Some toxins are deadly because they interfere with oxygen availability or use within the body. Oxygen diffuses from the alveoli into the pulmonary capillaries, where it binds to haemoglobin in the blood and is transported to cells throughout the body. Toxicants that interfere with components of the respiration pathway are following:
Inert Gases – Displace oxygen from inspired air (asphyxiation)
Opioids– CNS respiratory centre, which controls respiratory muscles, is depressed (respiratory failure)
Succinylcholine – Muscles of the lungs are paralysed (respiratory failure)
Strychnine – Causes the respiratory muscles to contract for an extended period of time (respiratory failure)
Carbon Monoxide – Binds to haemoglobin, preventing oxygen delivery and binding.
Cyanide – Prevents the transport of oxygen from haemoglobin to cells.
Poisons : an introduction for forensic investigators by David J.
Brooks M: Knockout gas: Chemical weapon in disguise. New Scientist, October 20,
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