Immune System Overview

Immune System Overview

• The immune system is a complex network of cells, tissues, and organs that work together to defend the body against infection and disease.
• It is composed of two main branches: the innate immune system and the adaptive immune system.

Innate Immune System

• Provides immediate, non-specific defense against infection.
• Includes physical barriers (skin, mucous membranes), cellular components (neutrophils, macrophages), and chemical factors (complement system).

Adaptive Immune System

• Provides specific, long-term immunity against specific pathogens.
• Involves the activation of T cells and B cells.
• Involves antigen processing and presentation, and the production of antibodies.

Cells of the Immune System

• T cells (T lymphocytes):
  • Recognize and eliminate infected cells or produce chemical signals to activate other immune responses.
  • Divided into two subtypes: CD4+ (T helper cells) and CD8+ (cytotoxic T cells).
• B cells (B lymphocytes):
  • Produce antibodies (immunoglobulins) to neutralize or remove pathogens.
  • Can also activate other immune responses.
• Dendritic cells: Antigen-presenting cells that activate T cells and B cells.
• Macrophages: Engulf and digest foreign particles and microorganisms.
• Neutrophils: Phagocytic cells that engulf and digest foreign particles and microorganisms.

Immune Responses

• Humoral immunity: Involves the production of antibodies by B cells to neutralize or remove pathogens.
• Cell-mediated immunity: Involves the activation of T cells to eliminate infected cells or produce chemical signals.

Immunological Tolerance

• The ability of the immune system to distinguish between self and non-self.
• Involves the regulation of immune responses to prevent autoimmune diseases.

Immunological Disorders

• Autoimmune diseases: The immune system attacks self-antigens, leading to diseases such as rheumatoid arthritis and lupus.
• Immunodeficiency diseases: The immune system is weakened, making the body more susceptible to infections, such as HIV/AIDS.
• Hypersensitivity reactions: Overactive immune responses, such as allergies and anaphylaxis.

Immune System Overview

• The immune system is a complex network that defends the body against infection and disease, comprising two main branches: innate and adaptive.

Innate Immune System

• Provides immediate, non-specific defense against infection, including:
  • Physical barriers (skin, mucous membranes)
  • Cellular components (neutrophils, macrophages)
  • Chemical factors (complement system)

Adaptive Immune System

• Provides specific, long-term immunity against specific pathogens, involving:
  • Activation of T cells and B cells
  • Antigen processing and presentation
  • Production of antibodies

Cells of the Immune System

• T cells (T lymphocytes):
  • Recognize and eliminate infected cells or produce chemical signals
  • Divided into two subtypes: CD4+ (T helper cells) and CD8+ (cytotoxic T cells)
• B cells (B lymphocytes):
  • Produce antibodies (immunoglobulins) to neutralize or remove pathogens
  • Can also activate other immune responses
• Dendritic cells:
  • Antigen-presenting cells that activate T cells and B cells
• Macrophages:
  • Engulf and digest foreign particles and microorganisms
• Neutrophils:
  • Phagocytic cells that engulf and digest foreign particles and microorganisms

Immune Responses

• Humoral immunity:
  • Involves production of antibodies by B cells to neutralize or remove pathogens
• Cell-mediated immunity:
  • Involves activation of T cells to eliminate infected cells or produce chemical signals

Immunological Tolerance

• The immune system's ability to distinguish between self and non-self, involving regulation of immune responses to prevent autoimmune diseases.

Immunological Disorders

• Autoimmune diseases:
  • The immune system attacks self-antigens, leading to diseases such as rheumatoid arthritis and lupus
• Immunodeficiency diseases:
  • The immune system is weakened, making the body more susceptible to infections, such as HIV/AIDS
• Hypersensitivity reactions:
  • Overactive immune responses, such as allergies and anaphylaxis