Peripheral chemoreceptors are stimulated maximally by

Cyanide causes histotoxic hypoxia, and thus, by preventinng the O2 utilization at the tissue level; it acts as the powerful stimulus for peripheral chemoreceptors. Even though pO2 levels of blood is normal in case of cyanide poisoning the sensors in carotid and aoic bodies are not able to sense oxygen in blood because of blockade of cellular respiration and hence, they go in for hypoxic state and gets stimulated. Option A: Acidosis (Increased H+ ions) stimulates peripheral chemoreceptors. Option B: Increased pCO2 mainly stimulates central chemoreceptors. Option C: The peripheral chemoreceptors have an enormous bloodflow per unit tissue (2000mL/100g of tissue/min) because of which the O2 needs of the cells can be met by dissolved O2. Therefore, Carbonmonoxide poisoning doesnot stimulate peripheral chemoreceptors because the amount of dissolved O2 is generally normal, even though the combined O2 in the blood is markedly decreased. Ref: Ganong&;s Review of Medical Physiology 26th edition&; Pgno: 641