Healthcare and Reflex pathways

Reflex pathways
Introduction
Reflexes or reflex pathways are always most easily observed as well as analyzed specifically when the spinal cord directly receives a synchronous volley, particularly of afferent input. Due to such an occurrence, the afferent volley often has been provoked specifically by electrical stimulation associated with nerves, rather than particularly by the natural stimulation associated with peripheral receptors (Goldberger, 2019). The result in most cases is always that several reflex stimuli, especially in various animal experiments, become described specifically in terms of the specific intensity of the electrical stimulation associated with the nerve, rather than particularly in terms of which the sensory receptors have majorly been activated.
Fortunately, in the muscle nerves, there always exists a fairly close specific relationship between the particular electrical stimulation threshold associated with fiber together with the sensory receptor that it innervates (Horn, 2019). This paper aims to explore the reflex pathways by focusing specifically on the patellar tendon reflex pathway, how the intensity of the reflex pathway response becomes affected and sharing of the reflex pathway of any other reflex of choice.
This week you will learn about reflex pathways. One classic example is the patellar tendon reflex. Please, describe the pathway of this reflex.
When the patellar tendon becomes tapped just directly below the knee, the particular tap often initiates an action that is potential in a specific specialized structure that is referred to as a muscle spindle, that is located specifically within the quadriceps. Such an action potential often travels directly to the L3 together with L4 nerve roots associated with the spinal cord through a sensory axon that often chemically communicates specifically by releasing glutamate directly onto the motor nerve (Goldberger, 2019). The result, specifically of such a motor nerve associated activity involves the contraction of the specific quadriceps muscle, which often leads to the extension of the particular lower leg specifically at the knee. In such a situation, the lower leg often kicks forward. Ultimately, an improper related patellar reflex may mainly indicate a central nervous system (CNS) injury.
The sensory input specifically from the quadriceps usually activates local interneurons which release the inhibitory associated neurotransmitter glycine onto the motor neurons associated with the antagonist's muscles, specifically blocking the particular sustained stimulation of such antagonistic (hamstring) muscles (Marieb, 2018). The relaxation associated with the opposing muscle often facilitates mostly by not specifically opposing the extension associated with the lower leg. In several lower animals, the reflex interneurons in most cases do not necessarily or particularly reside in the spinal cord, for instance as in the specific lateral giant neuron particularly of crayfish.
Also, since the brain (CNS) is not directly involved in the reflex pathway, how will the intensity of the response be affected?
Since the brain (CNS) is not directly involved in the reflex pathway when it comes to stimulus intensity as well as information processing, the physiological, as well as behavioral responses, always effect stimulus intensity associated with the time course associated with information processing (Kenneth, 2017). The physiological responses always show the intensity effects on the particular sensory pathway. In most cases, the reaction time studies often show that the specific effect associated with intensity on the behavioral responses as well depends on and sometimes may be mediated specifically by several cognitive processes.
The specific degree to which the intensity affects a simple reaction time often varies directly and specifically with a response criterion-associated subjects use. The specific lack of such dependence in the choice reaction time in most cases may indicate a different intensity effect, particularly on energy together with non-energy pathways (Goldberger, 2019). The intensity often affects the specific time course associated with information processing not just by influencing the specific speed associated with processing in sensory pathways majorly, but also through affecting the alertness together with the time that is required to direct the attention to the stimulus.
Feel free to share the reflex pathway of any other reflex of your choice.
Crossed Extensor Reflex
The crossed extensor reflex specifically involves a withdrawal reflex. The crossed extensor reflex often occurs specifically when the flexors specifically in the withdrawing limb directly contract and the specific extensors relax, while particularly in the other particular limb, the opposite directly occurs (Horn, 2019). An example of such involves when someone steps directly on a nail, where the leg which steps on the nail immediately pulls away, while in the process, the other leg specifically takes the weight associated with the whole body.
The crossed extensor reflex often is known to be contralateral, meaning that the reflex occurs specifically on the opposite side associated with the body specifically from the stimulus (Marieb, 2018). To produce such reflex, various branches associated with the afferent nerve fibers often cross from the specific stimulated body side to the particular contralateral side specifically of the spinal cord. As a result, there occurs a synapse with interneurons, that in turn, often excite and inhibit the alpha motor neurons specifically to the muscles associated with the contralateral limb.
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Influence of Age on Patellar Tendon Reflex Response.
The significant finding associated with such a study confirms a specific decline in the magnitude of the particular reflex response with the increasing age. The differences in most situations can become best observed specifically at a specific tapping angle of about 45u (Chandrasekhar, 2013). This result often suggests that age in most cases is an essential factor which always influences the particular reflex response of various individuals, where the extent particularly to which the specific reflex response becomes majorly affected has often been quantified specifically in terms of the knee angles.
This study as well suggests that gender, together with limb position of either right or left side in most situations never has a significant impact specifically on the magnitude associated with reflex response (Chandrasekhar, 2013). The findings associated with such a study are always believed to have a potential specifically to majorly contribute to the particular development of an associated evidence base which possibly could help various physicians perform several more accurate reflex assessments.
Assessment of Patellar Tendon Reflex Responses Using Second-Order System Characteristics. Applied bionics and biomechanics.
Deep associated tendon reflex tests including the patellar tendon reflex (PTR), in most cases often become widely accepted necessarily as simple examinations specifically for detecting various neurological disorders (Steineman, 2016). Despite a common acceptance, the grading scales often remain subjective, which in the end usually create an opportunity for the quantitative measures to particularly improve the reliability as well as the efficacy of such tests. Previous studies have greatly demonstrated the usefulness associated with quantified measurement variables.
In the current study, it has been hypothesized that the patellar tendon reflex responses may become specifically described by an exponential decay rate as well as a damped natural frequency associated with a theoretically associated second-order system (Steineman, 2016). Kinematic data were specifically recorded from both the knees of about 45 subjects using a specific motion capture system as well as correlation analysis, where as a result, it was found that the specific mean R2 value specifically was 0.99.
Exponential decay rate together with damped natural frequency ranges specifically determined from such sample population were ?5.61 up to ?1.42 and 11.73?rad/s up to 14.96?rad/s, respectively (Steineman, 2016). This study directly confirmed that patellar tendon reflex responses strongly correlate specifically to the second-order system in most cases and that the exponential decay rate, as well as undamped natural frequency in many situations, are the novel measurement variables that can be effectively used to measure patellar tendon reflex responses accurately. As a result, further investigation associated with such measurement variables together with their usefulness when it comes to grading patellar tendon reflex responses is warranted.
Conclusion
In conclusion, a reflex action or a reflex involves an involuntary as well as nearly instantaneous movement specifically in response to a stimulus. When someone accidentally touches a particular hot object, such a person may automatically jerk their particular hand away immediately without thinking. A reflex specifically never requires any particular thought input. The path which is often taken by the specific nerve impulses specifically in a reflex always is known as a reflex arc. In the higher animals, several sensory neurons never pass directly or specifically into the brain, but basically, synapse particularly in the spinal cord.
Such a characteristic often allows reflex actions immediately to occur quite relatively quickly through the activation of the spinal motor neurons particularly without delay associated with routing signals specifically through the brain, although the specific brain will eventually receive sensory input while the particular reflex action occurs. Most reflex arcs often involve only three major neurons. The stimulus, like a needle stick, which stimulates the specific pain receptors associated with the skin, often initiate an impulse specifically in sensory neurons.
The impulse travels to the specific spinal cord where it directly passes through the means of synapses, specifically to the connecting neuron known as the relay neuron that is often situated in the spinal cord. The particular relay neuron in response or turn often makes a synapse specifically with one or sometimes more motor neurons which usually transmit the impulse directly to the muscles associated with the limb causing them particularly to contract or pull away specifically from the particular sharp object. Reflexes never require involvement or engagement of the brain. However, in some situations, the brain may prevent reflex action.
References
Chandrasekhar, A., Abu Osman, N. A. Tham, L. K., Lim, K. S., & Wan Abas, W. A. (2013). Influence of age on patellar tendon reflex response. PloS one, 8(11), e80799. doi:10.1371/journal.pone.0080799.
Goldberger, J. J., Arora, R., Buckley, U., & Shivkumar, K. (2019). Autonomic nervous system dysfunction: JACC focus seminar. Journal of the American College of Cardiology, 73(10), 1189-1206.
Horn, C. C., Ardell, J. L., & Fisher, L. E. (2019). Electroceutical targeting of the autonomic nervous system. Physiology, 34(2), 150-162.
Kenneth, S. S. (2017). Anatomy & Physiology: The unity of form and function. McGraw-Hill.
Marieb, E. & Hoehn, K. (2018). Human Anatomy & Physiology (11th ed). Boston, MA: Pearson. ISBN: 9780134756363
Steineman, B. D., Karra, P., & Park, K. (2016). Assessment of Patellar Tendon Reflex Responses Using Second-Order System Characteristics. Applied bionics and biomechanics, 2016, 7172948. doi:10.1155/2016/717292948. http://downloads.hindawi.com/journals/abb/2016/7172948.pdf