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Parvocellular Reticular Nuclei
The parvocellular reticular nucleus is part of the brain located dorsolateral to the caudal pontine reticular nucleus. The dorsal portion of the reticular nucleus has been shown to innervate the mesencephalic trigeminal nucleus and its surrounding area. Also, it projects to the facial nucleus, hypoglossal nucleus and parabrachial area along with parts of the caudal parvocellular reticular formation.Ter Horst, GJ et al. Projections from the rostral parvocellular reticular formation to pontine and medullary nuclei in the rat: involvement in autonomic regulation and orofacial motor control. Neuroscience. 1991;40(3):735-58. This nucleus is also involved in expiration with a part of the gigantocellular nucleus The gigantocellular reticular nucleus (Gi) is a subregion of the medullary reticular formation. As the name indicates, it consists mainly of so-called giant neuronal cells. This nucleus has been known to innervate the caudal hypoglossal nucleus, .... References Medulla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a vertebrate's body. In a human, the cerebral cortex contains approximately 14–16 billion neurons, and the estimated number of neurons in the cerebellum is 55–70 billion. Each neuron is connected by synapses to several thousand other neurons. These neurons typically communicate with one another by means of long fibers called axons, which carry trains of signal pulses called action potentials to distant parts of the brain or body targeting specific recipient cells. Physiologically, brains exert centralized control over a body's other organs. They act on the rest of the body both by generating patterns of muscle activity and by driving the secretion of chemicals called hormones. This centralized control allows rapid and coordinated respon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caudal Pontine Reticular Nucleus
The caudal pontine reticular nucleus or nucleus reticularis pontis caudalis is a portion of the reticular formation, composed of gigantocellular neurons. In rabbits and cats it is exclusively giant cells, however in humans there are normally sized cells as well. In rodents, it has been shown to play a role in the acoustic startle response. The caudal pontine reticular nucleus is rostral to the gigantocellular reticular nucleus and is located in the caudal pons. The caudal pontine reticular nucleus has been known to mediate head movement, in concert with the gigantocellular nucleus and the superior colliculus. The neurons in the dorsal half of this nucleus fire rhythmically during mastication, and in an anesthetized animal it is possible to induce mastication via electrical stimulation of the nucleus reticularis pontis caudalis or adjacent areas of the gigantocellular nucleus.Scott G, Effect of lidocaine and NMDA injections into the medial pontobulbar reticular formation on mast ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mesencephalic Trigeminal Nucleus
The mesencephalic nucleus of trigeminal nerve is involved with reflex proprioception of the periodontium and of the muscles of mastication in the jaw that functions to prevent biting down hard enough to lose a tooth. To subserve this reflex protective function, mechanoreceptive nerves in the periodontal ligament sense tooth movement and project to the mesencephalic nucleus. Likewise, afferent fibers from muscle spindles, the sensory organs of skeletal muscle, are stimulated by the stretch of hard contraction of jaw muscles. The temporomandibular joint receptors and the Golgi tendon organs of the jaw muscles do not project to the mesencephalic nucleus. The mesencephalic nucleus is one of four trigeminal nerve nuclei, three sensory and one motor. The other two sensory nuclei are the chief sensory nucleus mediating conscious facial touch and the spinal trigeminal nucleus, mediating pain and temperature in the head, and is of importance in headache. The trigeminal motor nucleus innervate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Facial Nucleus
The facial motor nucleus is a nucleus (neuroanatomy), collection of neurons in the brainstem that belong to the facial nerve (cranial nerve VII). These lower motor neurons innervate the muscles of facial expression and the stapedius. Structure The Nucleus (neuroanatomy), nucleus is situated in the caudal portion of the ventrolateral pontine tegmentum. Its axons take an unusual course, traveling dorsally and looping around the abducens nucleus, then traveling ventrally to exit the basilar part of the pons, ventral pons medial to the spinal trigeminal nucleus. These axons form the motor component of the facial nerve, with parasympathetic nervous system, parasympathetic and sensory fiber, sensory components forming the intermediate nerve. The nucleus has a dorsal and ventral region, with neurons in the dorsal region innervating muscles of the upper face and neurons in the ventral region innervating muscles of the lower face. Function Because it innervates muscles derived from pharyn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypoglossal Nucleus
The hypoglossal nucleus is a cranial nerve nucleus, found within the medulla oblongata, medulla. Being a motor nucleus, it is close to the midline. In the Medulla oblongata#Anatomy, open medulla, it is visible as what is known as the ''hypoglossal trigone'', a raised area (medial to the vagal trigone) protruding slightly into the fourth ventricle. The hypoglossal nucleus is located between the Dorsal nucleus of vagus nerve, dorsal motor nucleus of the vagus and the midline of the medulla. Axons from the hypoglossal nucleus pass anteriorly through the medulla forming the hypoglossal nerve which exits between the Medullary pyramids (brainstem), pyramid and Olivary body, olive in a groove called the Anterolateral sulcus of medulla, anterolateral sulcus. See also * Hypoglossal nerve Additional images File:Gray695.png, Transverse section of medulla oblongata below the middle of the olive. File:Gray697.png, Nuclei of origin of cranial motor nerves schematically represented; lateral v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parabrachial Area
The parabrachial nuclei, also known as the parabrachial complex, are a group of nuclei in the dorsolateral pons that surrounds the superior cerebellar peduncle as it enters the brainstem from the cerebellum. They are named from the Latin term for the superior cerebellar peduncle, the ''brachium conjunctivum''. In the human brain, the expansion of the superior cerebellar peduncle expands the parabrachial nuclei, which form a thin strip of grey matter over most of the peduncle. The parabrachial nuclei are typically divided along the lines suggested by Baxter and Olszewski in humans, into a medial parabrachial nucleus and lateral parabrachial nucleus. These have in turn been subdivided into a dozen subnuclei: the superior, dorsal, ventral, internal, external and extreme lateral subnuclei; the lateral crescent and subparabrachial nucleus (Kolliker-Fuse nucleus) along the ventrolateral margin of the lateral parabrachial complex; and the medial and external medial subnuclei Componen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Exhalation
Exhalation (or expiration) is the flow of the breath out of an organism. In animals, it is the movement of air from the lungs out of the airways, to the external environment during breathing. This happens due to elastic properties of the lungs, as well as the internal intercostal muscles which lower the rib cage and decrease thoracic volume. As the thoracic diaphragm relaxes during exhalation it causes the tissue it has depressed to rise superiorly and put pressure on the lungs to expel the air. During forced exhalation, as when blowing out a candle, expiratory muscles including the abdominal muscles and internal intercostal muscles generate abdominal and thoracic pressure, which forces air out of the lungs. Exhaled air is 4% carbon dioxide, a waste product of cellular respiration during the production of energy, which is stored as ATP. Exhalation has a complementary relationship to inhalation which together make up the respiratory cycle of a breath. Exhalation and gas e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gigantocellular Nucleus
The gigantocellular reticular nucleus (Gi) is a subregion of the medullary reticular formation. As the name indicates, it consists mainly of so-called giant neuronal cells. This nucleus has been known to innervate the caudal hypoglossal nucleus, and responds to glutamatergic stimuli. The gigantocellular nucleus excites the hypoglossal nucleus, and can play a role in the actions of the said nerve.Yang, CC et al. Excitatory innervation of caudal hypoglossal nucleus from nucleus reticularis gigantocellularis in the rat. Neuroscience. 1995 Mar;65(2):365-74. It additionally receives connections from the periaqueductal gray, the paraventricular hypothalamic nucleus, central nucleus of the amygdala, lateral hypothalamic area, and parvocellular reticular nucleus. Retrograde studies have shown that the deep mesencephalic reticular formation and oral pontine reticular nucleus project to the gigantocellular nucleus. The dorsal rostral section of the nucleus reticularis gigantocellularis is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
