Immune System Cells

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Questions and Answers

The immune system's ability to differentiate between 'self' and 'non-self' is crucial for preventing autoimmune reactions and effectively targeting pathogens. Which of the following best describes the primary consequence of a failure in this self/non-self discrimination?

The immune system attacking the body's own tissues and organs, leading to autoimmune disorders. (correct)
Reduced inflammatory responses, making it harder to clear infections.
Development of allergic reactions to common environmental substances.
Increased susceptibility to infectious diseases due to a weakened immune response.

Cytotoxic T cells (CD8+) and natural killer (NK) cells both play crucial roles in eliminating infected or cancerous cells. What is a key distinction in their mechanisms of target recognition and activation?

Cytotoxic T cells require prior sensitization to an antigen, whereas NK cells can recognize and kill target cells without prior exposure. (correct)
NK cells release antibodies to neutralize pathogens, whereas cytotoxic T cells directly lyse infected cells.
NK cells mediate cell-mediated immunity, while cytotoxic T cells are part of innate immunity.
Cytotoxic T cells primarily target viral infections, while NK cells are more effective against bacterial infections.

Antibodies produced by B lymphocytes are essential components of humoral immunity. What is the primary mechanism by which antibodies contribute to pathogen elimination?

Releasing histamine to promote inflammation and recruit immune cells to the site of infection.
Phagocytosing pathogens and presenting antigens to T cells.
Directly lysing infected host cells to prevent pathogen replication.
Neutralizing pathogens or marking them for destruction by other immune cells like phagocytes and complement. (correct)

The thymus gland is critical for the development of T lymphocytes. What specific process occurs in the thymus that ensures self-tolerance and the ability to distinguish between 'self' and 'non-self'?

Positive and negative selection of T cell precursors, eliminating self-reactive T cells. (D) Signup and view all the answers

Innate immunity and adaptive immunity are two arms of the immune system that work collaboratively to protect the body. Which of the following statements accurately contrasts innate and adaptive immunity?

Innate immunity is the first line of defense, providing rapid, non-specific responses, while adaptive immunity is slower to develop but provides specific and long-lasting protection. (A) Signup and view all the answers

Active and passive immunity are two ways to acquire adaptive immunity. Consider a scenario where a person receives a vaccination against influenza. Which type of immunity is being induced, and what is the underlying mechanism?

Active immunity, because the body is stimulated to produce its own antibodies and T cells in response to the vaccine antigens. (A) Signup and view all the answers

Antigen-presenting cells (APCs) like macrophages and dendritic cells play a critical role in initiating adaptive immune responses. What is their primary function in this process?

Phagocytosing pathogens and presenting processed antigens to T cells. (B) Signup and view all the answers

The complement system is a crucial part of the innate and adaptive immune response. What is the primary outcome of complement activation in pathogen elimination?

Opsonization of pathogens to enhance phagocytosis, direct lysis of pathogens, and promotion of inflammation. (C) Signup and view all the answers

Diagnostic tests for immune disorders often include assessment of immunoglobulin levels. Elevated levels of IgE are typically associated with which type of immune disorder?

Type I hypersensitivity reactions, such as allergies and anaphylaxis. (C) Signup and view all the answers

Hypersensitivity reactions are classified into four types (Type I-IV). Which type of hypersensitivity reaction is characterized by a delayed response mediated by T cells and cytokines?

Type IV (delayed-type hypersensitivity) (D) Signup and view all the answers

Anaphylaxis is a severe, life-threatening Type I hypersensitivity reaction. What is the immediate, first-line treatment for anaphylaxis, and how does it counteract the pathological processes?

Epinephrine, to reverse vasodilation, bronchoconstriction, and increase blood pressure. (A) Signup and view all the answers

Type II hypersensitivity reactions are cytotoxic, often involving antibody-mediated destruction of cells. Hemolytic transfusion reactions are an example of this. What is the underlying mechanism in hemolytic transfusion reactions?

Antibodies (IgG or IgM) binding to antigens on red blood cells, leading to complement activation and cell lysis. (B) Signup and view all the answers

Type III hypersensitivity reactions involve the deposition of antigen-antibody complexes in tissues, leading to inflammation and tissue damage. Which of the following conditions is a classic example of a Type III hypersensitivity reaction?

Serum sickness (A) Signup and view all the answers

Contact dermatitis, such as poison ivy allergy, is a classic example of a Type IV hypersensitivity reaction. What is the primary effector cell type responsible for the tissue damage in this reaction?

Cytotoxic T lymphocytes and helper T lymphocytes releasing cytokines. (A) Signup and view all the answers

Autoimmune disorders arise when the immune system mistakenly targets the body's own tissues. Rheumatoid arthritis (RA) is an autoimmune disorder primarily affecting the joints. What is the main immunological process driving joint damage in RA?

Chronic inflammation driven by autoantibodies and T cells targeting the synovial membrane. (C) Signup and view all the answers

Systemic lupus erythematosus (SLE) is a chronic, multisystem autoimmune disease. What is a hallmark characteristic of SLE in terms of autoantibody production?

Production of a wide range of autoantibodies targeting various self-antigens, including nuclear antigens (ANAs). (C) Signup and view all the answers

Multiple sclerosis (MS) is an autoimmune disorder that affects the central nervous system. What is the primary target of the autoimmune attack in MS?

Myelin sheath of nerve fibers in the brain and spinal cord. (C) Signup and view all the answers

Type 1 diabetes mellitus is an autoimmune disease resulting in insulin deficiency. What specific cells are targeted and destroyed by the immune system in type 1 diabetes?

Beta cells in the pancreas (producing insulin). (B) Signup and view all the answers

Immunodeficiency disorders can be primary (genetic) or secondary (acquired). HIV/AIDS is a well-known example of a secondary immunodeficiency. What is the primary mechanism by which HIV causes immunodeficiency?

Infection and destruction of CD4+ T helper cells, leading to broad immunosuppression. (C) Signup and view all the answers

Severe Combined Immunodeficiency (SCID) is a primary immunodeficiency characterized by a profound defect in both T and B cell function. What is the most effective treatment for SCID to restore immune function?

Hematopoietic stem cell transplantation to reconstitute the immune system. (A) Signup and view all the answers

In HIV infection, the progression to AIDS is marked by a critical decline in CD4+ T cell count. What CD4+ T cell count is generally indicative of AIDS and increased risk of opportunistic infections?

Below 200 cells/µL (B) Signup and view all the answers

Antiretroviral therapy (ART) is the standard treatment for HIV infection. What is the primary goal of ART in managing HIV and preventing progression to AIDS?

To suppress viral replication, reduce viral load, and preserve immune function. (C) Signup and view all the answers

Which of the following best describes the role of helper T cells (CD4+) in the immune response?

Assisting in the activation of B cells and cytotoxic T cells. (D) Signup and view all the answers

Suppressor T cells, also known as regulatory T cells, play a critical role in maintaining immune homeostasis. What is their primary function?

Suppressing immune responses to prevent autoimmunity and excessive inflammation. (A) Signup and view all the answers

Monocytes differentiate into macrophages and dendritic cells. What is a key shared function of macrophages and dendritic cells in the immune response?

Phagocytosis of pathogens and antigen presentation to T cells. (C) Signup and view all the answers

Granulocytes, including neutrophils, eosinophils, and basophils, are involved in innate immunity and inflammatory responses. What is a primary function commonly associated with eosinophils?

Defense against parasitic infections and involvement in allergic reactions. (D) Signup and view all the answers

Mast cells are granulocytes that are strategically located in tissues throughout the body. What is the primary role of mast cells in immediate hypersensitivity (Type I) reactions?

Releasing histamine and other mediators upon IgE crosslinking, leading to vasodilation and bronchoconstriction. (D) Signup and view all the answers

Lymph nodes are secondary lymphoid organs that play a crucial role in adaptive immune responses. What is the primary function of lymph nodes in immunity?

Filtering lymph and facilitating interactions between immune cells and antigens. (D) Signup and view all the answers

Mucosa-associated lymphoid tissue (MALT) is strategically located throughout mucosal linings. What is the primary function of MALT in the immune system?

Initiating immune responses to antigens entering through mucosal surfaces. (A) Signup and view all the answers

Physical barriers, such as the skin and mucous membranes, are a critical component of innate immunity. How do mucous membranes contribute to preventing pathogen entry?

Trapping pathogens in mucus and using cilia to expel them. (C) Signup and view all the answers

Chemical defenses are also part of innate immunity. What is the role of enzymes like lysozyme found in tears and saliva in preventing infection?

Disrupting the cell walls of bacteria, leading to their lysis. (A) Signup and view all the answers

Memory cells are a hallmark of adaptive immunity, providing long-lasting protection. What is the primary function of memory B cells and memory T cells upon re-exposure to a previously encountered antigen?

To mount a faster, stronger, and more effective secondary immune response. (C) Signup and view all the answers

A complete blood count (CBC) with differential is a common diagnostic test for immune disorders. What type of information about the immune system can be gained from a CBC with differential?

Quantities and proportions of different types of white blood cells (leukocytes). (B) Signup and view all the answers

Immunoglobulin levels (IgG, IgM, IgA, IgE) are often measured in diagnostic tests for immune disorders. What clinical information can be derived from measuring serum immunoglobulin levels?

Quantification of antibody levels, which can indicate humoral immune status or specific immune responses. (C) Signup and view all the answers

Flashcards

Immunity

The body's defense mechanism against disease, distinguishing self from non-self to protect against pathogens, toxins, and mutations.

Immune System Cells

Key cells (T cells, B cells, NK cells, monocytes, granulocytes) mediating immunity. T and B cells responsible for adaptive immunity.

T Lymphocytes (T cells)

Mature in the thymus and responsible for cell-mediated immunity. Includes helper, suppressor, and cytotoxic types.