Immune System Review Worksheet

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Questions and Answers

Explain the fundamental distinction between non-specific (innate) and specific (adaptive) immunity. Provide an example of each.

Non-specific immunity is the first line of defense, offering immediate, broad protection. Specific immunity is tailored to particular pathogens and develops over time. Example of non-specific: skin. Example of specific: antibodies.

Name five lymphoid organs and briefly describe their role in the immune system.

Bone marrow, thymus, spleen, lymph nodes, tonsils. Bone marrow produces immune cells; thymus matures T cells; spleen filters blood and monitors for pathogens; lymph nodes filter lymph; tonsils protect the entrance to the respiratory and digestive tracts.

Detail the unique roles of helper T cells and cytotoxic T cells in the adaptive immune response.

Helper T cells activate other immune cells through cytokine release. Cytotoxic T cells directly kill infected cells.

Describe how macrophages contribute to both the innate and adaptive immune responses.

In the innate response, macrophages phagocytose pathogens. In the adaptive response, they act as antigen-presenting cells to activate T cells. Signup and view all the answers

Elaborate on the process by which an antigen-presenting cell (APC) presents an antigen to a T cell.

APCs engulf and process antigens into peptide fragments. These fragments are then displayed on the APC surface bound to MHC molecules, which are recognized by T cell receptors. Signup and view all the answers

Discuss the role of antibodies in neutralizing pathogens and facilitating their clearance from the body.

Antibodies neutralize pathogens by binding to them, preventing infection of cells. They facilitate clearance by marking pathogens for phagocytosis or complement activation. Signup and view all the answers

Differentiate between the mechanisms of naturally acquired passive immunity and artificially acquired passive immunity, providing an example for each.

Naturally acquired passive immunity involves the transfer of antibodies from mother to fetus or infant (e.g., through placenta or breast milk). Artificially acquired passive immunity involves injection of antibodies from another source (e.g., antivenom). Signup and view all the answers

Explain the process of clonal selection and expansion in B cells during a humoral immune response.

Clonal selection is when an antigen binds to a B cell receptor, activating that specific B cell. Clonal expansion involves the proliferation of that B cell to produce more identical cells which differentiate into plasma cells and memory B cells. Signup and view all the answers

Describe the function of memory cells in the context of long-term immunity.

Memory cells provide a rapid and enhanced response upon subsequent encounters with the same antigen, leading to a quicker and more effective immune response. Signup and view all the answers

Outline the principal roles of the complement system in promoting immune defense.

The complement system enhances (complements) the ability of antibodies and phagocytic cells to clear microbes and damaged cells, promotes inflammation, and attacks the pathogen's plasma membrane. Signup and view all the answers

Explain the significance of the thymus in the development of mature T cells.

The thymus is where T cells mature and undergo selection, ensuring they can recognize foreign antigens but not self-antigens, preventing autoimmunity. Signup and view all the answers

What is the role of the lymph nodes in initiating adaptive immune responses?

Lymph nodes filter lymph, trapping antigens and providing a site where lymphocytes can encounter antigens, leading to activation of adaptive immune responses. Signup and view all the answers

How do antigens trigger an immune response once they are recognized by immune cells?

Antigens bind to specific receptors on immune cells (e.g., T cell receptors, B cell receptors), triggering intracellular signaling pathways that activate the immune cell and initiate an immune response. Signup and view all the answers

Explain the difference between the primary and secondary immune response.

The primary immune response occurs upon first exposure to an antigen, resulting in a slow and less intense response. The secondary immune response occurs upon subsequent exposure, leading to a faster and more robust response due to memory cells. Signup and view all the answers

Describe how B cells participate in the humoral immune response to eliminate extracellular pathogens.

B cells differentiate into plasma cells that produce antibodies specific to the pathogen, which then neutralize the pathogen or mark it for destruction by other immune cells. Signup and view all the answers

What are the central lymphoid organs and what is their primary function?

The central lymphoid organs are the bone marrow and thymus. The bone marrow is the site of hematopoiesis, where immune cells are produced. The thymus is where T cells mature. Signup and view all the answers

Explain the role of cytokines in the immune system.

Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis. They are produced by a variety of immune cells and act on other cells to modulate their function. Signup and view all the answers

Define humoral immunity and how it differs from cell-mediated immunity.

Humoral immunity involves antibody production by B cells to target extracellular pathogens. Cell-mediated immunity relies on T cells to directly kill infected cells or activate other immune cells to fight intracellular pathogens. Signup and view all the answers

Explain how passive immunity differs from active immunity, and provide an example of how each type of immunity can be acquired.

Passive immunity involves receiving pre-formed antibodies, providing immediate but temporary protection (e.g., maternal antibodies). Active immunity involves the body producing its own antibodies after exposure to an antigen (e.g., vaccination). Signup and view all the answers

Outline the steps involved in the activation of the complement system via the classical pathway.

The classical pathway is initiated when C1 binds to antibodies already bound to an antigen. This leads to a cascade of proteolytic activation of complement components, ultimately forming a membrane attack complex (MAC). Signup and view all the answers

Flashcards

Purpose of the Immune System?

The immune system's primary function is to defend the body against pathogens and maintain overall health.

Specific vs. Non-specific Immunity?

Non-specific immunity (innate) is a rapid, general response. Specific immunity (adaptive) is slower but targets specific threats. Examples: skin vs. antibodies.