The Jendrassik Reflection

841 Words 4 Pages
1. The Jendrassik maneuver played a major role on the patellar reflex. One of the prevailing hypotheses has to deal with the alpha-gamma co-activation theory. It states that the alpha motor neurons activates the motor tone, which leads to the spindles providing feedback to the brain. This process is done by the gamma motor neurons, who are in charge of controlling the stimulation of the cerebellum. Also, both the alpha and gamma motor neurons meet at the same effector muscles. Furthermore, when the extrafusal fibers of the muscle spindle contract, the intrafusal fibers change length in correlation to the muscle tone to activate the feedback to the brain, which is done by the gamma neurons. The feedback process is performed by afferent neurons …show more content…
The latencies of the reflexes with those of the reactions indicates that the reflexes occur much more quickly than do the voluntary reactions. As depicted by the bar graph, the latencies of both the natural reflex and the Jendrassik reflex are approximately around 0.08 sec. On the contrary, the latency of the reaction was around 0.2 sec, which was significantly slower. It is evident that there is a significant difference between both voluntary and involuntary reflexes and reactions. Reflexes are defined as being quick, involuntary, and predictable reactions to muscle stimulation. The reason these reflexes are so fast is because they are involuntary and do not involve any conscious thought. This offers a significant advantage of speed, but it leads to a significant disadvantage in which we are not allowed to control the reflex to decide whether or not it is even necessary. On the contrary, a reaction is determined on an individual basis. It depends on how fast someone can perceive the stimulus, and respond. Essentially, the pathways of both voluntary and involuntary reactions differ tremendously. Because the actions of reflexes are involuntary, they follow a much shorter pathway which essentially bypasses any critical thought of the action in the brain. A somatic reflex follow a reflex are in which signals travel along a certain pathway. It begins with the somatic receptors, where afferent nerve fibers carry the information from the receptor to the posterior horn of the spinal cord or to the brainstem. The information is then sent to an integrating center in the gray matter of the spinal cord or brainstem. In most reflex arcs, the integrating center includes one or more interneurons. The integrating center then issues the response via the efferent nerve fibers, which carry the response to the effectors which carry out the final response. The reflex pathway and reaction pathway differ in their integrating centers. Because the reaction occurs voluntarily, the

Related Documents