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Petrous Ganglion
The inferior ganglion of the glossopharyngeal nerve (petrosal ganglion) is a sensory ganglion. It is larger than and inferior to the superior ganglion of the glossopharyngeal nerve. It is located within the jugular foramen. The pseudounipolar neurons of the inferior ganglion of the glossopharyngeal nerve provide sensory innervation to areas around the tongue and pharynx. More specifically: # innervation of taste buds on the posterior 1/3 of tongue # general sensory innervation of posterior 1/3 of tongue, soft palate, palatine tonsils, upper pharynx and Eustachian tubes # innervation of baroreceptor cells in the carotid sinus # innervation of glomus type I chemoreceptor cells in the carotid body The central processes of the neurons which provide taste sensation synapse in the rostral portion of the solitary nucleus (also called the gustatory nucleus). The central processes of the neurons which provide general sensory information synapse in the spinal trigeminal nucleus. Finally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossopharyngeal
The glossopharyngeal nerve (), also known as the ninth cranial nerve, cranial nerve IX, or simply CN IX, is a cranial nerve that exits the brainstem from the sides of the upper Medulla oblongata, medulla, just anterior (closer to the nose) to the vagus nerve. Being a mixed nerve (sensorimotor), it carries afferent sensory and efferent motor information. The motor division of the glossopharyngeal nerve is derived from the Basal plate (neural tube), basal plate of the embryonic medulla oblongata, whereas the sensory division originates from the cranial neural crest. Structure From the anterior portion of the medulla oblongata, the glossopharyngeal nerve passes laterally across or below the Flocculus (cerebellar), flocculus, and leaves the skull through the central part of the jugular foramen. From the superior and inferior ganglia in jugular foramen, it has its own sheath of dura mater. The inferior ganglion on the inferior surface of petrous part of temporal is related with a tri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eustachian Tube
The Eustachian tube (), also called the auditory tube or pharyngotympanic tube, is a tube that links the nasopharynx to the middle ear, of which it is also a part. In adult humans, the Eustachian tube is approximately long and in diameter. It is named after the sixteenth-century Italian anatomist Bartolomeo Eustachi. In humans and other tetrapods, both the middle ear and the ear canal are normally filled with air. Unlike the air of the ear canal, however, the air of the middle ear is not in direct contact with the atmosphere outside the body; thus, a pressure difference can develop between the atmospheric pressure of the ear canal and the middle ear. Normally, the Eustachian tube is collapsed, but it gapes open with swallowing and with positive pressure, allowing the middle ear's pressure to adjust to the atmospheric pressure. When taking off in an aircraft, the ambient air pressure goes from higher (on the ground) to lower (in the sky). The air in the middle ear expands as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inferior Salivatory Nucleus
The salivatory nuclei are two general visceral efferent nuclei located in the caudal pons, dorsal and lateral to the facial nucleus. Their neurons give rise to preganglionic parasympathetic nerve fibers in the control of salivation.Digital version The superior salivatory nucleus supplies fibers to the intermediate nerve (part of the facial nerve (CN VII). The inferior salivatory nucleus supplies fibers to the glossopharyngeal nerve (CN IX). The nuclei may also be involved in parasympathetic control of (extracranial and intracranial) head vasculature. Superior salivatory nucleus The superior salivatory nucleus (or nucleus salivatorius superior) is a visceral motor cranial nerve nucleus of the facial nerve (CN VII). It is located in the pontine tegmentum. It projects pre-ganglionic visceral motor parasympathetic efferents (via CN VII) to the pterygopalatine ganglion, and submandibular ganglion. The term "lacrimal nucleus" is sometimes used to refer to a portion of the superio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tympanic Nerve
The tympanic nerve ( Jacobson's nerve) is a branch of the glossopharyngeal nerve passing through the petrous part of the temporal bone to reach the middle ear. It provides sensory innervation for the middle ear, the Eustachian tube, the parotid gland, and mastoid cells. It also carries parasympathetic fibers destined for the parotid gland. Structure The tympanic nerve contains sensory axons to the middle ear (including the internal surface of the tympanic membrane) whose cell bodies are lodged in the superior ganglion of the glossopharyngeal nerve. It also contains parasympathetic axons which continue as the lesser petrosal nerve to the otic ganglion, which itself gives off postganglionic parasympathetic neurons. Origin The tympanic nerve arises from the inferior ganglion of the glossopharyngeal nerve (CN IX) in the jugular fossa. Course It passes through the petrous part of the temporal bone within the tympanic canaliculus that is situated within the bony ridge ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinal Trigeminal Nucleus
The spinal trigeminal nucleus is a nucleus in the medulla that receives information about deep/crude touch, pain, and temperature from the ipsilateral face. In addition to the trigeminal nerve (CN V), the facial (CN VII), glossopharyngeal (CN IX), and vagus nerves (CN X) also convey pain information from their areas to the spinal trigeminal nucleus. Thus the spinal trigeminal nucleus receives afferents from V, VII, [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gustatory Nucleus
The gustatory nucleus is the rostral part of the solitary nucleus located in the medulla oblongata. The gustatory nucleus is associated with the sense of taste and has two sections, the rostral and lateral regions. A close association between the gustatory nucleus and visceral information exists for this function in the gustatory system, assisting in homeostasis - via the identification of food that might be possibly poisonous or harmful for the body. There are many gustatory nuclei in the brain stem. Each of these nuclei corresponds to three cranial nerves, the facial nerve (VII), the glossopharyngeal nerve (IX), and the vagus nerve (X) and GABA is the primary inhibitory neurotransmitter involved in its functionality. All visceral afferents in the vagus and glossopharyngeal nerves first arrive in the nucleus of the solitary tract and information from the gustatory system can then be relayed to the thalamus and cortex. The central axons on primary sensory neurons in the taste sys ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solitary Nucleus
The solitary nucleus (SN) (nucleus of the solitary tract, nucleus solitarius, or nucleus tractus solitarii) is a series of neurons whose cell bodies form a roughly vertical column of grey matter in the medulla oblongata of the brainstem. Their axons form the bulk of the enclosed solitary tract. The solitary nucleus can be divided into different parts including dorsomedial, dorsolateral, and ventrolateral subnuclei. The solitary nucleus receives general visceral and special visceral inputs from the facial nerve (CN VII), glossopharyngeal nerve (CN IX) and vagus nerve (CN X); it receives and relays stimuli related to taste and visceral sensation. It sends outputs to various parts of the brain, such as the hypothalamus, thalamus, and reticular formation, forming circuits that contribute to autonomic regulation. Cells along the length of the SN are arranged roughly in accordance with function; for instance, cells involved in taste are located in the rostral part, while those rec ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Body
The carotid body is a small cluster of peripheral chemoreceptor cells and supporting sustentacular cells situated at the bifurcation of each common carotid artery in its tunica externa. The carotid body detects changes in the composition of arterial blood flowing through it, mainly the partial pressure of arterial oxygen, but also of carbon dioxide. It is also sensitive to changes in blood pH, and temperature. Structure The carotid body is situated on the posterior aspect of the bifurcation of the common carotid artery. The carotid body is made up of two types of cells, called glomus cells: glomus type I cells are peripheral chemoreceptors, and glomus type II cells are sustentacular supportive cells. * Glomus type I cells are derived from the neural crest. They release a variety of neurotransmitters, including acetylcholine, ATP, and dopamine that trigger EPSPs in synapsed neurons leading to the respiratory center. They are innervated by axons of the glossopharyngeal n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glomus Type I Cell
Glomus cells are the cell type mainly located in the carotid bodies and aortic bodies. Glomus type I cells are peripheral chemoreceptors which sense the oxygen, carbon dioxide and pH levels of the blood. When there is a decrease in the blood's pH, a decrease in oxygen (pO2), or an increase in carbon dioxide ( pCO2), the carotid bodies and the aortic bodies signal the dorsal respiratory group in the medulla oblongata to increase the volume and rate of breathing. The glomus cells have a high metabolic rate and good blood perfusion and thus are sensitive to changes in arterial blood gas tension. Glomus type II cells are sustentacular cells having a similar supportive function to glial cells. Structure The signalling within the chemoreceptors is thought to be mediated by the release of neurotransmitters by the glomus cells, including dopamine, noradrenaline, acetylcholine, substance P, vasoactive intestinal peptide and enkephalins. Vasopressin has been found to inhibit the response ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Sinus
In human anatomy, the carotid sinus is a dilated area at the base of the internal carotid artery just superior to the bifurcation of the internal carotid and external carotid at the level of the superior border of thyroid cartilage. The carotid sinus extends from the bifurcation to the "true" internal carotid artery. The carotid sinuses are sensitive to pressure changes in the arterial blood at this level. They are two out of the four baroreception sites in humans and most mammals. Structure The carotid sinus is the reflex area of the carotid artery, consisting of baroreceptors which monitor blood pressure. Function The carotid sinus contains numerous baroreceptors which function as a "sampling area" for many homeostatic mechanisms for maintaining blood pressure. The carotid sinus baroreceptors are innervated by the carotid sinus nerve, which is a branch of the glossopharyngeal nerve (CN IX). The neurons which innervate the carotid sinus centrally project to the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Palatine Tonsil
Palatine tonsils, commonly called the tonsils and occasionally called the faucial tonsils, are tonsils located on the left and right sides at the back of the throat in humans and other mammals, which can often be seen as flesh-colored, pinkish lumps. Tonsils only present as "white lumps" if they are inflamed or infected with symptoms of exudates (pus drainage) and severe swelling. Tonsillitis is an inflammation of the tonsils and will often, but not necessarily, cause a sore throat and fever. In chronic cases, tonsillectomy may be indicated. Structure The palatine tonsils are located in the isthmus of the fauces, between the palatoglossal arch and the palatopharyngeal arch of the soft palate. The palatine tonsil is one of the mucosa-associated lymphoid tissues (MALT), located at the entrance to the upper respiratory and gastrointestinal tracts to protect the body from the entry of exogenous material through mucosal sites. In consequence it is a site of, and potentia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus
The vagus nerve, also known as the tenth cranial nerve (CN X), plays a crucial role in the autonomic nervous system, which is responsible for regulating involuntary functions within the human body. This nerve carries both sensory and motor fibers and serves as a major pathway that connects the brain to various organs, including the heart, lungs, and digestive tract. As a key part of the parasympathetic nervous system, the vagus nerve helps regulate essential involuntary functions like heart rate, breathing, and digestion. By controlling these processes, the vagus nerve contributes to the body's "rest and digest" response, helping to calm the body after stress, lower heart rate, improve digestion, and maintain homeostasis. The vagus nerve consists of two branches: the right and left vagus nerves. In the neck, the right vagus nerve contains approximately 105,000 fibers, while the left vagus nerve has about 87,000 fibers, according to one source. However, other sources report slig ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
