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Gag Reflex
The pharyngeal reflex or gag reflex is a reflex muscular contraction of the back of the throat, evoked by touching the roof of the mouth, the back of the tongue, the area around the tonsils, the uvula, and the back of the throat. It, along with other aerodigestive reflexes such as reflexive pharyngeal swallowing, prevents objects in the oral cavity from entering the throat except as part of normal swallowing and helps prevent choking, and is a form of coughing. The pharyngeal reflex is different from the laryngeal spasm, which is a reflex muscular contraction of the vocal cords. Reflex arc In a reflex arc, a series of physiological steps occur very rapidly to produce a reflex. Generally a sensory receptor receives an environmental stimulus, in this case from objects reaching nerves in the back of the throat, and sends a message via an afferent nerve to the central nervous system (CNS). The CNS receives this message and sends an appropriate response via an efferent nerve (also known a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflex
In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs via neural pathways in the nervous system called reflex arcs. A stimulus initiates a neural signal, which is carried to a synapse. The signal is then transferred across the synapse to a motor neuron which evokes a target response. These neural signals do not always travel to the brain, so many reflexes are an automatic response to a stimulus that does not receive or need conscious thought. Many reflexes are fine-tuned to increase organism survival and self-defense. This is observed in reflexes such as the startle reflex, which provides an automatic response to an unexpected stimuli, and the feline righting reflex, which reorients a cat's body when falling to ensure safe landing. The simplest type of reflex, a short-latency reflex, has a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sword Swallowing
Sword swallowing is a skill in which the performer passes a sword through the mouth and down the esophagus to the stomach. This feat is not swallowing in the traditional sense. The natural processes that constitute swallowing do not take place, but are repressed to keep the passage from the mouth to the stomach open for the sword. The practice is dangerous and there is risk of injury or death. History Sword swallowing spread to Greece and Rome in the 1st century AD and to China in the 8th century. In Japan, it became a part of the Japanese acrobatic theatre, Sangaku, which included fire eating, tightrope walking, juggling and early illusion. In Europe, it developed into yet a third distinct type of performance associated with the medieval jongleurs, that of the street performance. Sword swallowing was performed during the Middle Ages as part of street theatre and was popular at festivals and other large gatherings. It began to die out in the mid-19th century and was outlawed in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Retching
Retching (also known as dry heaving) is the reverse movement (retroperistalsis) of the stomach and esophagus without vomiting. It can be caused by bad smells or choking, or by withdrawal from certain medications, or after vomiting has completed. Retching can also occur as a result of an emotional response or from stress, which produces the same physical reaction. The function is thought to be mixing gastric contents with intestinal refluxate in order to buffer the former and give it momentum in preparation of vomiting. Treatments include medication and correction of the fluid and electrolyte balance. Physiology The retching phase is characterized by a series of violent spasmodic abdomino-thoracic contractions with the glottis closed. During this time, the inspiratory (inhalatory) movements of the chest wall and diaphragm are opposed by the expiratory contractions of the abdominal musculature. At the same time, movements of the stomach and its contents take place. Whereas a patien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glottis
The glottis is the opening between the vocal folds (the rima glottidis). The glottis is crucial in producing vowels and voiced consonants. Etymology From Ancient Greek ''γλωττίς'' (glōttís), derived from ''γλῶττα'' (glôtta), variant of ''γλῶσσα'' (glôssa, "tongue"). Function Phonation As the vocal folds vibrate, the resulting vibration produces a "buzzing" quality to the speech, called voice or voicing or pronunciation. Sound production that involves moving the vocal folds close together is called ''glottal''. English has a voiceless glottal transition spelled "h". This sound is produced by keeping the vocal folds spread somewhat, resulting in non-turbulent airflow through the glottis. In many accents of English the glottal stop (made by pressing the folds together) is used as a variant allophone of the phoneme (and in some dialects, occasionally of and ); in some languages, this sound is a phoneme of its own. Skilled players of the Australian di ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pharynx
The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its structure varies across species. The pharynx carries food and air to the esophagus and larynx respectively. The flap of cartilage called the epiglottis stops food from entering the larynx. In humans, the pharynx is part of the digestive system and the conducting zone of the respiratory system. (The conducting zone—which also includes the nostrils of the nose, the larynx, trachea, bronchi, and bronchioles—filters, warms and moistens air and conducts it into the lungs). The human pharynx is conventionally divided into three sections: the nasopharynx, oropharynx, and laryngopharynx. It is also important in vocalization. In humans, two sets of pharyngeal muscles form the pharynx and determine the shape of its lumen. They are arranged as an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Larynx
The larynx (), commonly called the voice box, is an organ in the top of the neck involved in breathing, producing sound and protecting the trachea against food aspiration. The opening of larynx into pharynx known as the laryngeal inlet is about 4–5 centimeters in diameter. The larynx houses the vocal cords, and manipulates pitch and volume, which is essential for phonation. It is situated just below where the tract of the pharynx splits into the trachea and the esophagus. The word ʻlarynxʼ (plural ʻlaryngesʼ) comes from the Ancient Greek word ''lárunx'' ʻlarynx, gullet, throat.ʼ Structure The triangle-shaped larynx consists largely of cartilages that are attached to one another, and to surrounding structures, by muscles or by fibrous and elastic tissue components. The larynx is lined by a ciliated columnar epithelium except for the vocal folds. The cavity of the larynx extends from its triangle-shaped inlet, to the epiglottis, and to the circular outlet at the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brain Death
Brain death is the permanent, irreversible, and complete loss of brain function which may include cessation of involuntary activity necessary to sustain life. It differs from persistent vegetative state, in which the person is alive and some autonomic functions remain. It is also distinct from comas as long as some brain and bodily activity and function remain, and it is also not the same as the condition locked-in syndrome. A differential diagnosis can medically distinguish these differing conditions. Brain death is used as an indicator of legal death in many jurisdictions, but it is defined inconsistently and often confused by the public. Various parts of the brain may keep functioning when others do not anymore, and the term "brain death" has been used to refer to various combinations. For example, although one major medical dictionary considers "brain death" to be synonymous with "cerebral death" (death of the cerebrum), the US National Library of Medicine Medical Subject ... [...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 abdom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glossopharyngeal Nerve
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] |
Acupuncture
Acupuncture is a form of alternative medicine and a component of traditional Chinese medicine (TCM) in which thin needles are inserted into the body. Acupuncture is a pseudoscience; the theories and practices of TCM are not based on scientific knowledge, and it has been characterized as quackery. There is a range of acupuncture variants which originated in different philosophies, and techniques vary depending on the country in which it is performed, but can be divided into two main foundational philosophical applications and approaches, the first being the modern standardized form called eight principles TCM and the second an older system that is based on the ancient Daoist '' wuxing'', better known as the five elements or phases in the West. Acupuncture is most often used to attempt pain relief, though acupuncturists say that it can also be used for a wide range of other conditions. Acupuncture is generally used only in combination with other forms of treatment. The global ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acupressure
Acupressure is an alternative medicine technique often used in conjunction with acupuncture or reflexology. It is based on the concept of life energy, which flows through "meridians" in the body. In treatment, physical pressure is applied to acupuncture points, or ashi trigger points, with the aim of clearing blockages in these meridians. Pressure may be applied by hand, by elbow, or with various devices. Although some medical studies have suggested that acupressure may be effective at helping manage nausea and vomiting, insomnia, low back pain, migraines, and constipation, among other things, such studies have been found to have a high likelihood of bias. There is no reliable evidence for the effectiveness of acupressure. Background Acupressure therapy was prevalent in India. After the spread of Buddhism to China, the acupressure therapy was also integrated into common medical practice in China and it came to be known as acupuncture. Scholars note these similarities becau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Anaesthetic
General anaesthetics (or anesthetics, see spelling differences) are often defined as compounds that induce a loss of consciousness in humans or loss of righting reflex in animals. Clinical definitions are also extended to include an induced coma that causes lack of awareness to painful stimuli, sufficient to facilitate surgical applications in clinical and veterinary practice. General anaesthetics do not act as analgesics and should also not be confused with sedatives. General anaesthetics are a structurally diverse group of compounds whose mechanisms encompasses multiple biological targets involved in the control of neuronal pathways. The precise workings are the subject of some debate and ongoing research. General anesthetics elicit a state of general anesthesia. It remains somewhat controversial regarding how this state should be defined. General anesthetics, however, typically elicit several key reversible effects: immobility, analgesia, amnesia, unconsciousness, and reduce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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