Integrative Cardiovascular Control by Pulmonary Inflation Reflexes*
Irving H. Zucker, Joseph P. Gilmore in Reflex Control of the Circulation, 2020
Studies in humans have shown that pulmonary inflation reflexes exist but are less important than in experimental animals. Several studies in humans have failed to elicit reflex vasodilation with a deep breath or lung inflation (Wilson et al., 1988; Ott et al., 1975). However, there have been reports demonstrating in humans that increasing inflation or chemical stimulation of pulmonary receptors will have a negative inotropic effect suggesting that the general pathways of decreases in sympathetic tone causing cardiac depression (Kilburn and Sieker, 1960; Cassidy et al., 1979b) and peripheral hypotension and vasodilation also exist in humans (Schroeder and Loss, 1953; Jain et al., 1972) as have been demonstrated most clearly in experimental animals. The Hering-Breuer reflex can be elicited in humans (Gautier et al., 1981; Guz et al., 1964; Widdicombe, 1961; Hamilton et al., 1988), but is clearly weaker than the reflex responses in experimental animals. Thus, it remains to be determined whether pulmonary inflation reflexes may have a more potent control in disease states, or whether like the Bainbridge reflex can be demonstrated in humans, but has lost considerable potency in the evolution to humans (Boettcher et al., 1982).
Anatomy and Physiology of the Autonomic Nervous System
Kenneth J. Broadley in Autonomic Pharmacology, 2017
The medullary respiratory centre consists of the inspiratory centre located medially in the reticular formation and the expiratory centre located more laterally. A higher pneumotaxic centre in the reticular formation of the pons regulates the rhythmic nature of inspiration and expiration by turning off inspiration. The most important regulator of the respiratory centres is discharge from chemoreceptors located in the medulla, a rise in pCO2 causing an increase in the rate of ventilation. A rise in H+ concentration also stimulates ventilation, as does a fall in pO2 detected by carotid body chemoreceptors. The activity of the respiratory centre is also modified by afferent vagal impulses from stretch receptors in the bronchial tree, especially the smaller branches. When the lungs expand during inspiration the nerve traffic to the inspiratory centre increases until inspiration is brought to a halt. This is known as the Hering-Breuer reflex. In anaesthetized animals, section of the vagal nerves results in prolonged inspiration.
Maternal and neonatal physiology
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal in Principles of Physiology for the Anaesthetist, 2015
Chest wall muscle spindles are important mechanoreceptors that detect forces applied to the chest wall, and workload. The large airways have receptors that sense lung inflation and deflation and changes in the interstitial lung fluid. The Hering– Breuer reflex is evoked by gradual inflation of the lungs and results in a transient apnoea following inflation. Apnoeic spells lasting 5 seconds normally occur five to six times an hour, and this risk decreases at 52–60 weeks after gestation. Apnoeic spells lasting longer than 15 seconds and associated with bradycardia and cyanosis are regarded as significant.
Acute respiratory distress syndrome (ARDS) caused by the novel coronavirus disease (COVID-19): a practical comprehensive literature review
Published in Expert Review of Respiratory Medicine, 2021
Francisco Montenegro, Luis Unigarro, Gustavo Paredes, Tatiana Moya, Ana Romero, Liliana Torres, Juan Carlos López, Fernando Esteban Jara González, Gustavo Del Pozo, Andrés López-Cortés, Ana M Diaz, Eduardo Vasconez, Doménica Cevallos-Robalino, Alex Lister, Esteban Ortiz-Prado
A second possibility is related to self-inflicted patient lung injury (P-SILI) caused by the respiratory effort made by patients with respiratory failure when breathing spontaneously or with the support of noninvasive mechanical ventilation (NIMV), since the high respiratory impulse generates large tidal volumes (VT) with potential to cause transpulmonary pressure changes. Zones closed by lung damage are temporarily opened and closed again, generating stress injury (pressure changes) and strain injury (changes by deformation), which is known as a ‘Pendelluft phenomenon’ [33]. The different forces generated by muscular work cause damage to already injured lungs, increasing vascular leakage by increasing transmural pulmonary vascular pressure. The high respiratory drive may be due to increased stimulation of juxtacapillary receptors or inhibition of slowly adapting pulmonary stretch receptors (Hering-Breuer reflex) [34].
Related Knowledge Centers
- Action Potential
- Central Nervous System
- Pons
- Pulmonary Stretch Receptors
- Reflex
- Lung
- Inhalation
- Myelin
- Vagus Nerve
- Respiratory Center