One thing to notice is that there are no peripheral oxygen chemoreceptors in framework of chemoreception that pertains to the medulla oblongata. Thus, there would not be a direct route for neurotransmission of peripheral oxygen chemoreceptors as do the carbon dioxide chemoreceptors located by the medulla oblongata which is connected to the brain. Overall, the chemoreceptors are the integral components that relate to both respiratory systems. Knowledge of how chemoreceptors function and work with action potentials, their processing, monitoring, limitations, and also the points at which they activate reflexes and respiratory neurotransmissions allows for a three dimensional view to be established as to how the body uses the two respiratory drives. Chemoreceptors are the materials that delegate the power of the Hypoxic Drive and how effective it is.


Above is a picture of the way neurotransmission is induced by blood CO2 levels. 

Carbon Dioxide Regulation by Normal Respiration

Going back to the carbon dioxide regulation, the Medulla Oblongata, a sector of the brain that controls autonomous reactions in the body, is responsible for monitoring the carbon dioxide levels and pressure. Once the medulla oblongata sees retention of carbon dioxide past normal pressures, the medulla oblongata activates respiratory reflex loops. This will in turn lead to inspiration to restore the balance or homeostatic conditions of the arterial blood gasses. The chemoreceptors that are controlled by the Medulla oblongata are indeed Carbon dioxide chemoreceptors. It is generally stated that since the medulla oblongata is bathed in carbon dioxide, it is able to use the carbon dioxide chemoreceptors within that specific area to easily monitor the transitory carbon dioxide levels. The medulla oblongata tracks the gas levels in order to make sure that acidity will be controlled. Acidity in the body is important because of the sole reason that the acids and bases in the body retain the ability to control all metabolic activities in the body. (A.C.F.A.S.P. 2009, p 2)

Note that the information here pertains to the normal Carbon Dioxide regulation and not through Chemoreception of peripheral chemoreceptors. There is a big difference as there is a Medulla Oblongata for normal CO2 regulation

Here is a picture of the Human upper body. The Medulla Oblongata is just under the brain and is where the regulation occurs with our primary carbon dioxide regulatory system( respiratory system).

Carotid Body Function and Unique Characteristics

Once the chemoreceptors pick up the trace of O₂ deprivation, they release neurotransmitters. These neurotransmitters in turn set off a chain of reactions that cause the body to release stored ATP and AMPK that will allow for the body to restore functions. (Wyatt, Mustard, and others, p 282) In essence, ATP and AMPK are the compounds in our body that are essential to body functions and processes that occur throughout every microcell of our body. (Khakh and Burnstock) The carotid body sensing is significantly different from normally used Carbon dioxide chemoreceptors. Carbon dioxide chemoreceptors are located in brain stem, coronary arteries and in carotid bodies as well. However, the major difference between the carbon dioxide chemoreceptors and the oxygen chemoreceptors is that the carbon dioxide chemoreceptors react to changes on a far more optimized level in the sense that they induce major alveolar ventilation with sensation of extraneous levels of carbon dioxide within the body. (Dean and Nattie 2010) The point in the making is that oxygen chemoreceptors can pick up the slightest drops; however, they do not introduce or rather initialize or catalyze a reaction until the oxygen pressure drops below an approximated 60 torr. The problem with an oxygen pressure below 60 torr is that the pressure is dubbed as Hypercapnic respiratory failure which is detrimental to the cellular functions of the body and the brain itself.




Above is a picture of AMPK and its uses within the body. The main elemental nature of AMPK is that it provides the power for protein synthesis which esentially drives the cellular functions of the body.

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.