another

passive immunity

Of all the foreign molecules that act as complete antigens _______ are the most potent

proteins

Vaccination with antigen (lasts for years)

active immunity