<prompt> Cyanide poisoning causesStagnant anoxiaAnemic anoxiaHistotoxic anoxiaAnoxic anoxia  <response>: Anoxia According to Gordon 1944 the stoppage of vital functions depend upon tissue anoxia. Anoxia means lack of oxygen. It may be: 1 Anoxic anoxia: In this type, oxygen cannot reach the blood, because of lack of oxygen in the lungs. This occurs: a from breathing in a contaminated atmosphere, e.g., from exposure to the fumes in wells and tanks, or from exposure to sewer gas, b from mechanical interference with the passage of air into or down the respiratory tract, e.g., in smothering, choking, hanging, strangulation, drowning, traumatic asphyxia and ceain forms of acute poisoning. 2 Anaemic anoxia: In this type, oxygen-carrying capacity of the blood is reduced, e.g., acute massive haemorrhage, poisoning by carbon monoxide, chlorates, nitrates, coaltar derivatives. 3 Stagnant anoxia: In this type, impaired circulation results in a reduction of oxygen delivery to the tissues, e.g., hea failure, embolism and shock. 4 Histotoxic anoxia: In this type, the enzymatic processes by which the oxygen in the blood is used by the tissues are blocked, e.g., acute cyanide poisoning. Ref:- k s narayan reddy; pg num:-137 