toksina

Toksina is a poisonous substance produced by living organisms or occurring as a chemical toxin that can harm living beings upon exposure. The term covers natural substances as well as synthetic compounds. Toxins originate from bacteria, plants, fungi and animals, and can act locally or systemically.

Toxins are classified by origin (biotoxins) and by mechanism. Exotoxins are soluble proteins secreted by bacteria; endotoxins are components of bacterial cell walls released when cells die. Mycotoxins come from fungi, while plant and animal toxins include alkaloids and venoms. Clinically important categories include neurotoxins (affect nervous tissue), cytotoxins (kill or damage cells), hepatotoxins and cardiotoxins.

Exposure occurs by ingestion, inhalation, skin contact, or injection. Toxic effects depend on dose, route, and duration. The LD50 is a conventional measure of acute toxicity in animal studies.

Diagnosis relies on patient history and signs, with laboratory testing to identify the toxin or its metabolites when possible. Treatment emphasizes decontamination (for example, activated charcoal when indicated), supportive care, and, where available, specific antidotes, antitoxins or antivenoms. Some toxins require chelation, receptor blockade, or organ-supportive therapy. Prevention focuses on reducing exposure, safe handling of chemicals, proper food safety, vaccination where applicable, and regulatory controls.

Notable toxins include botulinum toxin, tetanus toxin, ricin, aflatoxins, saxitoxins and ciguatoxins, each with unique mechanisms. Understanding toksina and toxicology supports medicine, public health and safety.