Carotid Bodies - The functioning units of the Hypoxic Drive

As mentioned before, the Hypoxic Drive is regulated by the peripheral chemoreceptors located in Carotid bodies. In fact, the carotid bodies are integral in the sensing of systemic hypoxia and then activating the reflex of Hypoxic Driven ventilation. Carotid bodies are unique in that they respond instantaneously to even a moderate drop in peripheral oxygen (PO₂) levels. (Prabhakar , p 17) The carotid bodies are released bilaterally in the body and mainly in the carotid arteries where they are allowed to sense Hypoxic before it becomes a stimulus for the central nervous system. One of the fine functions of carotid bodies is that it can sense a stimulus in a very small range. For example, a change of between 100 and 180 torr in oxygen pressure will activate the nerves within carotid bodies. This is on a far smaller scale than other chemoreceptors. 

The diagram above shows the carotid body locations above the myo-cardial area. The carotid bodies are what contain the Peripheral chemo-receptors in a certain concentration that is regulated by the brain. There are peripheral chemo-receptors elsewhere in the body as well.