Ventral respiratory group

The (VRG) is a column of neurons located in the ventrolateral region of the medulla, extending from the caudal facial nucleus to -400μm obex. The four cell groups of the VRG are the rostral nucleus retrofacialis, caudal nucleus retroambiguus, nucleus para-ambiguus, and the pre-Bötzinger complex.

Respiratory effects

The VRG contains both inspiratory and expiratory neurons. The VRG is secondarily responsible for initiation of inspiratory activity, after the dorsal respiratory group. The nucleus para-ambiguus is active during inspiration, while the nucleus retrofacialis and the nucleus retroambiguus are active during exhalation.

The VRG is responsible for motor control of inspiratory and expiratory muscles during exercise.

The pre-Bötzinger complex is the hypothesized location of central respiratory rhythm pattern generation circuitry. The pre-Bötzinger complex also contains pacemaker cells which initiate spontaneous breathing. It is currently unclear how this system regulates its output to effect motoneuron bursting, which in turn is responsible for inspiratory muscle innervation. Research into the function of the pre-Bötzinger complex is currently being studied by making use of the in vitro slice preparation.

External links

Overview at vcu.edu

References

Smith J, Ellenberger H, Ballanyi K, Richter D, Feldman J (1991). "Pre-Bötzinger complex: a brainstem region that may generate respiratory rhythm in mammals". Science 254 (5032): 726–9. doi:10.1126/science.1683005. PMC 3209964. PMID 1683005.

Berne, Robert M.; Levy, Matthew N.; Koeppen, Bruce M.; Stanton, Bruce A. (2004). Physiology, 5th edition. St. Louis, MO: Elsevier. pp. 513–4. ISBN 0-323-03390-3.

Respiratory physiology

Respiration	positive pressure ventilation breath (inhalation exhalation) respiratory rate respirometer pulmonary surfactant compliance elastic recoil hysteresivity airway resistance bronchial hyperresponsiveness bronchoconstriction/Bronchodilatation

Control	pons pneumotaxic center apneustic center medulla dorsal respiratory group ventral respiratory group chemoreceptors central peripheral pulmonary stretch receptors Hering–Breuer reflex

Lung volumes	VC FRC Vt dead space CC PEF calculations respiratory minute volume FEV1/FVC ratio methods of lung testing spirometry body plethysmography peak flow meter nitrogen washout

Circulation	pulmonary circulation hypoxic pulmonary vasoconstriction pulmonary shunt

Interactions	Perfusion (V) ventilation (V) ventilation/perfusion scan zones of the lung gas exchange pulmonary gas pressures alveolar gas equation alveolar–arterial gradient hemoglobin oxygen–haemoglobin dissociation curve (Oxygen saturation 2,3-BPG Bohr effect Haldane effect) carbonic anhydrase (chloride shift) oxyhemoglobin respiratory quotient arterial blood gas diffusion capacity (DLCO)

Insufficiency	high altitude oxygen toxicity hypoxia

Anatomy of the medulla

Grey matter

Cranial nuclei

afferent:	Solitary nucleus tract Dorsal respiratory group Gustatory nucleus Vestibular nuclei Lateral Medial Inferior

efferent:	Hypoglossal nucleus Nucleus ambiguus Dorsal nucleus of vagus nerve Inferior salivatory nucleus

Dorsal

Ventral

White matter

Dorsal	Sensory Sensory decussation Medial lemniscus Juxtarestiform body Ascending dorsal longitudinal fasciculus Medial longitudinal fasciculus Motor Descending dorsal longitudinal fasciculus Medial longitudinal fasciculus

Ventral	Descending tracts Olivocerebellar tract Rubro-olivary tract

Surface

Front	Pyramid decussation Anterior median fissure Anterolateral sulcus Olive Inferior olivary nucleus

Back	Posterior median sulcus Posterolateral sulcus Area postrema Vagal trigone Hypoglossal trigone Medial eminence Inferior cerebellar peduncle

Grey

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Ventral respiratory group

Respiratory effects

See also

External links

References