Chapter 22-end and Chapter 23 end Flashcards
Describe the activation of B cells
Usually occurs in secondary lymphatic structures after 1st exposure to antigen. Clones of activated plasma cells and B cells are formed.
Describe the effector response of activated B-cells
Binding of antigen-binding site of an antibody with antigen causes: neutralization; agglutination; and precipitation. The exposed Fc partion following antigen binding by antibody promotes: complement fixation; opsonization; and activation of NK cells.
Explain the role of Helper-Tcells in B-cell activation
During the 2nd stimulation of B-cells, Helper T-cells release IL-4 to stimulate the B-cell.
Describe the structure of antibodies
Y-shaped, soluble protrein composed of four polypeptide chains: two identical heavy chains & two identical light chains, w/flexibility at the hinge region.
Constant segment of antibody
Contains the Fc region, which is the portion of the antibody that determines the biological functions of the antibody.
Various segment of antibody
Located at the end of the “arms.” Contains the antigen binding site. Most have 2 sites, which allow antibody to bind to two antigenic determinants.
Describe the actions of antibodies.
They target specific antigens and “tag” them for elimination.
What is immunologic memory?
Memory is a significant feature of acquired immunity that protects us from subsequent exposures to a given antigen.
Primary response of immunologic memory.
Exposure to a specific antigen in the form of an active infection or a vaccine. It is the measurable response of antibody production, or titer. The lag phase (no detectable antibody in blood) may last 3-6 days. Production of antibody occurs within 1-2 weeks.
Secondary response of immunologic memory
Can occur after varying lengths of time following the 1st exposure.THere is a much shorter lag phase and antibody levels rise much faster than in the 1st response.
Natural active immunity
Individual is directly exposed to the antigen of an infectious agent.
Natural passive immunity
Occurs from the transfer of antibodies from the mother to the fetus across the placenta or to the baby in mother’s breastmilk.
Artificial active immunity
Exposure to a pathogen through a vaccine.
Artificial Passive Immunity
When serum containing antibodies against a specific antigen is transferred from one individual to another.
Describe the structure of alveoli
Alveoli are saccular outpocketings that are lined by a simple squamous epithelium.. They abut one another. Alveolar pores are small openings in the walls between some adjacent alveoli. BLood capillaries surround each alveolus. Alveolar wall is made up of two cell types, alveolar type I cells (a squamous alveolar cell) and alveolar type II cells (that secrete pulmonary surfactant. A third cell is the alveolar macrophage.
