Chapter 21 - Section 21.6 - Study Guide - Assess Your Learning Outcomes - Page 845: 1

Immune function is a complex and finely regulated process that plays a critical role in protecting the body from infections and diseases. However, there are several ways in which immune function can go awry, leading to various health issues. Here are three principal things that can go wrong with immune function: 1. **Immunodeficiency Disorders:** Immunodeficiency disorders occur when the immune system is compromised, either due to genetic factors or acquired conditions. In these disorders, the immune system is unable to effectively respond to infections and diseases. There are two main types of immunodeficiency disorders: - **Primary Immunodeficiency Disorders:** These are usually genetic and are present from birth. They result from defects in components of the immune system, such as B cells, T cells, phagocytes, or complement proteins. Examples include severe combined immunodeficiency (SCID) and common variable immunodeficiency (CVID). - **Secondary Immunodeficiency Disorders:** These are acquired and can be caused by factors such as infections (e.g., HIV/AIDS), certain medications (e.g., immunosuppressants used in organ transplants), chemotherapy, and chronic diseases (e.g., diabetes). Secondary immunodeficiencies weaken the immune response and make individuals more susceptible to infections. 2. **Autoimmune Diseases:** Autoimmune diseases occur when the immune system mistakenly targets and attacks the body's own healthy tissues. Instead of recognizing and attacking foreign invaders, the immune system produces antibodies and immune cells that attack its own cells and tissues. Examples of autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and type 1 diabetes. These conditions can lead to chronic inflammation and tissue damage, resulting in various symptoms and complications. 3. **Hypersensitivity Reactions:** Hypersensitivity reactions, also known as allergies, occur when the immune system overreacts to harmless substances in the environment (allergens). There are four types of hypersensitivity reactions: - **Type I Hypersensitivity:** Immediate allergic reactions, such as hay fever, asthma, and anaphylaxis, involve the release of histamines and other chemicals that cause rapid and severe symptoms. - **Type II Hypersensitivity:** Antibodies target specific cells or tissues, leading to conditions like autoimmune hemolytic anemia and certain drug reactions. - **Type III Hypersensitivity:** Immune complexes (antigen-antibody aggregates) accumulate and cause inflammation, as seen in diseases like systemic lupus erythematosus and rheumatoid arthritis. - **Type IV Hypersensitivity:** Delayed allergic reactions involve T cells and can lead to conditions like contact dermatitis (e.g., poison ivy reaction) and certain forms of drug reactions. These are just a few examples of the ways immune function can malfunction. The immune system is highly intricate, and disturbances in its regulation can result in a wide range of health problems. Proper diagnosis, treatment, and management of immune-related disorders are essential for maintaining overall health and well-being.

Immune function is a complex and finely regulated process that plays a critical role in protecting the body from infections and diseases. However, there are several ways in which immune function can go awry, leading to various health issues. Here are three principal things that can go wrong with immune function: 1. **Immunodeficiency Disorders:** Immunodeficiency disorders occur when the immune system is compromised, either due to genetic factors or acquired conditions. In these disorders, the immune system is unable to effectively respond to infections and diseases. There are two main types of immunodeficiency disorders: - **Primary Immunodeficiency Disorders:** These are usually genetic and are present from birth. They result from defects in components of the immune system, such as B cells, T cells, phagocytes, or complement proteins. Examples include severe combined immunodeficiency (SCID) and common variable immunodeficiency (CVID). - **Secondary Immunodeficiency Disorders:** These are acquired and can be caused by factors such as infections (e.g., HIV/AIDS), certain medications (e.g., immunosuppressants used in organ transplants), chemotherapy, and chronic diseases (e.g., diabetes). Secondary immunodeficiencies weaken the immune response and make individuals more susceptible to infections. 2. **Autoimmune Diseases:** Autoimmune diseases occur when the immune system mistakenly targets and attacks the body's own healthy tissues. Instead of recognizing and attacking foreign invaders, the immune system produces antibodies and immune cells that attack its own cells and tissues. Examples of autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and type 1 diabetes. These conditions can lead to chronic inflammation and tissue damage, resulting in various symptoms and complications. 3. **Hypersensitivity Reactions:** Hypersensitivity reactions, also known as allergies, occur when the immune system overreacts to harmless substances in the environment (allergens). There are four types of hypersensitivity reactions: - **Type I Hypersensitivity:** Immediate allergic reactions, such as hay fever, asthma, and anaphylaxis, involve the release of histamines and other chemicals that cause rapid and severe symptoms. - **Type II Hypersensitivity:** Antibodies target specific cells or tissues, leading to conditions like autoimmune hemolytic anemia and certain drug reactions. - **Type III Hypersensitivity:** Immune complexes (antigen-antibody aggregates) accumulate and cause inflammation, as seen in diseases like systemic lupus erythematosus and rheumatoid arthritis. - **Type IV Hypersensitivity:** Delayed allergic reactions involve T cells and can lead to conditions like contact dermatitis (e.g., poison ivy reaction) and certain forms of drug reactions. These are just a few examples of the ways immune function can malfunction. The immune system is highly intricate, and disturbances in its regulation can result in a wide range of health problems. Proper diagnosis, treatment, and management of immune-related disorders are essential for maintaining overall health and well-being.