Exam 19 - The Immune System

I. The Immune System

• Adaptive Immunity: A specific reaction to each invading antigen, able to remember previous attacks.
• Allergen: A substance causing a hypersensitive reaction, not necessarily harmful.
• Anaphylactic Shock: A severe, potentially fatal allergic reaction.
• Antigen: A substance recognized as foreign, triggering an immune response.
• Attenuated: Weakening the virulence (harmfulness) of a disease organism.
• Autoimmune: Immune response targeting the body's own tissues.
• Autologous: Originating within the individual.
• Cellular Immunity: Acquired immunity dominated by small T cells.
• Humoral Immunity: Acquired immunity responding to antigens like bacteria and foreign tissue, mediated by B cells.
• Hypersensitivity: Excessive reaction to a stimulus.
• Immunity: The quality of being resistant to a particular disease.
• Immunization: Process inducing resistance to infection.
• Immunocompetence: The ability of the immune system to respond to antigens.
• Immunodeficiency: A condition with inadequate immune system response.
• Immunogen: A substance provoking an immune response.
• Immunology: The study of the immune system.
• Immunosuppressive: Agents suppressing the immune system's response.
• Immunotherapy: Treatment using increasing doses of offending allergens.
• Innate Immunity: The body's initial defense, with physical and chemical barriers.
• Lymphokine: Chemical factors released by T cells, attracting macrophages.
• Plasmapheresis: Removal of plasma components causing disease.

II. Functions of the Immune System

• Protecting the body's internal environment from invaders (destroying antigens and pathogens).
• Maintaining homeostasis by removing damaged cells.
• Serving as a surveillance network, recognizing and guarding against abnormal cells.

III. Types of Immunity

• Natural (Innate) Immunity:
  • Body's first line of defense, using physical and chemical barriers.
  • Protecting internal/external environments using skin, mucous membranes, and secretions.
• Acquired (Adaptive) Immunity:
  • Body's second line of defense, activated when the first line fails.
  • Using specialized cells and tissues (thymus, spleen) for specific immunity.
  • Creating antibodies to specific antigens, both naturally and artificially.
  • Maintaining an "immune memory" to quickly respond on subsequent exposures.

IV. Aging and the Immune System

• Aging negatively impacts the immune system, decreasing thymus size and activity,
• Decreasing activation ability of T and B cells, shortening their lifespan.
• Memory cells accumulate, while bone marrow remains relatively unaffected.

V. Immunocompetence, Immunodeficiency, and Autoimmunity

• Immunocompetent: Normal functioning immune system.
• Immunodeficiency: Inadequate immune function.
• T-Cell, B-cell, and combined T and B-cell deficiencies are described.
• Autoimmunity: Immune response to one's own tissues.

VI. Hypersensitivity Disorders

• Excessive immune response to a harmless substance (allergen).
• Allergic symptoms varying from mild to severe, due to IgE, humoral, or cellular reactions.
• Exposure to allergens (e.g., pollen) triggers an immune response.

VII. Anaphylaxis

• Acute/potentially fatal allergic reaction, rapid onset, severe and possibly fatal reactions.
• Respiratory and cardiovascular symptoms: predominant and early recognition is critical.
• Assessment: Early recognition and immediate treatment are essential.

VIII. Latex Allergy

• Latex exposure can induce sensitization, resulting in an allergic reaction.
• Exposure through common items (gloves, medical equipment).
• Allergic reaction can range from skin irritation to full-blown anaphylaxis.
• Similar proteins in latex and certain foods can cause allergic cross-reactions.

IX. Transfusion Reactions

• Mismatched blood transfusions can lead to various reactions, ranging from mild to severe.
• Transfusion timing is critical to prevent bacterial growth.
• Symptoms can range from mild skin irritation to severe, life-threatening complications.

X. Organ Transplant

• Transfer of healthy organs/tissues between individuals.
• Immune system's rejection response needs to be addressed before/during transplant.

XI. Autografting

• Transferring tissue from one body part to another within the same individual; rarely rejected.

XII. Allografting

• Transfer tissue between members of the same biological species.
• More likely to be rejected than autografts because of different genetic material.

XIII. Isografting

• Transferring tissue between genetically identical individuals (e.g., twins).
• Less likely to be rejected because of identical genetic material.

XIV. Tissue Rejection

• Rejection is a delayed response; takes days to develop after transfusion/transplant.
• Immune cells can recognize the foreign tissue and attack it.
• Chemical agents are sometimes used to combat this response.

XV. Immunodeficiency Disorders

• Characterized by increased susceptibility to infections.
• Can manifest as recurrent, chronic, and severe infections.
• Can involve primary or secondary immune deficiencies.

XVI. Autoimmune Disorders

• Immune system mistakenly attacks the body's own tissues.
• Can cause diverse body-system inflammation.
• Can stem from various factors like environmental exposure, genetics, and viral infections.

XVII. Plasmapheresis

• Removal of diseased components from the plasma.
• Replacing bad plasma components with a saline/albumin solution.