Many nurses have a poor understanding of pain and its management, which can result in failure to treat pain effectively. An insight into the anatomy and physiology of pain is essential to increase nurses’ understanding of. Human anatomy and physiology by Marieb 8th test bank chapter 3 1. Choose the one alternative that best completes the statement or answers. Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight. Birds have a light skeletal system and light but powerful musculature which, along with circulatory and. Introduction and Background, Anatomy and Physiology, Etiology of Smell and Taste Disorders. Olfactory dysfunction. Disturbances in olfaction can result from pathologic processes at any level along the olfactory pathway. They can be classified in a way analogous to otologic dysfunction, as conductive or sensorineural defects. In conductive (ie, transport) defects, transmission of an odorant stimulus to the olfactory neuroepithelium is disrupted. Sensorineural defects involve the more central neural structures. Overall, the most common causes of primary olfactory deficits are aging, nasal and/or sinus disease, prior viral upper respiratory tract infections (URTIs), and head trauma. These may include rhinitis of various types, including allergic, acute, or toxic (eg, cocaine use). Chronic rhinosinusitis causes progressive mucosal disease and often leads to decreased olfactory function despite aggressive allergic, medical, and surgical intervention. Masses may block the nasal cavity, preventing the flow of odorants to the olfactory epithelium. These include nasal polyps (most common), inverting papilloma, or any nasal tumor. Developmental abnormalities (eg, encephaloceles, dermoid cysts) also may cause obstruction. Patients with laryngectomies or tracheotomies experience hyposmia because of a reduced or absent nasal airflow. There are several impressions on the surface of the liver which accommodate the various adjacent structures and organs. Underneath the right lobe and to the right of the gallbladder fossa, are two impressions, one behind the. Corneal physiology OPTO : Ihsan Hmaid 2. Cornea :Cornea characteristics 1. Forms the anterior 1/6 of the outer tunic. Completely transparent. Historically, disorders of taste and smell have been difficult to diagnose and treat, often because of a lack of knowledge and understanding of these senses and their disease states. Children with tracheotomies who are cannulated very young and for a long period may have a continued problem with olfaction even after decannulation because of a lack of early stimulation of the olfactory system. Central/sensorineural defects. Infectious and inflammatory processes contribute to central defects in olfaction and in transmission. These include viral infections (which may damage the neuroepithelium), sarcoidosis (affecting neural structures), Wegener granulomatosis, and multiple sclerosis. Once thought to be mostly a conductive defect through mucosal edema and polyp formation, chronic rhinosinusitis also appears to disrupt the neuroepithelium with irreversible loss of olfactory receptors through up- regulated apoptosis. Head trauma, brain surgery, or subarachnoid hemorrhage may stretch, damage, or transect the delicate fila olfactoria or damage brain parenchyma and result in anosmia. In one study the average loss in human mitral cells was 5. Kallmann syndrome is one type of congenital smell loss and is due to failed olfactory structure ontogenesis and hypogonadotropic hypogonadism. One study found the vomeronasal organ to be absent in patients with Kallmann syndrome. Endocrine disturbances (eg, hypothyroidism, hypoadrenalism, diabetes mellitus) may affect olfactory function. Toxicity of systemic or inhaled drugs (eg, aminoglycosides, formaldehyde) can contribute to olfactory dysfunction. Many other medications and compounds may alter smell sensitivity, including alcohol, nicotine, organic solvents, and direct application of zinc salts. On June 1. 6, 2. 00. US Food and Drug Administration (FDA) issued a public health advisory and notified consumers and healthcare providers to discontinue use of intranasal zinc products. The intranasal zinc products (Zicam Nasal Gel/Nasal Swab products by Matrixx Initiatives) are herbal cold remedies that claim to reduce the duration and severity of cold symptoms and are sold without a prescription. The FDA received more than 1. Many of the reports described the loss of smell with the first dose. That withstanding, research has identified squamous metaplasia and change in the morphology of the olfactory receptor neurons and a higher level of apoptosis of these neurons in smokers compared with controls. In addition, there is evidence that the volume of the olfactory bulb is reduced in smokers. It has been shown that patients with acute major depressive disorder have reduced olfactory sensitivity and reduced olfactory bulb volumes. Alzheimer and Parkinson patients show changes in detection, discrimination, and identification of odors compared with age- matched controls. The severity of dysfunction is correlated to disease progression. In most cases, olfactory loss is present years before motor or cognitive symptoms. However, this is usually a gradual loss and often goes unnoticed or unreported by patients. A study by Cecchini et al found severe olfactory impairment in persons with Down syndrome, with these individuals performing worse than euploid controls on tests of odor detection threshold, odor discrimination, and odor identification. Among 5. 6 subjects with Down syndrome, 2. There are numerous functional and structural approaches available to assess the olfactory system, including psychosocial and electrophysiological testing, as well as imaging studies. Objective measures of olfactory function may serve as an early marker for these diseases or as a prognostic indicator. An understanding of the mechanism of the decrease in smell could help to further elucidate the pathophysiology of these disorders or uncover new treatments. The components that comprise the sensation of flavor include the food's smell, taste, texture, and temperature. Each of these sensory modalities is stimulated independently to produce a distinct flavor when food enters the mouth. Taste may be enhanced by tongue movements, which increase the distribution of the substance over a greater number of taste buds. Adaptation in taste perception exerts a greater influence than in other sensory modalities. Other than smell dysfunction, the most frequent causes of taste dysfunction are prior URTI, head injury, and idiopathic causes, but many other causes can be responsible. Lesions at any site from the mucosa, taste buds, unmyelinated nerves, or cranial nerves to the brain stem may impair gustation. Oral cavity and mucosal disorders including oral infections, inflammation, and radiation- induced mucositis can impair taste sensation. The site of injury with radiotherapy is probably the microvilli of the taste buds, not the taste buds themselves, since taste buds are thought to be radioresistant. Poor oral hygiene is a leading cause of hypogeusia and cacogeusia. Viral, bacterial, fungal, and parasitic infections may lead to taste disturbances because of secondary taste bud involvement. Normal aging produces taste loss due to changes in taste cell membranes involving altered function of ion channels and receptors rather than taste bud loss. Resection of the tongue and/or portions of the oral cavity, most commonly for reasons of malignancy, decreases the number of taste buds. Radiation and chemotherapy damage taste receptors and decrease salivary flow, altering taste perception. In otologic surgery, stretching or transection of the chorda tympani nerve may result in temporary dysgeusia. Bilateral injury still may not result in permanent taste dysfunction, because of the alternate innervation through the otic ganglion to the geniculate ganglion via the greater superficial petrosal nerve. Gastric bypass surgery can also have adverse olfactory and gustatory effects. In a study by Graham et al of 1. Roux- en- Y gastric bypass, sensory changes in taste and smell were reported by 7. Decreased zinc, copper, and nickel levels can correlate with taste alterations. Nutritional deficiencies may be caused by anorexia, malabsorption, and/or increased urinary losses. Endocrine disorders also are involved in taste and olfactory disorders. Diabetes mellitus, hypogonadism, Sjogren. Hormonal fluctuations in menstruation and pregnancy also influence taste. AIDS patients often complain of alterations in taste, and detection thresholds of glutamic acid and hydrochloride are higher in patients suffering from AIDS. The ability to taste phenylthiourea (bitter) and other compounds with an . Studies have shown that phenylthiourea tasters detect saccharin, potassium chloride (KCl), and caffeine as more bitter. Type I familial dysautonomia (ie, Riley- Day syndrome) causes severe hypogeusia or ageusia because of the absence of taste bud development. Direct nerve or CNS damage, as in multiple sclerosis, facial paralysis, and thalamic or uncal lesions, can decrease taste perception. Many other diseases can affect gustation (eg, lichen planus, aglycogeusia, Sj.
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January 2017
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