Names, Functions, and Locations of Cranial Nerves

Names, Functions, and Locations of Cranial Nerves The cranial nerves are nerves that arise from the brain and exit the skull through holes (cranial foramina) at its base rather than through the spinal cord. Peripheral nervous system connections with various organs and structures of the body are established through cranial nerves and spinal nerves. While some cranial nerves contain only sensory neurons, most cranial nerves and all spinal nerves contain both motor and sensory neurons. Function Cranial nerves are responsible for the control of a number of functions in the body. Some of these functions include directing sense and motor impulses, equilibrium control, eye movement and vision, hearing, respiration, swallowing, smelling, facial sensation, and tasting. The names and major functions of these nerves are listed below. Olfactory Nerve: Sense of smellOptic Nerve: VisionOculomotor Nerve: Eyeball and eyelid movementTrochlear Nerve: Eye movementTrigeminal Nerve: This is the largest cranial nerve and is divided into three branches consisting of the ophthalmic, maxillary and mandibular nerves. Functions controlled include facial sensation and chewing.Abducens Nerve: Eye movementFacial Nerve: Facial expressions and sense of tasteVestibulocochlear Nerve: Equilibrium and hearingGlossopharyngeal Nerve: Swallowing, sense of taste, and saliva secretionVagus Nerve: Smooth muscle sensory and motor control in throat, lungs, heart, and digestive systemAccessory Nerve: Movement of neck and shouldersHypoglossal Nerve: Movement of tongue, swallowing, and speech Location The cranial nerves consist of 12 paired nerves that arise from the brainstem. The olfactory and optic nerves arise from the anterior portion of the brain called the cerebrum. The oculomotor and trochlear cranial nerves stem from the midbrain. The trigeminal, abducens, and facial nerves arise in the pons. The vestibulocochlear nerve arises in the inner ears and goes to the pons. The glossopharyngeal, vagus, accessory and hypoglossal nerves are attached to the medulla oblongata. Sensory Cranial Nerves Snellen chart test assesses visual acuity and optic nerve function. CentralITAlliance/iStock/Getty Images Plus There are three sensory cranial nerves: olfactory (I), optic (II), and vestibulocochlear (VIII). These cranial nerves are responsible for our senses of smell, vision, hearing, and equilibrium. Medical professionals test cranial nerve I by having a person close their eyes and one nostril while inhaling a scent such as coffee or vanilla. An inability to recognize a scent may indicate problems with the sense of smell and cranial nerve I. Central and peripheral vision are under the control of optic nerve (II). Examiners test visual acuity using a Snellen chart. Vestibulocochlear nerve (VIII) functions in hearing and can be assessed with the whisper test. The examiner stands behind the person and whispers a sequence of letters into one ear while the person holds a hand over the non-tested ear. The process is repeated with the opposite ear. Ability to repeat the whispered words indicate proper function. Motor Cranial Nerves Motor nerves function in movement of anatomical structures. Motor cranial nerves include the oculomotor (III), trochlear (IV), abducens (VI), accessory (XI), and hypoglossal (XII) nerves. Cranial nerves III, IV, and VI control eye movement. The oculomotor nerve controls pupil constriction and is assessed using a penlight. Light is briefly advanced from the outer edge of the eye to the center of the eye and pupil responses are observed. The trochlear and abducens nerves are often tested by having a person follow an examiners finger movements with his or her eyes only. The accessory nerve controls movement of the neck and shoulders. It is tested by having a person shrug his or her shoulders and turn their head from side to side against resistance from the the examiners hand. The hypoglossal nerve controls movement of the tongue, swallowing, and speech. Assessment of this nerve involves asking the person to stick out his or her tongue to ensure that it is midline. Mixed Cranial Nerves   normaals/iStock/Getty Images Plus Mixed nerves have both sensory and motor function. Mixed cranial nerves include the trigeminal (V), facial (VII), glossopharyngeal (IX), and vagus (X) nerves. The trigeminal nerve is the largest cranial nerve and is involved in facial sensation, chewing, and corneal reflex. Facial sensations are often checked by rubbing soft and blunt objects on various areas of the face. Chewing is typically tested by having the person open and close his or her mouth. The facial nerve controls facial expressions and is involved in taste sensation. This nerve is commonly tested by observing for facial symmetry. The glossopharyngeal nerve plays a role in swallowing, sense of taste, and saliva secretion. The vagus nerve is involved in smooth muscle sensory and motor control in the throat, lungs, heart, and digestive system. Cranial nerves IX and X are typically assessed together. The person is asked to say ah while the examiner observes movement of the palate. Swallowing ability and the ability to tast e different foods are also tested. Sources Facing Cranial Nerve Assessment. American Nurse Today, 17 May 2019, www.americannursetoday.com/facing-cranial-nerve-assessment/.  Seladi-Schulman, Jill. The 12 Cranial Nerves. Healthline, Healthline Media, www.healthline.com/health/12-cranial-nerves.

Canadian-American Relations Essay Example | Topics and Well Written Essays - 1500 words

Canadian-American Relations - Essay Example History has made us friends. Economics has made us partners. And necessity has made us allies. Those whom nature hath so joined together, let no man put asunder" (U.S. President John F. Kennedy).The cold war further strengthened the friendship between the two nations. Sharing the longest border, the two nations although face modern difficulties such as immigration, environmental concerns, trade disputes and many other issues, the two countries have had significant interoperability within the defense sphere and are today the world's largest trading partners. The United States and Canada expanded their formal military links at the operational level in the post world war period. The PJBD dealt with the political aspects of the defense relationships. A new body, the Military Cooperation Committee (MCC), was instituted to manage joint military planning between the American and the Canadian forces. Careful of surprise attacks after Pearl Harbor and concerned about the power of an increasingly hostile Soviet Union, American and Canadian defense officials used the bi-national planning structure of the MCC to set up the first joint continental defense initiative in 1946 called the Basic Security Plan (BSP). The Canadian Department of External Affairs (DEA) objected to the fact that it was denied access to the BSP working group by reason of its purported secrecy. The BSP was approved by both the United States and Canada in spite of these reservations. The PJBD and the MCC established a precedent of formal relations between Canada and the United States, providing for the coordinated defense of the continent. In 1949, Canada, the United States and their European allies formed the North Atlantic Treaty Organization (NATO). Canada and the United States were accorded their own Canada-US Regional Planning Group (CUSRPG) to look over the defense of North America within the larger NATO structure. American planners were eager to get on with this new undertaking. But the Canadian government of Louis St. Laurent was hesitant. At issue for the Prime Minister and his Minister of Defense, Brook Claxton, were the implied costs and sovereignty infringements of a continental air defense expansion. The St. Laurent Liberals had experienced first-hand the American presence in Canada during the Second World War. Any suggestion by the United States of grander defense mechanisms invoked images of American soldiers on Canadian soil - and a corresponding loss of sovereignty. The Canadian military was seen to take a very different perspective. The Chiefs of Staff argued that the American concerns and recommendations were legitimate and Canada's involvement was absolutely indispensable. After the detonation of a massive thermonuclear device by the Soviet Union in 1953, the Canadian military officials implored Claxton and St. Laurent to reconsider their cautious approach. Ultimately, Claxton recognized that Washington's steadfastness left Ottawa with hardly any option. The geography of North America and the nature of Canada-US relations were such that Canadian involvement in an improved continental air d