BChD I Immune System Problems Lecture 15

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Questions and Answers

What role do IgE antibodies play in allergic responses?

IgE antibodies bind to mast cells and basophils, leading to the release of histamine and initiating an inflammatory response.

Identify two common symptoms of allergies.

Runny nose and conjunctivitis.

How do autoimmune diseases differ from normal immune responses?

Autoimmune diseases occur when the immune system mistakenly targets self-antigens instead of ignoring them.

What triggers an autoimmune reaction, as described in the content?

Triggers may include a reduction in suppressor T cell activity and increased stimulation of helper T cells. Signup and view all the answers

Describe one effect of multiple sclerosis on the nervous system.

Multiple sclerosis leads to the destruction of the myelin sheath, causing muscle weakness and spasms. Signup and view all the answers

What is the clinical significance of the Major histocompatibility complex (MHC) during organ transplants?

MHC molecules activate an immune response when they present nonself antigens, leading to graft rejection. Signup and view all the answers

Provide an example of an autoimmune disease and its symptom.

Lupus; symptoms include extreme fatigue and a butterfly-shaped rash on the face. Signup and view all the answers

What happens to the immune system in allergic contact reactions?

The immune system reacts excessively to foreign substances, like metals in braces, causing localized inflammation. Signup and view all the answers

What are the three ways that immunodeficiency can occur due to disruptions in lymphocyte functioning?

Improper embryological development of lymphoid organs, infections that depress immune function, and exposure to immunosuppressive agents. Signup and view all the answers

What is Severe Combined Immune Deficiency (SCID) and how is it treated?

SCID is a congenital immune disorder characterized by low or no B and T cells production, which is fatal if untreated; it can be treated with bone marrow transplants. Signup and view all the answers

What is the causative agent of Acquired Immune Deficiency Syndrome (AIDS)?

AIDS is caused by the human immunodeficiency virus (HIV). Signup and view all the answers

How does HIV impair the immune system's function, particularly regarding CD4 T cells?

HIV targets and impairs CD4 T cells, which depresses both cell-mediated and antibody-mediated immune responses. Signup and view all the answers

Define hypersensitivity in the context of the immune system.

Hypersensitivity is an inappropriate or excessive response of the immune system to either harmless antigens or self-antigens. Signup and view all the answers

What role do allergens play in the immune response associated with allergies?

Allergens are harmless environmental antigens that trigger excessive immune responses upon repeated exposure. Signup and view all the answers

What is the relationship between IgE production and allergic responses?

IgE is produced by the immune system in response to allergens and is responsible for mediating allergic reactions. Signup and view all the answers

What types of conditions fall under the acquired category of immunodeficiency?

Acquired immunodeficiency can develop from nutritional deficiencies, trauma, stress, or viral infections. Signup and view all the answers

Study Notes

Immune System Overview

Immune response complexity leads to various clinical conditions.
Immunodeficiency occurs when the immune system fails to combat pathogens.
Disruptions in lymphocyte functioning can cause immunodeficiency.
Causes include:
- Improper embryological development of lymphoid organs.
- Infections that depress immune function.
- Exposure to immunosuppressive agents (e.g., radiation, drugs).
Immunodeficiency is classified into:
- Congenital: Present from birth.
- Acquired: Develops post-birth.

Immunodeficiency Diseases

Congenital conditions are rare genetic defects affecting lymphocyte development.
- Example: Severe Combined Immune Deficiency (SCID), marked by low or absent B and T cells, leading to severe immunity issues.
- SCID is fatal if untreated and can be treated with bone marrow transplants.
Acquired conditions arise from factors such as nutritional deficiencies, trauma, stress, or infections.
- Example: Acquired Immune Deficiency Syndrome (AIDS) caused by the Human Immunodeficiency Virus (HIV).
- HIV targets CD4 T cells, impairing immune responses, making patients susceptible to infections.

Hypersensitivity

Hypersensitivity refers to inappropriate or excessive immune responses, classified into:
- Allergies: Excessive responses to harmless environmental antigens (allergens).
  - Symptoms include runny nose, conjunctivitis, and urticaria (rash).
  - The body produces IgE antibodies upon repeated allergen exposure.
  - Allergens can include medications (e.g., penicillin), preservatives, and cosmetics.
- Autoimmunity: The immune system incorrectly targets self-antigens, leading to diseases.
  - Triggered by malfunctioning recognition systems and decreased suppressor T cell activity.
  - Example: Lupus, affecting multiple body systems, marked by fatigue and a butterfly-shaped facial rash.
  - Example: Multiple Sclerosis, where antibodies attack the myelin sheath, causing muscle weakness and balance issues.

Tissue Transplants

Major Histocompatibility Complex (MHC) molecules are crucial for organ transplants.
MHC molecules present non-self antigens to lymphocytes, initiating immune responses.
Post-transplant, T cells recognize donor MHC molecules, leading to potential graft rejection.

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Description

Explore the complexities of the immune response and its clinical significance in this lecture. Learn about various immunodeficiencies and how they affect lymphocyte functioning, leading to increased vulnerability to pathogens. This quiz will deepen your understanding of immune system disorders.