Reflexes lab

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Reflexes lab
2014-10-03 18:08:23
physiology lab
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  1. Describe the five components of the simple reflex are that connects a stimulus to an appropriate response.
    • 1.Receptor: reacts to stimulus.
    • 2.sensory (afferent): conducts nerve impulses to different pathways towards CNS.
    • 3.integration center: one or more synapse in CNS.
    • 4.motor (efferent): nerve impulses along efferent pathway from integration center.
    • 5.effector: efferent impulses by contracting or secreting a product.
  2. Distinguish between a reflex arc and a reflex.
    • Reflex: a response to stimulus that acts to return body to homeostasis.
    • Reflex arc: neural pathway that controls an action reflex.
  3. Describe the stimulus and response in the patellar, Achilles tendon, and biceps-jerk reflexes.
    Patellar response indicates the muscle spindle, afferent and efferent neurons, neuromuscular junctions, and muscles are working properly.
  4. What is the difference in the plantar reflex in adults and neonates? What accounts for this difference?
    The plantar reflex in adults, the big toe is flexed and the adduction of other toes. In young babies, their normal response is abduction of the toes and dorsiflexion of the hallux. The difference in adult is pathological and results from lesions in the cerebrum or damage to pyramidil tracts. With infants it is because they are not neurologically matured.
  5. Describe an adaptive advantage of the facilitation of the patellar reflex.
    Initiates an action potential in a structure known as a muscle spindle that is located in the quadriceps. The action potential travels to the spinal cord, via sensory axon chemically communicates by releasing glutamate onto a motor nerve. Which causes the contraction of the quadriceps muscle leading to extension of the lower leg at the knee.
  6. For the pupillary reflex, describe the stimuli that causes constriction and dilation of the pupil. What parts of the autonomic nervous system control each?
    Exposure and inexposure to light.
  7. Describe the consensual pupillary reflex. What purpose does it serve?
    Consensual pupillary reflex is a normal present crossed reflex in which light directed at one eye causes the opposite pupil to contract. The purpose of the consensual pupillary reflex is to allow the testing of the sensory and motor functions of the eye.
  8. Describe the ciliospinal reflex. What purpose does it serve?
    Ciliospinal reflex consists of dilation of the ipsilateral pupil in response to pain applied to the neck, face, and upper trunk. If the right of the neck is subjected to a painful stimulus, the right pupil dilates. The purpose is to test the functioning of the brain stem and autonomic nervous system.
  9. Distinguish between a cranial reflex and a spinal reflex and provide an example of each.
    • 1.) Spinal reflex: the axons are afferent neurons that enter the meninges by way of the dorsal root of spinal nerves, pass the dorsal root ganglion and then enter the dorsal horn of the spinal cord. i.e: pulling your hand away from a hot object.
    • 2.) Cranial reflex: is a fast, involuntary response to a stimulus, it uses the brain stem as an integrating center. i.e: tracking movements of your eyes while reading something.
  10. Distinguish between an ipsilateral reflex and a contralateral reflex and provide an example of each.
    • Ispsilateral reflex is a responses that occurs on the same side. i.e: patellar reflex. 
    • Contralateral reflex meaning the reflexoccurs on the opposite side of the body from the stimulus. To produce this reflex, branches of the afferent nerve fibers cross from the stimulated side of the body to the contralateral side of the spinal cord.
    • i.e: Once their foot comes into contact with the nail, they put their weight down on the other leg and pull the other one back as a reflex.