Immune System Basics

The immune system is a complex network of cells, tissues, and organs that work together to defend the body against harmful substances, such as bacteria, viruses, and toxins.

Red blood cells are responsible for carrying oxygen and nutrients to cells throughout the body. They are not part of the immune system.

Neutrophils are the most abundant type of white blood cell and are the first to respond to infection. They engulf and destroy foreign particles, such as bacteria and viruses.

Antibodies are proteins produced by the immune system in response to the presence of foreign particles. They bind to foreign particles and mark them for destruction by other immune cells.

Adaptive immunity is a type of immune response that is specific to a particular pathogen. It is responsible for long-term protection against infection.

The thymus gland is a small organ located in the chest. It is responsible for producing T cells, a type of white blood cell that plays a key role in the adaptive immune response.

Platelets are involved in blood clotting and are not part of the immune system.

The spleen is a large organ located in the abdomen. It filters blood and removes foreign particles, such as bacteria and viruses.

Humoral immunity is a type of immune response that involves the production of antibodies. Antibodies are proteins that bind to foreign particles and mark them for destruction by other immune cells.

Lymph nodes are small, bean-shaped structures located throughout the body. They filter lymph, a fluid that contains white blood cells, and remove foreign particles, such as bacteria and viruses.

IgD is not a type of antibody. It is a type of immunoglobulin that is found on the surface of B cells.

The bone marrow is a soft tissue located inside bones. It is responsible for producing white blood cells, including neutrophils, lymphocytes, and monocytes.

Cell-mediated immunity is a type of immune response that involves the destruction of infected cells by cytotoxic T cells.

The complement system is a group of proteins that work together to activate the immune response. It helps to opsonize foreign particles, making them easier for phagocytes to engulf and destroy.

Lymphocytes are not phagocytes. They are a type of white blood cell that is responsible for the adaptive immune response.