Biomaterial Database

The respiratory motoneuron and apneusis. 1977

T A Sears

A brief review is given of experimental studies on 'apneusis' (Lumsden) and the role these have played in the conceptual development of the ideas relating to the nervous mechanism of breathing. It is suggested that the terms "apneustic," "pneumotaxic," and "respiratory" (inspiratory or expiratory) centers should be abandoned in view of the convoluted epistemology of the concepts they represent. New experiments on expiratory apneusis are described, involving sagittal incisions of the brain stem in the vicinity of the obex, which have allowed study of the brain stem-mediated effects of CO2 on expiratory motoneurons, under steady-state conditions. These experiments reveal the existence of a CO2-dependent tonic excitation of expiratory motoneurons that, it is argued, depends on a simple pathway between peripheral and central chemoreceptors and expiratory bulbospinal neurons. The possible synaptic mechanisms underlying the production of CO2-dependent appneusis are discussed in relation to peripheral chemoreceptors and illustrated in relation to a model motoneuron.

UI	MeSH Term	Description	Entries
D006985	Hyperventilation	A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide.	Hyperventilations
D007367	Intercostal Nerves	The ventral rami of the thoracic nerves from segments T1 through T11. The intercostal nerves supply motor and sensory innervation to the thorax and abdomen. The skin and muscles supplied by a given pair are called, respectively, a dermatome and a myotome.	Intercostal Nerve,Nerve, Intercostal,Nerves, Intercostal
D008526	Medulla Oblongata	The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.	Accessory Cuneate Nucleus,Ambiguous Nucleus,Arcuate Nucleus of the Medulla,Arcuate Nucleus-1,External Cuneate Nucleus,Lateral Cuneate Nucleus,Nucleus Ambiguus,Ambiguus, Nucleus,Arcuate Nucleus 1,Arcuate Nucleus-1s,Cuneate Nucleus, Accessory,Cuneate Nucleus, External,Cuneate Nucleus, Lateral,Medulla Oblongatas,Nucleus, Accessory Cuneate,Nucleus, Ambiguous,Nucleus, External Cuneate,Nucleus, Lateral Cuneate
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D008959	Models, Neurological	Theoretical representations that simulate the behavior or activity of the neurological system, processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.	Neurologic Models,Model, Neurological,Neurologic Model,Neurological Model,Neurological Models,Model, Neurologic,Models, Neurologic
D009046	Motor Neurons	Neurons which activate MUSCLE CELLS.	Neurons, Motor,Alpha Motorneurons,Motoneurons,Motor Neurons, Alpha,Neurons, Alpha Motor,Alpha Motor Neuron,Alpha Motor Neurons,Alpha Motorneuron,Motoneuron,Motor Neuron,Motor Neuron, Alpha,Motorneuron, Alpha,Motorneurons, Alpha,Neuron, Alpha Motor,Neuron, Motor
D009433	Neural Inhibition	The function of opposing or restraining the excitation of neurons or their target excitable cells.	Inhibition, Neural
D011149	Pons	The front part of the hindbrain (RHOMBENCEPHALON) that lies between the MEDULLA and the midbrain (MESENCEPHALON) ventral to the cerebellum. It is composed of two parts, the dorsal and the ventral. The pons serves as a relay station for neural pathways between the CEREBELLUM to the CEREBRUM.	Pons Varolii,Ponte,Pons Varolius,Pontes,Varolii, Pons,Varolius, Pons
D011661	Pulmonary Stretch Receptors	Stretch receptors found in the bronchi and bronchioles. Pulmonary stretch receptors are sensors for a reflex which stops inspiration. In humans, the reflex is protective and is probably not activated during normal respiration.	Receptors, Pulmonary Stretch,Receptors, Stretch, Pulmonary,Stretch Receptors, Pulmonary,Lung Stretch Receptors,Receptors, Stretch, Lung,Stretch Receptors, Lung,Lung Stretch Receptor,Pulmonary Stretch Receptor,Receptor, Lung Stretch,Receptor, Pulmonary Stretch,Receptors, Lung Stretch,Stretch Receptor, Lung,Stretch Receptor, Pulmonary
D012119	Respiration	The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (	Breathing