QS Study

Non-chemical Control of Respiration

The group of neurons in the brain which regulates the respiration rhythmically is collectively known as a respiratory centre. Respiratory system has the responsibility of meeting needs of the body by altering the rate and depth of respiration in order to keep the PO2 and PCO2 at normal levels. The medulla and the pons are involved in the regulation of the ventilatory pattern of respiration.

(i) Vagal afferents from receptors in the airways and lungs →↑ Respiration.

(ii) Afferents frond he pons, hypothalamus and limbic system →↑ Respiration.

(iii) Afferents from proprioceptors →↑ Respiration.

(iv) Afferents from bar receptors arterial ventricular and pulmonary →↓ Respiration.

Is non-chemical feedback vital in regulating the amplitude and timing of respiratory motor output in humans? Characteristically, breath holding experiments were used by Fowler (1954) to demonstrate that higher levels of CO2 could be tolerated in humans while breathing than while breath holding. More recently, non-chemical regulation of breathing in humans has been addressed by using mechanical ventilation to alter tidal volume (VT), breathing frequency, flow rate, and/or levels of pressure support.

Hormonal effects on respiration

Ventilation is increasing during the lateral phase of the menstrual cycle and during pregnancy. This is due to activation of estrogen-dependent progesterone in the hypothalamus.