Clinical Application Quiz#3 Open Resource Name_______________________________ Feel free to use additional paper if needed. 1. A client is admitted to the hospital with weakness in his legs, double vision, tingling in the arms, difficulty speaking, and tremor. He was diagnosed with multiple sclerosis, and told that the disease was due to the degeneration of the myelin sheath. The loss of the myelin sheath would cause these symptoms because without the sheath what specific things happen to the axons ability to perform. the loss of myelin, which is the material that coats nerve cells (the loss of myelin is called demyelination). Myelin is an insulating substance which is wrapped around nerves in the body, serving to speed conduction of nerve impulses. Without myelin, nerve conduction slows or stops. 2. If the resting membrane potential is -70 mV and the threshold is -55mV, a membrane potential of -60mV will cause what to occur in the neuron? depolarization 3. How is a strong nerve stimulus coded for by action potentials if all action potentials are identical? 4. Cancer is a genetic problem in which genes that control mitosis have been mutated. As a result, the cancerous cell will divide uncontrollably. Many cell types develop cancer but neurons do not. The reason is that neurons don’t divide. 5. Which of the following statements is false? 1. the epidural space contains cerebrospinal fluid 2. the subarachnoid space contains fat 3. the dura mater is the thickest outer meninge 4. the subdural space contains blood 6. Mr. J. R. was injured in an accident, resulting in trauma to the motor arm of the reticular formation. What symptom(s) would you expect to see? Somatic motor control - Some motor neurons send their axons to the reticular formation nuclei, giving rise to the reticulospinal tracts of the spinal cord. These tracts function in maintaining tone, balance, and posture--especially during body movements. The reticular formation also relays eye and ear signals to the cerebellum so that the cerebellum can integrate visual, auditory, and vestibular stimuli in motor coordination. Other motor nuclei include gaze centers, which enable the eyes to track and fixate objects, and central pattern generators, which produce rhythmic signals to the muscles of breathing and swallowing. 7. While working in the emergency room, you receive two patients who were in an auto accident. One is dead on arrival, having suffered a transaction (severing injury) of the spinal cord at the level of C2. The other patient suffered a similar injury, but at the level of C6, and is still alive. In terms of phrenic nerve origin and function, why was one injury fatal and the other not? C2 is not a phrenic nerve. People with injuries at the top, close to the brain at the C1 or C2 level, often die. If they survive, they usually need a respirator to help them breath. 8. While walking down the street, you get startled by a passing car that honks its horn right next to you. Your response is to jump away from the noise. What part of the brain was the primary center involved in this reflex motion? Inferior colliculi- are part of the auditory relay from the hearing receptors of the ear to the sensory cortex. They also act in reflexive response to sound, such as startle reflex which causes you to turn your head towards an unexpected noise. 9. Lillie’s automobile is hit at an angle on the freeway by another car. On impact, her head slams into the window causing her to black out. It is later assessed by the ER physician that she has received major injury to her cerebellum due to the whiplash. Knowing what you do about the cerebellum, list the symptom(s) Lillie will most likely experience. Jerky body movements and difficulty walking in a straight line 10. If the ventral root of a spinal nerve arising from the thoracic region were cut, what would be the result in the tissue or region that nerve supplies? Cutting the ventral root of a spinal nerve will denervate all target organs that receive efferent innervation from that spinal nerve. Spinal nerves are made by the joining of dorsal and ventral roots of a spinal cord segment. Dorsal roots generally carry sensory information, while ventral roots generally carry motor innervation. Another way to say this is that dorsal roots carry information from the periphery to the central nervous system (CNS) in an afferent direction, while ventral roots carry information from the CNS to the periphery in an efferent direction. Afferent information is generally sensory in nature, while efferent information includes signals to trigger muscular contraction as well as gland secretion, hormone synthesis, etc.
Posted on: Sun, 16 Jun 2013 23:13:41 +0000
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