By P. Milok. Brown University. 2019.
If the hospital house keeping is of poor quality purchase 160mg malegra fxt plus with mastercard, nursing care suffers cheap malegra fxt plus 160 mg without prescription, nursing education is adversely affected cheap malegra fxt plus 160mg with mastercard, efficiency is lowered and the morale is impaired purchase malegra fxt plus 160mg visa. Purpose in cleaning: 1) To leave a clean polished surface where possible, so that dirt may not be accumulated. Natural and synthetic rubber deteriorate with age, exposure to heat, light, moistures and by chemi cals. Cleaning of rubber mackintosh: 1) Spread the mackintosh on the table or a flat surface and wet with cold water 2) Rub the upper surface with soap and water 3) Turn the other side rub with soap and water 4) If strains are present to be removed. Care of Rubber Gloves: 1) It is desired that the wearer of the gloves should wash on their hands just before they are removed. Cleaning of rubber tubes: 1) After use, wash them under running water 2) A small quantity of organic matter may be lodged at the eye end. Remove them using a swap stick 3) Clean them with the soap and water 170 4) Wash them again under running water 5) Boiled tubes for 5 minutes by putting them in the boiled water. It should be cleansed and disin fected by using Lysol solution 1:40 Care of the kidney trays: 1) Before emptying the kidney tray, inspect the contents. Sharp instruments are sterilized by hot air sterilizer exposing into a temperature of 160 c for an hour. Care of glassware: Cleaning of the glass ware should have a hard smooth surface ground glass susceptible to erosion by water or steam. When the glass goods are sent for autoclaving or boiling, should be adequately padded to prevent braking by rubbing with hard surfaces. Care of syringes and needles: Syringes are expensive and common item of the glass ware used in the hospital. Rinsing immediately after use to prevent the pistons sticking to the barrels, thus prolonging the life of syringes. The important points to remember 1) After use cold water is forced through the needle with the syringes 2) Again wash it with warm water 3) If the needles are blocked wire stillest are used to remove 4) Needles are sterilized by 10 – 20 minutes. Care of the stainless good: Stainless steel utensils are suitable for almost every other purpose because they are easily cleaned, heat resistant and unbreakable. General instructions for removal of strains from the linens: 1) Try whether the strains can be removed with cold water. For the thick blood stains on the mattress, apply a thick paste of starch and water and allow to stand in the sun. Tea coffee, coco: Linen when it is stained with tea, coffee, and coco, remove it by pouring milk over it. Rust marks: Apply salt and lime juice and exposed to sun light Ink strain: Sprinkle salt and lime juice and lay in the sun to bleach the strain Care of blankets: These are expensive articles and do not stand washing or steam disinfections without shrinkage. Care of mattress and pillows: Mattress should be brushed at regular and frequent intervals to prevent collection of dust and along the seams. To prevent rusting of the mattress from the wires or springs, use canvass between the mattress and bed sheett. They should be protected with mackintoshes when they are used for the patients with bleeding, vomiting etc. Care of the sanitary annex: Sanitary annex attached to the wards consist of bathing rooms, lavatories, hand washing places, place for washing and storing of bed pans, urinals etc. No water should stagnate in the bathing room Lavatories: Lavatories pans should be cleaned with vim or sane fresh, using a brush if strains are present, smear a small amount of acid and wash it off. Hand washing place: The drains may become blocked by the refuse thrown into the sinks by the patients. Elizabeth College of Nursing Government Higher Secondary School Chengalpet Medical College Ottanchantram. Special recognition and due acknowledge is hereby made to the Director of School Education and the Joint Director of School Education Chennai. The nurse has multifaceted role in hospital settings as a care provide to clients, administrator, superviosor, etc. This book is written for the higher secondary students who need to gain the practical before joining the professional course in Nursing. Guidelines 1) Work systematically 2) Plan the work 3) Collect equipment in the order that they are to be used. The mucous membrane is an epithelial tissue that lines and protects organs, secretes mucous to keep pas sageways of digestive system moist and lubricated, and absorbs nutrition. Purposes of Mouth Care 1) Oral Hygiene helps maintain the healthy state of the mouth, teeth, gums and lips. Proper Mouth Care 1) Good oral hygiene involves cleanliness, comfort and the moisturizing the mouth structures. Common Oral problems: The two major types of Oral problems are dental caries (cavities) and periodontal disease (Pyorrhoea) Dental caries is the most common oral problem of younger people. Decalcification is a result of an accumulation of mucin, carbohydrates and lactic acid bacilli in the saliva normally found in the mouth, which forms a coating on the teeth called plaque. Causes: (1) Riboflavin deficiency (2) Mouth breathing (3) Excess salivation Stomatitis is an inflammative condition of the mouth Causes: (1) Vitamin deficiency (2) Infection by bacteria, viruses or fungi (3) Use of Chemotherapeutic drugs Glossitis is an inflammation of the tongue resulting from an infectious disease or injury such as burn or bite. Causes: (1) Pipe smoking (2) Tobacco Chewing Equipments A tray containing 1) Cotton swab or clean pieces in a bowl 2) Forceps (artery and dissecting forceps) 3) Gallicups 2 nos. If the patient is unable to do so, the nurse has to remove the dentures by grasping it with gauze pieces, place them in a tumbler or cup containing water. But when an individual is confined to bed, the weight of his body has to be borne by his back or sides. The skin of the soles of our feet is very tough and thick and it does not break easily in spite of the entire weight of the body being supported by it. The nature has designed the sole of the skin for weight bearing whereas the skin over the back of the body is not. When there is pressure on the skin of the back because of the weight of the body, the skin breaks and an ulcer develops. Definition of Decubitus Ulcer: A decubitus ulcer is a pressure sore resulting from prolonged confinement in bed. These various pictures are illustrating different body positions and the pressure areas Elbows Scapulae Back of head Heels Sacrum (Olecranon Process) (Occipital bone) (Calcaneus) Malleolus Knee Ear Llium (medial (medial Shoulder Side of head and and lateral Greater (acromial (parietal and lateral) condyles) trochanter process) temporal bones) C. Prone Position Toes Knees Genitalia Breasts Shoulder Cheek and ear (phalanges) (patellas) (men) (women) (acromial (zygomatic process) bone) 7 D. Heels (calcaneus) Vertebrae (spinal processes) 30 ° Pelvis Sacrum (ischial tuberosity) Causes of Decubitus Ulcer: Local causes: (a) Pressure: When any body prominence presses upon the bed, the tissues lying between them get reduced blood supply. If this condition prolongs, the superficial tissues necroses, skin breaks down and formation of an ulcer takes place. The following condition causes prolonged pressure: 1) Leaving a patient in one position for a long time. These patients are unable to appreciate the weight of pressure and change their position 2) Paralysed patients (Paraplegic and quadriplegic patients). Diabetes Prevention of decubitus ulcers: A) Prevent Pressure: 1) Establish a turning schedule for bedridden patients; turn hourly. B ) Prevent Friction: 1) When changing position of your patient lift him and do not drag him on to bed. D ) Prevent Predisposing causes: 1) Improve patient’s health by means of good food, ventilation, sunlight and exercises. E ) Observe early signs and symptoms of decubitus ulcers: 1) Redness 2) Dark discoloration 3) Bruising 4) Tenderness of the area 5) Burning sensation 9 F ) Give good care to pressure points: Careful cleaning and massage should be carried out 3 or 4 times a day for all bedridden patients. Equipment 1) A bowl of warm water 2) Sponge cloth 3) Soap 4) Towel 5) Dusting powder 6) Spirit Procedure: 1) Explain procedure to patient Arrange articles at the bedside. Treatment of decubitus ulcer: 1) Clean ulcers with aseptic precautionsUse antiseptics such as eusole (or) hydrogen peroxide. Give long firm strokes from back of neck to the buttocks 14) Watch for any redness over the pressure areas. Type of Therapeutic Baths 1) Hot water tub bath: Immersion in hot water helps relieve muscle soreness and spasm. Problems may result from poor care of the feet and nails such as biting nails or trimming them improperly, exposure to chemicals and wearing poorly fitted shoes.
However trusted 160mg malegra fxt plus, we recently found that suicide are the principal risk factors quality 160mg malegra fxt plus, and there were no cases urgent thoracotomy is mandatory in salvaging unstable with commotio cordis or gunshot wounds buy malegra fxt plus 160mg visa. Lund / Interactive Cardiovascular and Thoracic Surgery 2 (2003) 53–57 all to maintain an optimal blood pressure (not too high and rupture: twenty-year metaanalysis of mortality and risk of paraplegia buy generic malegra fxt plus 160 mg on-line. Cardiac injuries: a ten-year publication of the ﬁrst report describing the initial experi- experience. In our Lachat M, Pfammatter T, Witzke H, Bernard E, Wolfensberger U, study, direct suture was performed only in one patient and Kunzli A, Turina M. Such a Message: Injury to the heart and great vessels is not limited to countries beneﬁcial effect was clearly seen in our series where para- with interpersonal violence. In the future, increasing delay in operative therapy will be applied to “stable” patients with thoracic aortic injury and there will be increasing utility for intravascular stented grafts. Review of 1198 cases of penetrating cardiac injury to the catheterization laboratory equipped with endovascular trauma. I disagree with their diagnostic Author: Professor Angelo Pierangeli, University of Bologna, Cardio- approach. Moreover, the angiography can increase the risks of fatal Message: In the present paper the authors describe their experience in complications. Produced in collaboration with the Ethiopia Public Health Training Initiative, The Carter Center, the Ethiopia Ministry of Health, and the Ethiopia Ministry of Education. Important Guidelines for Printing and Photocopying Limited permission is granted free of charge to print or photocopy all pages of this publication for educational, not-for-profit use by health care workers, students or faculty. Under no circumstances is it permissible to sell or distribute on a commercial basis, or to claim authorship of, copies of material reproduced from this publication. Except as expressly provided above, no part of this publication may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording, or by any information storage and retrieval system, without written permission of the author or authors. This material is intended for educational use only by practicing health care workers or students and faculty in a health care field. I believe that transfer of scientific knowledge in oral health could be beneficiary to the needy population where oral health is found in a low standard. In our country there is no enough qualified human resource in dental profession, however the need for dental service is increasing. Teaching oral health care to health officer students even to other health science students will definitely will help the people get better service in the area. Majority of the Ethiopian population has no proper dental service; they are getting help by the local practitioners. Even though not to be appreciated, it is undeniable that the local practitioners, had contributed and are contributing a lot to the people, in areas where there is no dental service. Mal practice, lack of knowledge and un sterile instruments had resulted in bad outcomes like fracture of the mandible, dislocation of the temperomandibular joint, Fracture of tooth and roots etc. Even though it is not within the scope of this material to cover all dental related problems, I have tried to include the common dental problem, their management and prevention precisely. I would like to acknowledge Dr Mesfin Addise for the information, supports and useful suggestions which were useful for the preparation. I would like to acknowledge W/t Seblewongel Nigussie, the secretary of the general manager of the Association. My special acknowledgement goes to the Authors of Texts, Journals, and Articles which I referred and used their work. Finally my incredible acknowledgement goes to all my friends, family members, and especially to my daughters, Eden Bekele, Mariam Bekele, Ruth Bekele, Tigist Alemayehu, and Fikiraddis Abate. In the past all Africans were assumed to have good teeth, therefore the need for oral health was not given priority. At present there are about 55 dentists including specialists in some of the special fields of dentistry. At present the center is upgraded to a dental school and training students in bachelor of dental 1 science, Jimma University has recently started training Doctor of Dental Medicine. Preliminary studies done in the past showed that the Ethiopians have good teeth with low rate of caries prevalence; however caries is on the increase because of the replacement of none carious foods of developing countries by sugar rich western foods. Even though in recent years in Ethiopia research works are not done, however, the need for dental service is growing, the resource are scarce and maldistributed, skilled human resource in the country is very few. I hope this type of training in oral health care will contribute in prevention of infections which may be transmitted through mal practices by untrained practitioners. This had influenced peoples’ mind and caused differences in many conditions not 2 excluding medical field. In the field of dentistry, differences in medical terminologies like Dentistry or stomatology, Oral surgery or surgical stomatology were the results of those times. In Boucher’s Dictionary of Clinical Dental Terminology, the defination of terminologies is given as follows: Stomatology is the study of the morphology, structure, function and diseases of the contents and lining of the oral cavity. Dentistry is the science and art of preventing, diagnosing, and treating, diseases, injuries and malformations of the teeth, jaws and mouth and of replacing lost or absent teeth and associated structures. Pediatric Dentistry/pedodontics - conservative Pediatric Dentistry - Surgical Pediatric Dentistry - Othodontics Pediatric Dentistry b. Dental and maxillofacial radiology Course Objective After the completion of the course the student will be able to: • Identify and treat common oral and dental diseases • Plan, promote and organize preventive oral health Course content 1. Figure 1: Anatomy of the oral cavity 7 Anatomy of the teeth Tooth is made up of enamel, dentine, pulp and cement. Dentin This sensitive ivory like substance that forms the body of the whole teeth Pulp This is an extremely sensitive mass of thin nerve and blood vessels which enter through apical canal at the apex of each root. Figure 2: Dental anatomy Root Premolar Neck Crown 9 Table 1: Chemical composition of tooth Enamel Dentine Pulp Inorganic subst. According to their development- Deciduous and permanent According to their function -- Incisors, Canines, premolars and molars. Premolars and Molars: Grinding the food in to small pieces before swallowing Arterial Supply to the Teeth and oral cavity The arteries and nerve branches to the teeth are mere terminals of the central systems. This manual will only confine to dental anatomy and the parts immediately associated structures, therefore reference be made only to those branches that supply the teeth and the supporting structures. Internal Maxillary Artery The arterial supply to the jaw bones and the teeth comes from the maxillary artery, which is a branch of the external carotid artery. The branches of the maxillary 12 artery which feed the teeth directly are the inferior alveolar artery and the superior alveolar arteries. Inferior Alveolar Artery The inferior alveolar artery branches from the maxillary artery medial to the ramus of the mandible. It gives off the mylohyoid branch, it supplies: ¾ the premolar and molar teeth ¾ the chin ¾ the anterior teeth ¾ the mandible and teeth. Supperior Alveolar Arteries The posterior superior alveolar artery branches from the maxillary artery superior to the maxillary tuberosity to enter the alveolar canals along with the posterior superior alveolar nerves and supplies: ¾ the maxillary teeth, ¾ Alveolar bone and membrane of the sinus. A middle superior alveolar branch is usually given off by the infraorbital continuation of the maxillary artery. It supplies ¾ the maxillary anterior teeth and their supporting tissues Branches to the teeth, periodontal ligament, and bone are derived from the superior alveolar 14 Figure 3: Branches of maxillary artery 15 Nerve Supply The sensory nerve supply to the jaws and teeth is derived from the maxillary and mandibular branches of the fifth cranial, or trigeminal, nerve, whose ganglion, the trigeminal, is located at the apex of the petrous portion of the temporal bone. Maxillary Nerve The maxillary nerve crosses forward through the wall of the cavernous sinus and leaves the skull through the foramen rotundum. The branches of clinical significance include: ¾ a greater palatine branch that enters the hard palate through the greater palatine foramen and 16 is distributed to the hard palate and palatal gingivae as far forward as the canine tooth; ¾ a lesser palatine branch from the ganglion that enters the soft palate through the lesser palatine foramina; and ¾ a nasopaaltine branch of the posterior or superior lateral nasal branch of the ganglion that runs downward and forward on the nasal septum. Entering the palate through the incisive canal, it is distributed to the incisive papilla and to the palate anterior to the anterior palatine nerve. Posterior superior alveolaris nerve Mandibular Nerve The mandibular nerve leaves the skull though the foramen ovale and almost immediately breaks up into its several branches. The chief branches; ¾ the inferior alveolar nerve, it gives off branches to the molar and premolar teeth and their supporting bone and soft tissues. Lingual nerve Muscles The masticatory muscles concerned with mandibular movements include • the lateral pterygoid, • digastric, • masseter, • medial pterygoid, • temporalis muscles. Masseter Muscle The masseter muscle has a function of : • clenching • sometimes active in facial expression • active during forceful jaw closing • may assist in protrusion of the mandible 23 Medial Pterygoid Muscle The medial pterygoid muscle arises from the medial surface of the lateral pterygoid plate and from the palatine bone. The principal functions of the medial pterygoid muscle are: • Elevation and lateral positioning of the mandible. Historically the term eruption has been used to denote emergence of the tooth through the gingiva although it denotes more completely continuous tooth movement from the dental bud to occlusal contact. Calcification or mineralization (most often visualized radio graphically) of the organic matrix of a tooth, root formation, and tooth eruption are important indicators of dental age.
If no significant response cheap 160mg malegra fxt plus with mastercard, switch to another appropriate drug 160mg malegra fxt plus overnight delivery, and again increase until seizure control or toxicity D trusted malegra fxt plus 160 mg. Acute variants a) Disseminated (Marburg) b) Concentric sclerosis (Balo) c) Neuromyelitis optica (Devic) B generic malegra fxt plus 160 mg mastercard. Classical a) Postinfectious encephalomyelitis b) Postvaccinal encephalomyelitis 2. It is a compact multilammellar membrane spiral that in electron micrographs appears as alternating dark and light lines. The dark or "major dense" lines represent the apposition of the cytoplasmic aspects of the oligodendrocyte or Schwann cell membrane; the light "interperiod" line represents the apposition of the extracellular membrane faces. Ensheathment of axons by myelin permits the rapid "saltatory conduction" of action potentials. Diseases affecting the myelin sheath interfere with normal conduction and cause signs and symptoms referable to the specific parts of the nervous system involved. Myelin is susceptible to a number of disease processes, and there are several ways of classifying diseases involving myelin. Primary diseases of myelin are those in which the myelin sheaths (or their oligodendrocytes or Schwann cells) are involved but axons are relatively preserved. A pathology-based classification divides these diseases into four broad categories: demyelination, dysmyelination, hypomyelination and myelinolysis. Demyelinating diseases are generally inflammatory, sporadic, and characterized by the immune-mediated destruction of biochemically normal myelin and its supporting cells; axons are generally spared. Dysmyelinating diseases (leukodystrophies) are generally non-inflammatory, familial, and characterized by the confluent destruction of (presumably) chemically abnormal myelin and its supporting cells; axonal loss is more prevalent than in demyelinating or myelinolytic diseases. Involvement of both central (especially cerebral) and peripheral myelin may occur, reflecting the biochemical similarities of these myelins. In hypomyelinating diseases, there is a similar confluent abnormality in white matter, but there is a general paucity of myelin deposition during development. Thus, there is a reduced quantity if myelin lipids and proteins rather than the chemically abnormal myelin seen in the dysmyelinating diseases. Although the myelin is chemically normal in these diseases, they are often categorized as leukodystrophies due to the diffuse nature of the process. Myelinolytic diseases are non- inflammatory and characterized by intramyelinic edema of chemically normal myelin with relative sparing of the supporting cells and axons, at least in the early stages. Intramyelinic edema is recognized as a splitting of the myelin sheath at the interperiod line. More detailed descriptions of these and other diseases of myelin can be found in the supplementary reading. It is the prototypic and most frequently encountered demyelinating disease in humans. The prevalence varies with genetic background and latitude and usually affects young people (20-40 years of age), particularly women. Such attacks are followed by complete or partial remission and subsequent relapses ("chronic relapsing" multiple sclerosis). Attacks appear to be precipitated by infection, trauma, pregnancy or excessive heat; however controlled studies often fail to confirm these observations. The earliest presentation may be that of a young woman who complains of paresthesias or visual difficulties and yet, when tested, does not show any objective abnormalities (signs). There is no completely reliable laboratory test available at the present time to diagnose these patients at their initial presentation, however several types of tests are helpful in supporting this diagnosis. Evoked potentials (visual, auditory, and somatosensory) can also help demonstrate clinically silent lesions. Analysis of cerebrospinal fluid frequently shows evidence of inflammation (mild mononuclear pleocytosis, elevated IgG levels or oligoclonal IgG bands on electrophoresis) or myelin breakdown (elevated myelin basic protein levels). Sites of predilection include the pial surface of the optic nerves and chiasm, spinal cord and basis pontis and the periventricular white matter of the cerebrum, cerebellum and brainstem - that is, regions in proximity to cerebrospinal fluid and to deep cerebral veins. The gross and microscopic appearances of demyelinative plaques vary with their age. Whether oligodendrocytes are lost at this early stage is still a matter of debate, but most evidence indicates that the loss of oligodendrocytes follows damage to myelin. The perivenular myelinated axons appear to be affected first (perivenous demyelination) and are in immediate physical contact with macrophages, which are presumed to cause separation and thinning of myelin lamellae. Reactive astrocytosis is also prominent at this stage, but lipid-laden macrophages appear later. The risk of the disease is highest in monozygotic twins and increased in first degree relatives compared to nonrelated individuals. This association is believed to confer an immune responsiveness to whatever the etiologic antigen may be. People living in northerly latitudes (colder climates) have a higher prevalence (northern U. Some argue that this is related to similar genetic backgrounds of people living in the northern latitudes of Europe and North 117 America. A second environmental factor appears to be an infectious agent that is contracted before the age of 15 years. Measles virus remains the most persistent contender, but a retrovirus may be the culprit. This autoreactivityis thought to be precipitated by exposure to an infectious agent early in life. Acute Disseminated Encephalomyelitis In contrast to multiple sclerosis, this disease is uncommon, affects children more than adults and is usually seen following a viral infection or vaccination. The onset is acute and typically there is diffuse involvement of the brain, spinal cord and meninges. Postinfectious encephalomyelitis most commonly follows measles (rubeola) infection. The majority of patients with postinfectious encephalomyelitis completely recover, if appropriately treated with steroids, while approximately 10% die and approximately 10% demonstrate persistent deficits. Historically, the most important causes of postvaccinal encephalomyelitis are rabies vaccines produced in brain tissue (no longer done in this country) and smallpox vaccine (no longer administered). The prognosis in these patients is similar to those with postinfectious encephalomyelitis. However, inflammatory cells are largely lymphocytes and discrete perivenous lesions are the rule rather than the exception. This pathogenesis of acute disseminated encephalomyelitis appears to represent an immune destruction of myelin, which is not dependent upon direct invasion of the brain by virus. Experimental allergic encephalomyelitis, an autoimmune, inflammatory demyelinating disease, 118 appears to be an excellent model for this human disease. Acute hemorrhagic leukoencephalitis Acute hemorrhagic leukoencephalitis (Weston Hurst disease) is thought to be an hyperacute form of acute disseminated encephalomyelitis. This usually occurs in childhood and there may be an antecedent viral infection (influenza, chicken pox, measles) or a vaccination. The onset is dramatic and often asymmetric due to the predominance of lesions in one cerebral hemisphere. Pathologically, these lesions are characterized by necrosis of blood vessels with a marked fibrinous exudate, ring-shaped hemorrhages and neutrophilic inflammatory cells. Grossly, the lesions are variable in size, multiple, granular and usually restricted to the deep white matter. Microscopically, primary demyelination with marked, often bizarre, astrocytosis is observed. Oligodendrocytes are diminished within the lesions; their nuclei are enlarged and exhibit amphophilic viral inclusions. Viral antigens and particles have been demonstrated in these inclusions and rarely in the bizarre astrocytes. Although the reactivation of a latent virus appears to play a fundamental role, it must be emphasized that both the chronicity of its clinical course ("slow infection") and the lack of immune and inflammatory host responses set this disease apart from classical latent infections, such as varicella-zoster. This disease entity is illustrated in the infectious disease section of this syllabus.
Typically 160mg malegra fxt plus for sale, spinal nerve systems that connect to the brain are contralateral purchase 160 mg malegra fxt plus overnight delivery, in that the right side of the body is connected to the left side of the brain and the left side of the body to the right side of the brain order malegra fxt plus 160mg without a prescription. Cranial Nerves Cranial nerves convey specific sensory information from the head and neck directly to the brain order malegra fxt plus 160mg on line. For sensations below the neck, the right side of the body is connected to the left side of the brain and the left side of the body to the right side of the brain. Whereas spinal information is contralateral, cranial nerve systems are mostly ipsilateral, meaning that a cranial nerve on the right side of the head is connected to the right side of the brain. Some cranial nerves contain only sensory axons, such as the olfactory, optic, and vestibulocochlear nerves. Other cranial nerves contain both sensory and motor axons, including the trigeminal, facial, glossopharyngeal, and vagus nerves (however, the vagus nerve is not associated with the somatic nervous system). A simple case is a reflex caused by a synapse between a dorsal sensory neuron axon and a motor neuron in the ventral horn. More complex arrangements are possible to integrate peripheral sensory information with higher processes. Spinal Cord and Brain Stem A sensory pathway that carries peripheral sensations to the brain is referred to as an ascending pathway, or ascending tract. Tactile and other somatosensory stimuli activate receptors in the skin, muscles, tendons, and joints throughout the entire body. However, the somatosensory pathways are divided into two separate systems on the basis of the location of the receptor neurons. Somatosensory stimuli from below the neck pass along the sensory pathways of the spinal cord, whereas somatosensory stimuli from the head and neck travel through the cranial nerves—specifically, the trigeminal system. The dorsal column system (sometimes referred to as the dorsal column–medial lemniscus) and the spinothalamic tract are two major pathways that bring sensory information to the brain (Figure 14. As axons of this pathway enter the dorsal column, they take on a positional arrangement so that axons from lower levels of the body position themselves medially, whereas axons from upper levels of the body position themselves laterally. The dorsal column is separated into two component tracts, the fasciculus gracilis that contains axons from the legs and lower body, and the fasciculus cuneatus that contains axons from the upper body and arms. The axons in the dorsal column terminate in the nuclei of the medulla, where each synapses with the second neuron in their respective pathway. The nucleus gracilis is the target of fibers in the fasciculus gracilis, whereas the nucleus cuneatus is the target of fibers in the fasciculus cuneatus. The second neuron in the system projects from one of the two nuclei and then decussates, or crosses the midline of the medulla. These axons terminate in the thalamus, where each synapses with the third neuron in their respective pathway. The third neuron in the system projects its axons to the postcentral gyrus of the cerebral cortex, where somatosensory stimuli are initially processed and the conscious perception of the stimulus occurs. These neurons extend their axons to the dorsal horn, where they synapse with the second neuron in their respective pathway. The name “spinothalamic” comes from this second neuron, which has its cell body in the spinal cord gray matter and connects to the thalamus. Axons from these second neurons then decussate within the spinal cord and ascend to the brain and enter the thalamus, where each synapses with the third neuron in its respective pathway. The neurons in the thalamus then project their axons to the spinothalamic tract, which synapses in the postcentral gyrus of the cerebral cortex. These two systems are similar in that they both begin with dorsal root ganglion cells, as with most general sensory information. The dorsal column system is primarily responsible for touch sensations and proprioception, whereas the spinothalamic tract pathway is primarily responsible for pain and temperature sensations. Another similarity is that the second neurons in both of these pathways are contralateral, because they project across the midline to the other side of the brain or spinal cord. In the dorsal column system, this decussation takes place in the brain stem; in the spinothalamic pathway, it takes place in the spinal cord at the same spinal cord level at which the information entered. In both, the second neuron synapses in the thalamus, and the thalamic neuron projects to the somatosensory cortex. The trigeminal pathway carries somatosensory information from the face, head, mouth, and nasal cavity. As with the previously discussed nerve tracts, the sensory pathways of the trigeminal pathway each involve three successive neurons. The spinal trigeminal nucleus of the medulla receives information similar to that carried by spinothalamic tract, such as pain and temperature sensations. Other axons go to either the chief sensory nucleus in the pons or the mesencephalic nuclei in the midbrain. These nuclei receive information like that carried by the dorsal column system, such as touch, pressure, vibration, and proprioception. Axons from the third neuron then project from the thalamus to the primary somatosensory cortex of the cerebrum. The sensory pathway for gustation travels along the facial and glossopharyngeal cranial nerves, which synapse with neurons of the solitary nucleus in the brain stem. Finally, axons from the ventral posterior nucleus project to the gustatory cortex of the cerebral cortex, where taste is processed and consciously perceived. The sensory pathway for audition travels along the vestibulocochlear nerve, which synapses with neurons in the cochlear nuclei of the superior medulla. Within the brain stem, input from either ear is combined to extract location information from the auditory stimuli. Whereas the initial auditory stimuli received at the cochlea strictly represent the frequency—or pitch—of the stimuli, the locations of sounds can be determined by comparing information arriving at both ears. Sound localization is achieved by the brain calculating the interaural time difference and the interaural intensity difference. A sound originating from a specific location will arrive at each ear at different times, unless the sound is directly in front of the listener. If the sound source is slightly to the left of the listener, the sound will arrive at the left ear microseconds before it arrives at the right ear (Figure 14. Also, the sound will be slightly louder in the left ear than in the right ear because some of the sound waves reaching the opposite ear are blocked by the head. Connections between neurons on either side are able to compare very slight differences in sound stimuli that arrive at either ear and represent interaural time and intensity differences. Axons from the inferior colliculus project to two locations, the thalamus and the superior colliculus. The medial geniculate nucleus of the thalamus receives the auditory information and then projects that information to the auditory cortex in the temporal lobe of the cerebral cortex. The superior colliculus receives input from the visual and somatosensory systems, as well as the ears, to initiate stimulation of the muscles that turn the head and neck toward the auditory stimulus. An important function of the vestibular system is coordinating eye and head movements to maintain visual attention. Some axons project from the vestibular ganglion directly to the cerebellum, with no intervening synapse in the vestibular nuclei. The cerebellum is primarily responsible for initiating movements on the basis of equilibrium information. One target is the reticular formation, which influences respiratory and cardiovascular functions in relation to body movements. A second target of the axons of neurons in the vestibular nuclei is the spinal cord, which initiates the spinal reflexes involved with posture and balance. To assist the visual system, fibers of the vestibular nuclei project to the oculomotor, trochlear, and abducens nuclei to influence signals sent along the cranial nerves. Finally, the vestibular nuclei project to the thalamus to join the proprioceptive pathway of the dorsal column system, allowing conscious perception of equilibrium. During head movement, the eye muscles move the eyes in the opposite direction as the head movement, keeping the visual stimulus centered in the field of view. Instead of the connections being between each eye and the brain, visual information is segregated between the left and right sides of the visual field. In addition, some of the information from one side of the visual field projects to the opposite side of the brain.