Cataphylaxis is a term used to describe the complete blockage of a blood vessel by a blood clot. The word is derived from the Greek words "kata" meaning down or against, "phylaxis" meaning protection, and "axis" meaning a central line or straight line. The IPA transcription for cataphylaxis is /kætəfɪˈlæksɪs/. The emphasis on "pha" in the pronunciation helps to differentiate it from similar-sounding words like "cataclysm" or "cataphract", which are not related to blood clots.
Cataphylaxis is a term used in biology and physiology to describe a phenomenon wherein the response to a stimulus weakens or diminishes over time. It refers to the gradual decline or attenuation of a physiological or behavioral response to a repeated or prolonged exposure to a particular stimulus. The term is commonly used in the context of immune responses or anaphylactic reactions.
In immunology, cataphylaxis describes a process whereby the immune system becomes less responsive to a specific antigen due to repeated exposure. This reduced responsiveness can lead to a decreased ability to mount an effective immune response against the antigen, potentially resulting in reduced efficacy of vaccines or increased susceptibility to certain pathogens.
In the realm of allergic reactions, cataphylaxis refers to a diminishing sensitivity or tolerance to an allergen. Individuals with allergies may experience a decrease in the severity of symptoms or a decrease in the body's reaction to the allergen over time.
Cataphylaxis can also be observed in non-biological contexts, such as in the field of pharmacology. It may refer to the diminishing effectiveness or tolerance to a particular medication over time, necessitating higher doses for the same therapeutic effect.
Overall, cataphylaxis encompasses the gradual decline in responsiveness observed in various biological and physiological systems and is characterized by a weakened or diminished response to a stimulus following repeated exposure or prolonged exposure to a particular agent, antigen, or substance.
Transport of leucocytes and antibodies to the site of infection.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.
The term "cataphylaxis" is derived from the combination of two Greek words: "kata" (κατά) meaning "down" or "towards" and "phylaxis" (φύλαξις) meaning "guarding" or "protection".