Defense

Defense is a term used in various fields, including medicine, psychology, and biology, to refer to mechanisms or strategies used to protect against harm or damage. In the context of medicine, defense mechanisms are often related to the body's immune system and its ability to fight off disease and infection.

Medical Defense Mechanisms

The human body has a complex system of defense mechanisms that work together to protect against disease and infection. These mechanisms can be broadly categorized into two types: innate (non-specific) and adaptive (specific).

Innate Defense Mechanisms

Innate defense mechanisms are the body's first line of defense against pathogens. They are non-specific, meaning they respond to all pathogens in the same way. These mechanisms include physical barriers like the skin and mucous membranes, as well as cells and chemicals that attack pathogens.

Physical Barriers

The skin and mucous membranes act as physical barriers, preventing pathogens from entering the body. The skin is the largest organ of the body and provides a tough, physical barrier against pathogens. Mucous membranes, which line the body's internal surfaces, trap pathogens and move them out of the body.

Cells and Chemicals

The body also uses cells and chemicals to attack pathogens. White blood cells, or leukocytes, are a key part of this defense. They can engulf and destroy pathogens in a process called phagocytosis. The body also produces chemicals, like interferons and complement proteins, that inhibit the growth of pathogens and help white blood cells destroy them.

Adaptive Defense Mechanisms

Adaptive defense mechanisms are the body's second line of defense. They are specific, meaning they target specific pathogens. These mechanisms include antibodies and T cells, which recognize and destroy specific pathogens.

Antibodies

Antibodies are proteins produced by B cells, a type of white blood cell. They recognize and bind to specific antigens (substances that the body recognizes as foreign), marking them for destruction by other cells of the immune system.

T Cells

T cells are another type of white blood cell. They recognize and kill infected cells directly, and also help coordinate the immune response by signaling other cells to attack.

See Also

• Immune system
• Inflammation
• Infection

References

Defense Resources
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