1 Immune System Disorders and Immune Dysfunction Free Online FlashCards

What characterizes innate immunity?

Innate immunity is the rapid, broad first response. It includes barriers, phagocytes, natural killer cells, inflammation, and complement.

What characterizes adaptive immunity?

Adaptive immunity develops after exposure and targets particular antigens. B cells and T cells are central to this response.

What do plasma cells produce, and what do these molecules bind?

B cells can become plasma cells that secrete antibodies, which bind particular antigens and can neutralize them or help remove them.

What are two major roles of T cells?

T cells coordinate immune activity or kill infected cells. Antigen-presenting cells, including dendritic cells, help initiate many T-cell responses.

What is the role of adaptive immune memory?

Some B and T cells persist as memory cells after infection or vaccination, enabling a faster response to a later encounter with the same antigen.

What does hypersensitivity mean?

Hypersensitivity is an inappropriate or exaggerated immune response that can damage tissues instead of protecting them.

What mechanism defines Type I hypersensitivity?

Type I is an immediate reaction involving IgE and activated mast cells releasing inflammatory mediators; examples include hives and anaphylaxis.

How does Type II hypersensitivity cause tissue injury?

In Type II hypersensitivity, antibodies bind antigens on cells or tissues and may activate complement or other destructive mechanisms.

What causes tissue inflammation in Type III hypersensitivity?

Type III hypersensitivity occurs when antigen–antibody complexes deposit in tissues and provoke inflammation; serum sickness is an example.

What mediates Type IV hypersensitivity, and when does it occur?

Type IV is delayed and T-cell-mediated, often causing tissue injury over hours to days. Poison ivy contact dermatitis is an example.

Do hypersensitivity types indicate reaction severity?

The four categories describe different mechanisms, not levels of severity. Type I ranges from localized symptoms to life-threatening anaphylaxis, and other types can also cause significant injury.

What is an immunodeficiency?

An immunodeficiency is a defect in immune-system development or function that increases vulnerability to infection and may have other complications.