Reflex and Special Senses

Topics: Ear, Eye, Nervous system Pages: 9 (2728 words) Published: September 9, 2012
Name: Stephanie Frost
Section: Bio 201

Lab Report: Reflex and Special Senses

Please fill out this report and submit it to the dropbox. Do not hand in your own form. It will not be graded and you will receive a zero for the lab.

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* Please note that although you do not hand in items in observations, it is very important to do these as you may see some of these items on future/associated lab quizzes or be asked about some of these concepts on unit assignments.*

Activity 1: Stretch Reflexes


A. Which muscles contract with the patellar reflex? Quadriceps What spinal level does this correspond to? L2, L3, and L4. B. What is the difference between hypo-reflexive and hyper-reflexive responses? (What do these indicate?) Hyperflexia is defined as an increased action of the reflexes.1 Hyperflexia (exaggerated response) results from damaged or diseased motor areas in the CNS.2Hypoflexia is defined as a diminished function of the reflexes. Hypoflexia (inhibited response) results from degeneration of nerve pathways, voluntary motor control, and other factors.2 1. Taber’s Cyclopedic Medical Dictionary

2. C. What can you conclude about the effect of mental distraction on reflex activity? As the test subject, I can conclude that metal distraction had no effect on my reflex activity. My reflexes were just as strong before the test as during. D. If a muscle is fatigued from exercise and you then test the associated reflex, do you think you will see a greater or lesser reflex? Explain your reasoning. Lesser reflex. According to Saladin, central fatigue causes the central nervous system to produce less signal output to the skeletal muscles. E. Describe the Achilles tendon test. The Thompson Test-The patient should lie prone on the examination table, flexing the knee on the injured side. The calf should be gently squeezed by the physician, who watches for plantar flexion in the patient's foot. If the foot moves, the tendon is presumed to be at least partially intact. No movement is indicative of rupture, and the test results are considered abnormal. If the Thompson test is equivocal, a sphygmomanometer should be placed on the patient's calf and inflated to 100 mm Hg. The affected foot should be dorsiflexed. The pressure will rise to approximately 140 mm Hg if the tendon is intact. In a patient with an Achilles rupture, only a flicker of movement on the pressure gauge is discernible with dorsiflexion. Or

This is most easily done with the patient seated, feet dangling over the edge of the exam table. If they cannot maintain this position, have them lie supine, crossing one leg over the other in a figure 4. Or, failing that, arrange the legs in a frog-type position. Identify the Achilles tendon, a taut, discrete, cord-like structure running from the heel to the muscles of the calf. If you are unsure, ask the patient to plantar flex (i.e. "step on the gas"), which will cause the calf to contract and the Achilles to become taut. Position the foot so that it forms a right angle with the rest of the lower leg. You will probably need to support the bottom of the foot with your hand. Strike the tendon directly with your reflex hammer. Be sure that the calf if exposed so that you can see the muscle contract. A normal reflex will cause the foot to plantar flex (i.e. move into your supporting hand). What spinal level does this correspond to? S1 & S2

Activity 2: The Crossed Extensor Reflex


A.What happened when you pricked the subject’s finger? The subject pulled away his hand real quick.

B.Would you expect this reflex to be fast? Why or...
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