defensive substance的意思

英文：

The Usage of Defensive Substance

Defensive substance, a term used in biochemistry and immunology, is an anti-bacterial and anti-fungal chemical found in the body. It helps to protect the body from infections and diseases as it works against pathogenic organisms.

Defensive substances can act directly against invading organisms or work indirectly. Direct action is more physical in nature and involves direct contact between the substances and the pathogens. This can include chemical reactions like acid reactions and protein unfolding. Indirect action involves stimulating the immune system to respond to the pathogen.

In general, defensive substances can be divided into four categories. These include the humoral, or chemical, defenses; the cell-mediated, or physical, defenses; the natural killer cells, or active immunity; and the immune response, or acquired immunity.

Humoral defenses refer to substances such as antibodies and enzymes. These are produced by the body and released into the bloodstream in response to an infection or to fight an invading organism. They have the ability to recognize and attack specific pathogenic organisms.

Cell-mediated defenses involve cell components such as lymphocytes and macrophages. These cells can recognize and attack specific pathogens and then kill them. Natural killer (NK) cells are part of the immune system, and they are responsible for actively killing invading organisms. They are able to recognize and attack specific pathogens without the assistance of antibodies.

The immune response, or acquired immunity, is caused by previous exposures to a particular pathogen. The body “remembers” the pathogen and can then mount a quicker and more effective response when exposed to it again.

Defensive substances can also be labeled as preformed, inducible, or innate. Preformed defenses are substances that are already present in the body and are ready to act against an infection. Inducible defenses are substances that are created in response to an infection, and innate defenses are substances that are always present in the body.

Defensive substances are an important part of the body’s defense system. They can help protect the body from disease and infection, and they can help the body fight off viruses and bacteria. Understanding the different types of defensive substances is essential in understanding how the immune system works and how it can be strengthened.