Introduction
Movement in the body occurs due to coordination in the body parts, muscles, and brain. Various aspects of the body do involuntary activities just because the brain directs them. For movement to occur, the brain must be involved to work hand in hand with the muscles and neurons in the body. This paper explains a sequence of activities in the production of movement, the different cortices involved, and movement disorders which are myasthenia gravis and multiple sclerosis.
The sequence of activities in the production of movement
In response to brain signals, muscles contract. The sole method the brain communicates with muscles is through motor neurons, single nerve cells in the spinal cord. An impulse from a firing motor neuron in the spinal cord travels along an axon. An axon is a long, fragile extension of a single cell to the muscles. A substance is released at the end of the impulse’s path that goes through the axon to the muscle. An extension ladder’s two components can glide past one another and then lock into a particular position because forces are formed of long fibers connected by a continuation of mechanism. Every motor neuron attaches to a muscle, and the brain directs the muscles to move. In the cerebral cortex, there is a command to the neurons. The cortex is then connected to the spinal cord, which distributes the controls to the various muscles.
The roles of various motor cortices
The primary motor cortex encodes the direction of motion. The central motor cortex has many neurons explicitly directed in one order. A cell, for instance, might fire vigorously when the hand is moved to the left, but it might be inhibited when the hand is moved to the right. Primary motor cortex helps in both movement and learning.
The supplementary motor region has historically been assumed to be important for planning and producing successive movements(Ohbayashi, 2021). Speech, self-initiated movements, and sequential motions were all impaired in human patients with lesions that included these areas.
In numerous studies, the dorsal premotor cortex has been identified as the region responsible for the visual control of motor behavior. Additionally, it is hypothesized that the dorsal premotor cortex is involved in decision-making and mental rehearsal, two cognitive processes associated with visually directed motor activities (Ohbayashi, 2021). There is a lot of evidence to support the idea that the dorsal premotor cortex plays a special role in the direction of movements that are based on remembered arbitrary sensory associations.
Movement disorders
A neuromuscular autoimmune disease called myasthenia gravis is characterized by poor nerve-muscle communication. Skeletal muscles become weak as a result of this disorder. Progressive nerve damage is a hallmark of the chronic neurological illness known as multiple sclerosis. However, the two disorders have some similarities and differences.
Similarities and differences between myasthenia gravis and multiple sclerosis
Both disorders affect the skeletal muscles. To diagnose myasthenia and multiple sclerosis, a doctor has to conduct a physical exam. Myasthenia mostly affects people who are 40 to 60 years of age and can affect any race. On the other hand, multiple sclerosis affects people of white descent especially women of age 20 to 60. In myasthenia, medication and surgery can help reduce medical and chronic response (Herode & Borenstein, 2005, p. 2). On the other hand in multiple sclerosis, therapists can help modify the disease.
Role of genetics and the environment in the occurrence of myasthenia gravis and multiple sclerosis
An autoimmune neurological condition called myasthenia gravis is characterized by faulty neuromuscular junction signaling. The majority of researchers have connected myasthenia gravis to a hereditary condition. Myasthenia gravis often does not run in families and affects persons who have never had the condition. About 3 to 5 percent of those who are afflicted have family relatives who also have myasthenia gravis, although the pattern of inheritance is unknown(Herode & Borenstein, 2005, p. 3). The risk of MS has, however, been frequently and persistently linked to a number of environmental variables, including exposure to cigarette smoking, less exposure to sunlight and obesity in children.
Conclusion
In other words, multiple sclerosis is not a condition that is handed on from one generation to the next by inheritance. But MS has a hereditary risk that might be passed down through the family. A probability of 1 in 750 to 1000 people in the whole population will acquire Multiple sclerosis. A issue with the impulses conveyed between the muscles and the nerves is what causes myasthenia gravis. It is an autoimmune disorder, which implies that the immune system the body’s natural defense against infection inadvertently attacked a healthy area of the body.
References
Herode, A., & Borenstein, S. (2005). Multiple sclerosis and myasthenia gravis. Immunological and Clinical Aspects of Multiple Sclerosis, 337-341. doi:10.1007/978-94-011-6352-1_63
Ohbayashi, M. (2021, June 9). The roles of the cortical motor areas in sequential movements. Retrieved from https://www.frontiersin.org/articles/10.3389/fnbeh.2021.640659/full
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