Central respiratory center

The control of ventilation refers to the physiological mechanisms involved in the control of breathing, which is the movement of air into and out of the lungs. Ventilation facilitates respiration. Respiration refers to the utilization of oxygen and production of carbon dioxide by the body as a whole, or by individual cells in cellular respiration.

The most important function of breathing is the supplying of oxygen to the body and the removal of its waste product of carbon dioxide. Under most conditions, the partial pressure of carbon dioxide (PCO2) or concentration of carbon dioxide, controls the respiratory rate.

The sensors for the arterial blood gas regulator are situated in the aortic and carotid bodies, which are primarily sensitive to the partial pressure of oxygen (PO2) in the arterial blood, and the anterior and lateral surfaces of the medulla oblongata in the brainstem which measures the PCO2 and pH of the cerebrospinal fluid and consequently the arterial blood

Information from these sensors is conveyed along nerves to the respiratory centers in the brain stem. The respiratory centers are located in the medulla oblongata and the pons in the brainstem. There are four, two in the medulla and two in the pons.

From the respiratory centers the muscles of respiration, in particular the diaphragm, are alternately activated to cause air to move in and out of the lungs.

The pattern of motor stimuli during breathing can be divided into inspiratory and expiratory phases. Inspiration shows a sudden, ramped increase in motor discharge to the inspiratory muscles (including pharyngeal dilator muscles). Before the end of inspiration, there is a decline in motor discharge. Exhalation is usually silent, except at high minute ventilation rates.

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