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Vagal Maneuver
A vagal maneuver is an action used to stimulate the parasympathetic nervous system by activating the vagus nerve. The vagus nerve is the longest nerve of the autonomic nervous system and helps regulate many critical aspects of human physiology, including heart rate, blood pressure, sweating, and digestion through the release of acetylcholine. Common maneuvers that activate the vagus nerve include the Valsalva maneuver and carotid sinus massage, which can serve diagnostic or therapeutic functions. Clinical indications There are both diagnostic and therapeutic indications for the use of vagal maneuvers in clinical practice. Diagnostic: * Vagal maneuvers (most commonly the Valsalva maneuver) can be used to distinguish between ventricular tachycardia and supraventricular tachycardia by slowing the rate of conduction at the SA or AV nodes. * Vagal maneuvers (most commonly carotid sinus massage) are used to diagnose carotid sinus hypersensitivity. Therapeutic: * Vagal maneuvers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oculocardiac Reflex
The oculocardiac reflex, also known as Aschner phenomenon, Aschner reflex, or Aschner–Dagnini reflex, is a decrease in pulse rate associated with traction applied to extraocular muscles and/or compression of the eyeball. The reflex is mediated by nerve connections between the ophthalmic branch of the trigeminal cranial nerve via the ciliary ganglion, and the vagus nerve of the parasympathetic nervous system. Nerve fibres from the maxillary and mandibular divisions of the trigeminal nerve have also been documented. These afferents synapse with the visceral motor nucleus of the vagus nerve, located in the reticular formation of the brain stem. The efferent portion is carried by the vagus nerve from the cardiovascular center of the medulla to the heart, of which increased stimulation leads to decreased output of the sinoatrial node. This reflex is especially sensitive in neonates and children, particularly during strabismus correction surgery. Oculocardiac reflex can be prof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardiovascular Physiology
Cardiovascular physiology is the study of the cardiovascular system, specifically addressing the physiology of the heart ("cardio") and blood vessels ("vascular"). These subjects are sometimes addressed separately, under the names cardiac physiology and circulatory physiology. Although the different aspects of cardiovascular physiology are closely interrelated, the subject is still usually divided into several subtopics. Heart * Cardiac output (= heart rate * stroke volume. Can also be calculated with Fick principle,palpeting method.) ** Stroke volume (= end-diastolic volume − end-systolic volume) ** Ejection fraction (= stroke volume / end-diastolic volume) ** Cardiac output is mathematically ` to systole ** Inotropic, chronotropic, and dromotropic states ** Cardiac input (= heart rate * suction volume Can be calculated by inverting terms in Fick principle) ** Suction volume (= end-systolic volume + end-diastolic volume) ** Injection fraction (=suction volume / end- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemoreceptor Reflex
A chemoreceptor, also known as chemosensor, is a specialized sensory receptor which transduces a chemical substance ( endogenous or induced) to generate a biological signal. This signal may be in the form of an action potential, if the chemoreceptor is a neuron, or in the form of a neurotransmitter that can activate a nerve fiber if the chemoreceptor is a specialized cell, such as taste receptors, or an internal peripheral chemoreceptor, such as the carotid bodies. In physiology, a chemoreceptor detects changes in the normal environment, such as an increase in blood levels of carbon dioxide (hypercapnia) or a decrease in blood levels of oxygen (hypoxia), and transmits that information to the central nervous system which engages body responses to restore homeostasis. In bacteria, chemoreceptors are essential in the mediation of chemotaxis. Cellular chemoreceptors In prokaryotes Bacteria utilize complex long helical proteins as chemoreceptors, permitting signals to travel lon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baroreflex
The baroreflex or baroreceptor reflex is one of the body's homeostatic mechanisms that helps to maintain blood pressure at nearly constant levels. The baroreflex provides a rapid negative feedback loop in which an elevated blood pressure causes the heart rate to decrease. Decreased blood pressure decreases baroreflex activation and causes heart rate to increase and to restore blood pressure levels. Their function is to sense pressure changes by responding to change in the tension of the arterial wall The baroreflex can begin to act in less than the duration of a cardiac cycle (fractions of a second) and thus baroreflex adjustments are key factors in dealing with postural hypotension, the tendency for blood pressure to decrease on standing due to gravity. The system relies on specialized neurons, known as baroreceptors, chiefly in the aortic arch and carotid sinuses, to monitor changes in blood pressure and relay them to the medulla oblongata. Baroreceptors are stretch receptors and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vagus Nerve Stimulation
Vagus nerve stimulation (VNS) is a medical treatment that involves delivering electrical impulses to the vagus nerve. It is used as an add-on treatment for certain types of intractable epilepsy and treatment-resistant depression. Medical use VNS devices are used to treat drug-resistant epilepsy and treatment-resistant major depressive disorder (TR-MDD). In the United States, VNS is approved as adjunctive therapy for those 4 years of age or older with refractory focal onset seizures. In the European Union, VNS is approved as an adjunctive therapy for patients with either generalized or focal onset seizures without any age restrictions. It is recommended that VNS is only pursued following an adequate trial of at least 2 appropriately chosen anti-seizure medications and that the patient is ineligible for epilepsy surgery. This is because epilepsy surgery is associated with a higher probability of resulting in seizure freedom. Patients who have poor adherence or tolerance of ant ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solitary Nucleus
In the human brainstem, the solitary nucleus, also called nucleus of the solitary tract, nucleus solitarius, and nucleus tractus solitarii, (SN or NTS) is a series of purely sensory nuclei (clusters of nerve cell bodies) forming a vertical column of grey matter embedded in the medulla oblongata. Through the center of the SN runs the solitary tract, a white bundle of nerve fibers, including fibers from the facial, glossopharyngeal and vagus nerves, that innervate the SN. The SN projects to, among other regions, the reticular formation, parasympathetic preganglionic neurons, hypothalamus and thalamus, 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 receiving information from cardio-respiratory and gastrointestinal processes are found in the caudal part. Inputs * Taste information from the facial nerve via t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carotid Sheath
The carotid sheath is an anatomical term for the fibrous connective tissue that surrounds the vascular compartment of the neck. It is part of the deep cervical fascia of the neck, below the superficial cervical fascia meaning the subcutaneous adipose tissue immediately beneath the skin. The deep cervical fascia of the neck includes four parts: * The investing layer (encloses the SCM and Trapezius) * The carotid sheath (encloses the vascular region of the neck) * The pretracheal fascia (encloses the visceral region of the neck) * The prevertebral fascia (encloses the vertebral region of the neck) Structure The carotid sheath is located at the lateral boundary of the retropharyngeal space at the level of the oropharynx on each side of the neck and deep to the sternocleidomastoid muscle. It extends from the base of the skull to the first rib and sternum, varying between C7 and T4. It merges with the axillary sheath when it reaches the subclavian vein. Contents The four major st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jugular Foramen
A jugular foramen is one of the two (left and right) large foramina (openings) in the base of the skull, located behind the carotid canal. It is formed by the temporal bone and the occipital bone. It allows many structures to pass, including the inferior petrosal sinus, three cranial nerves, the sigmoid sinus, and meningeal arteries. Structure The jugular foramen is formed in front by the petrous portion of the temporal bone, and behind by the occipital bone. It is generally slightly larger on the right side than on the left side. Contents The jugular foramen may be subdivided into three compartments, each with their own contents. * The ''anterior'' compartment transmits the inferior petrosal sinus. * The ''intermediate'' compartment transmits the glossopharyngeal nerve, the vagus nerve, and the accessory nerve. * The ''posterior'' compartment transmits the sigmoid sinus (becoming the internal jugular vein), and some meningeal branches from the occipital artery and ascend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cranial Nerve X
The vagus nerve, also known as the tenth cranial nerve, cranial nerve X, or simply CN X, is a cranial nerve that interfaces with the parasympathetic control of the heart, lungs, and digestive tract. It comprises two nerves—the left and right vagus nerves—but they are typically referred to collectively as a single subsystem. The vagus is the longest nerve of the autonomic nervous system in the human body and comprises both sensory and motor fibers. The sensory fibers originate from neurons of the nodose ganglion, whereas the motor fibers come from neurons of the dorsal motor nucleus of the vagus and the nucleus ambiguus. The vagus was also historically called the pneumogastric nerve. Structure Upon leaving the medulla oblongata between the olive and the inferior cerebellar peduncle, the vagus nerve extends through the jugular foramen, then passes into the carotid sheath between the internal carotid artery and the internal jugular vein down to the neck, chest, and abdomen, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blausen 0703 Parasympathetic Innervation
Blausen Medical Communications, Inc. is the creator and owner of a library of two- and three-dimensional medical and scientific images and animations, a developer of information technology allowing access to that content, and a business focused on licensing and distributing the content. It was founded by Bruce Blausen in Houston, Texas, in 1991, and is privately held. Background Blausen Medical Communications, Inc. (BMC) is a privately held company founded by Bruce Blausen in Houston, Texas in 1991. BMC created and owns a library of medical and scientific images and animations, and has developed information technology tools allowing access to the library; as well, it licenses and otherwise works to distribute the content. As of this date, BMC's animation library comprised approximately 1,500 animations and over 27,000 two- and three-dimensional images designed for point-of-care patient education, which could be accessed by consumers or professional caregivers (primarily via ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
