By I. Carlos. Eastern Michigan University. 2018.
Optic tract Md Optic radiation Optic chiasm Optic nerve (CN II) Temporal loop of optic radiation (Meyer’s loop) Lateral ventricle (inferior horn) Md = Midbrain FIGURE 41A: Visual System 1 — Visual Pathway 1 © 2006 by Taylor & Francis Group order 100mg aurogra otc erectile dysfunction song, LLC 110 Atlas of Functional Neutoanatomy reﬂex (reviewed with the next illustration) purchase aurogra 100 mg visa impotence specialists. Some other FIGURE 41B ﬁbers terminate in the suprachiasmatic nucleus of the VISION 2 hypothalamus (located above the optic chiasm), which is involved in the control of diurnal (day-night) rhythms. The additional structures labeled in this illustration VISUAL PATHWAY 2 AND VISUAL CORTEX have been noted previously (see Figure 17 in Section A), (PHOTOGRAPHS) except the superior medullary velum, located in the upper part of the roof of the fourth ventricle (see Figure 10); this We humans are visual creatures. We depend on vision for band of white matter is associated with the superior cer- access to information (the written word), the world of ebellar peduncles (discussed with the cerebellum, see Fig- images (e. There are many cortical areas devoted to interpreting the visual world. CLINICAL ASPECT UPPER ILLUSTRATION (PHOTOGRAPHIC VIEW) It is very important for the learner to know the visual system. The system traverses the whole brain and cranial The visual ﬁbers in the optic radiation terminate in fossa, from front to back, and testing the complete visual area 17, the primary visual area, speciﬁcally the upper pathway from retina to cortex is an opportunity to sample and lower gyri along the calcarine ﬁssure. The posterior the intactness of the brain from frontal pole to occipital portion of area 17, extending to the occipital pole, is where pole. The adjacent cortical areas, areas 18 and 19, are Visual loss can occur for many reasons, one of which visual association areas; ﬁbers are relayed here via the is the loss of blood supply to the cortical areas. The visual pulvinar of the thalamus (see below and Figure 12 and cortex is supplied by the posterior cerebral artery (from Figure 63). There are many other cortical areas for elab- the vertebro-basilar system, discussed with Figure 61). In some cases, macular sparing is found after This is a higher magniﬁcation of the medial aspect of occlusion of the posterior cerebral artery, presumably the brain (shown in Figure 17). The interthalamic adhe- because the blood supply to this area was coming from sion, ﬁbers joining the thalamus of each side across the the carotid vascular supply. The optic chiasm is seen anteriorly; posteriorly, the tip of the pulv- ADDITIONAL DETAIL inar can be seen. The midbrain includes areas where ﬁbers The work on visual processing and its development has of the visual system synapse. It is now thought and 19, the visual association areas of the cortex (shown that the primate brain has more than a dozen specialized in the previous diagram, alongside area 17). Some optic visual association areas, including face recognition, color, ﬁbers terminate in the superior colliculi (see also Figure and others. Neuroscience texts should be consulted for 9A and Figure 10), which are involved with coordinating further details concerning the processing of visual infor- eye movements (discussed with the next illustration). Visual ﬁbers also end in the pretectal “nucleus,” an area in front of the superior colliculus, for the pupillary light © 2006 by Taylor & Francis Group, LLC Functional Systems 111 P Parieto-occipital ﬁssure F O Visual association cortex (areas 18 & 19) T Md Calcarine ﬁssure Primary visual cortex (area 17) T Po M SC Cingulate gyrus Corpus callosum Roof of Lateral 3rd ventricle ventricle Septum Posterior pellucidum (cut) commissure Fornix Splenium of corpus Foramen T callosum of Monro Pulvinar Anterior commissure Superior Md and inferior Interthalamic colliculi adhesion Aqueduct of Optic chiasm midbrain T Superior Mammillary Po medullary body velum 4th ventricle F = Frontal lobe T = Talamus M = Medulla P = Parietal lobe Md = Midbrain SC = Spinal cord T = Temporal lobe Po = Pons O = Occipital lobe FIGURE 41B: Visual System 2 — Visual Pathway 2 and Visual Cortex (photograph) © 2006 by Taylor & Francis Group, LLC 112 Atlas of Functional Neutoanatomy FIGURE 41C of the colliculi (the other name for the colliculi is the tectal area, see Figure 9A, Figure 10, and VISION 3 Figure 65), called the pretectal area (see also Figure 51B), is the site of synapse for the pupil- lary light reﬂex. Shining light on the retina VISUAL REFLEXES causes a constriction of the pupil on the same The upper illustration shows the details of the optic radi- side; this is the direct pupillary light reﬂex. Fibers also cross to the nucleus on the other The ﬁbers end in the visual cortex along both banks of side (via a commissure), and the pupil of the the calcarine ﬁssure, the primary visual area, area 17 (see other eye reacts as well; this is the consensual Figure 41A and Figure 41B). The efferent part of the reﬂex This illustration also shows some ﬁbers from the optic involves the parasympathetic nucleus (Edinger- tract that project to the superior colliculus by-passing the Westphal) of the oculomotor nucleus (see Fig- lateral geniculate via the brachium of the superior colli- ure 8A and also Figure 65A); the efferent ﬁbers culus (labeled in the lower illustration). This nucleus course in CN III, synapsing in the ciliary gan- serves as an important center for visual reﬂex behavior, glion (parasympathetic) in the orbit before particularly involving eye movements. Fibers project to innervating the smooth muscle of the iris, which nuclei of the extra-ocular muscles (see Figure 8A and controls the diameter of the pupil. Figure 51A) and neck muscles via a small pathway, the tecto-spinal tract, which is found incorporated with the CLINICAL ASPECT MLF, the medial longitudinal fasciculus (see Figure 51B). The pupillary light reﬂex is a critically important clinical Reﬂex adjustments of the visual system are also sign, particularly in patients who are in a coma, or fol- required for seeing nearby objects, known as the accom- lowing a head injury. It is essential to ascertain the status modation reﬂex. A small but extremely important group of the reaction of the pupil to light, ipsilaterally and on of ﬁbers from the optic tract (not shown) project to the the opposite side. The learner is encouraged to draw out pretectal area for the pupillary light reﬂex. Three events occur simul- of the retina, there can be a reduced sensory input via the taneously — convergence of both eyes (involv- optic nerve, and this can cause a condition called a “rel- ing both medial recti muscles), a change ative afferent pupillary defect. Both pupils will constrict when the light is shone visual information to be processed at the corti- on the normal side. The descending cortico-bulbar ﬁbers eye, because of the diminished afferent input from the (see Figure 46 and Figure 48) go to the oculo- retina to the pretectal nucleus, the pupil of this eye will motor nucleus and inﬂuence both the motor dilate in a paradoxical manner. This results in a ﬁxed dilated pupil, via the ciliary ganglion) to effect the pupil on one side, a critical sign when one is concerned reﬂex.
This allows the body to absorb the natural forces flowing about us constantly like a sponge trusted 100mg aurogra erectile dysfunction pills wiki, and enables one to swiftly circulate the added vitality throughout the body discount aurogra 100mg with mastercard erectile dysfunction pills cost. With all these routes open, every organ re- ceives its full complement of energy and remains in harmony with the rest of the body system. The warm current of “chi” helps wash away any blockage that might be present, massages the internal organs, and restores health to damaged and abused tissues. Many deadly diseases are prevented and the effects of stress and nervous tension are effec- tively flushed out of the system. Many practitioners open all the - 28 - Chapter I routes within a few months and learn to reduce leakage of their bodily energy to the point where an EEG records little or no energy waves. Acupuncture and Microcosmic Orbit The Chinese sages studied the flow of energy from these two main channels, the Functional and Governor that connect to form the microcosmic orbit, and discovered other energy flow routes. It was along these energy meridians that the points used in acupuncture healing were also discovered. But before the art of acupuncture developed, using needles to impede or enhance energy flow along the various routes in an effort to restore normal function, the Chi- nese healers relied on circulating their energy internally in the ba- sic microcosmic orbit to insure good health, love and long life. These masters of long life were much sought after, even besieged to teach the secret of living a long and harmonious life. When acupuncture was first introduced it was considered an inferior form of medicine and was used mostly in extreme cases of sickness. The best doctors in China were the doctors who kept their patients from getting sick in the first place. Today, while we are beginning to ac- cept acupuncture as a reliable medical practice, we have yet to recognize our innate ability to prevent illness and heal ourselves using the energy flowing naturally through our bodies. Summary In the Taoist system one begins by opening and completing two main channels, up the spine in back and down the front of the body. When linked together by the tongue on the roof of the mouth, these two routes form the Microcosmic Orbit and serve as a circu- latory system for the body with built-in cooling safety valves. Human energy tends to flow upward during meditation and may cause immense heat to accumulate in the brain coupled with bodily sensation, visual and auditory hallucinations, emotional outbursts, and various delusions. By completing up to a total of thirty-two routes (these smaller routes are not covered in this volume) the energy is well circulated, greatly reducing the overheating side effects of concentrated meditation and inducing relaxation. Many formulas are needed to bring about the proper effects and to harmonize the various energy systems of the body with the energy system of nature. As more power becomes avail- able, the importance of opening the various routes becomes evi- dent. Without many clear and commodious channels to transport a considerable increase in energy, damage can result from an over- load. These side effects range from the physical to the psychologi- cal and can be quite disturbing, even debilitating. If any side effects should ever occur, see the chapter on Safety Precautions and if necessary ask for advice immediately from a teacher of Taoist yoga. If you proceed one step at a time up the ladder, you will be guaranteed success in reaching the top. If you are dis- tracted by the television, passing cars, or your unmade bed, your mind will turn outwards and you will be unable to focus on your energy. As you progress you will learn to ignore the distractions and will be able to meditate anywhere, but in the beginning choose a quiet spot and a special time. The more comfortable the atmo- sphere the more easily you can concentrate. Clothes During Chi (meditation) dress in loose-fitting clothing. Remember to keep the knees, nape of the neck and toes free of binding clothing. Dress warmly enough so that you are not distracted by the cold. Room The room must be kept well-ventilated, but do not sit in front of a window. The body generates excess heat during meditation and a draft may cause a cold. If a room is too light it will disturb your concentration; if too dark it may make you sleepy. Diet According to the Taoist masters, if you stop eating when you are two-thirds full your stomach will have room to digest the food. When you are too full you lose lucidity and power of concentration.
The name therefore suggests that AS is an inﬂammatory disease of the spine that can lead to stiffening of the back cheap 100 mg aurogra free shipping erectile dysfunction under 40. It is sometimes called just spondylitis for short aurogra 100 mg fast delivery erectile dysfunction doctors charlotte, but this word should not be confused with spondylosis, which relates to wear and tear in the spinal column as we get older. The most commonly involved sites are the sacroiliac joints and the spine. Other, relatively less commonly involved sites are hip and shoulder joints, and less often the knee joints. AS in history and literature AS has affected people since ancient times. One such sufferer was the famous Egyptian Pharaoh Ramses II. The ﬁrst deﬁnite description of AS can be credited to an Irish physician, Bernard Conner (1666–1698). When he was studying medicine in France, some farmers brought him a skeleton they had found in a cemetery. He wrote that the bones were ‘so straightly and intimately joined, their liga- ments perfectly bony, and their articulations so effaced, that they really made but one uniform con- tinuous bone’ (Figure 2). The ﬁrst clinical descriptions of the disease date from the late nineteenth century, and the medical interest in AS was stimulated by a series of publica- tions in the 1890s by Vladimir von Bechterew (1857–1927) in St Petersburg, Russia. Other clinical reports on AS were published by Adolf Strümpell (1853–1926) and Pierre Marie (1853–1940). Valentini published the earliest X-ray examination of a patient with AS in 1899, and in 1934 Krebs described the characteristic obliteration of the sacroiliac joints. Although AS is a readily observed disorder in people with advanced disease, it has rarely appeared in literature. Eudora Welty mentioned it in a short story ‘The Petriﬁed Man’, published in the Southern Review of 1938–1939. Terminology Over the years AS has been known by many dif- ferent names, including: • spondylitis ankylosans thefacts 7 AS-02(5-12) 5/29/02 5:41 PM Page 8 Ankylosing spondylitis: the facts Figure 2 First representation of a skeleton with AS in its ﬁnal state by Bernard Conner, London, 1695. During the ﬁrst half of the twentieth century AS was wrongly called ‘rheumatoid spondylitis’, partic- ularly in the USA, because of the mistaken belief that it was just a variant of rheumatoid arthritis. Structure of the spine The spine consists of 24 vertebrae that are stacked one above the other and held together by strong ligaments and by more than 100 joints (Figure 3). It is divided into three main sections: • the upper part, in the neck (cervical spine) has 7 vertebrae • the middle part (thoracic spine) has 12 vertebrae • the lower part (lumbar spine) has 5 vertebrae. Atlas Atlas Axis Axis Cervical Cervical vertebrae vertebrae Thoracic Thoracic vertebrae vertebrae Lumbar Lumbar vertebrae vertebrae Sacrum Sacrum Coccyx Coccyx Figure 3 The vertebral column. The 12 ribs on either side that make up the chest wall are attached to the thoracic vertebrae in the back by joints called costovertebral and costo- transverse joints, and are attached to the breastbone (sternum) in the front chest wall by costochondral junctions. This bone is called the sacrum, and it looks like a keystone in the circular pelvis. It is attached on either side to the pelvic bone called the ilium by joints called sacroiliac joints, and by strong liga- ments (Figure 4). The front part of the pelvic bone (not shown in Figure 4) is called the pubis, and the pubic bones of the two sides form a junction in the middle called the pubic junction (or pubic sym- physis). The lower part of the pelvic bone that bears our weight when we are sitting down is called the gluteal tuberosity; there is one on either side, cush- ioned by the buttock. Family history AS does tend to run in families, and studies indi- cate that there is a genetic predisposition to it. This was clearly established in 1973, when researchers found a remarkable association of AS with a genetic marker called HLA-B27, which is discussed in more detail later in the book (Chapter 16). HLA-B27 is 10 thefacts AS-02(5-12) 5/29/02 5:42 PM Page 11 What is ankylosing spondylitis? The prevalence of this gene is very different in other racial groups, as also discussed in Chapter 16. Current research is focusing on identiﬁcation of the additional genes that pre- dispose people to AS, and the activating agent or infection that triggers the disease. Developments in treatment The ﬁrst major advance in drug therapy in AS came with the availability of the ﬁrst non-aspirin non-steroidal anti-inﬂammatory drugs (NSAIDs), especially phenylbutazone, in the mid-twentieth century. Many other NSAIDs have since been discovered that are safer than phenylbutazone, but none of them is more effective in relieving the pain and inﬂammation of AS. The latest potential break- through is the remarkable efﬁcacy of anti-TNF therapy in AS patients who do not respond ade- quately to NSAIDs and other conventional medica- tion (see Chapter 6). The pain caused by sacroiliitis is usually a dull ache that is diffuse, rather than localized, and is felt deep in the buttock area. At ﬁrst it may be intermittent or on one side only, or alternate between sides; however, within a few months it generally becomes persistent (chronic) and is felt on both sides (bilateral). Gradually the lower back becomes stiff and painful, as the inﬂammation extends to the spine in that area (lumbar spine). Over many months or years the back pain can gradually extend further up the spine to the area between the shoulder blades or even to the neck. These initial symptoms usually start in late adolescence or early adulthood.
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