Compare and contract upper motoneurons and lower motoneurons. Discuss the organization of motor pathways and functions. Be sure to include: corticobulbar, corticospinal, pyramidal, extrapyramidal, direct and indirect and UMN and LMN and other related topics. Use at least three references. The facial muscles and voluntary body movements are controlled by the pyramidal system. The pyramidal system is comprised of two pathways: the corticobulbar tract and the corticospinal tract (Jones, 2015). McCaffrey (2014) states that the corticobulbar tract innervates muscular movement of the face and neck, while the corticospinal tract is responsible for transporting movement related signals to the spinal cord.
Motor commands are generated in the central nervous system (CNS) and must travel via upper motor neurons (UMN) and synapse with lower motor neurons (LMN) to reach the
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Gilman and Newman (2003) expound on the idea that LMN’s are influenced by corticospinal tract fibers and help to innervate the muscles in the extremities and trunk area. McCaffrey (2014) delves into this topic by explaining the method in which the axons belonging to the UMN’s lower from the corona radiata and internal capsule to the spinal cord. As these fibers reach the brainstem, Gilman and Newman (2003) explain that they enter the middle section of the cerebral peduncle. While the fibers pass through the base of the pons, the fiber bundles are divided by the pontine nuclei (McCaffrey, 2014). These corticospinal fibers are positioned in a ventral orientation while passing through the brainstem (Gilman and Newman, 2003). In addition, Watts (2014) explains that at the bottom portion of the medulla most fibers cross in a manner that is known as motor decussation, travel dorsally and then cross at midline. However, McCaffrey (2014) mentions that not all axons cross at
In the beginning phases of muscle contraction, a “cocked” motor neuron in the spinal cord is activated to form a neuromuscular junction with each muscle fiber when it begins branching out to each cell. An action potential is passed down the nerve, releasing calcium, which simultaneously stimulates the release of acetylcholine onto the sarcolemma. As long as calcium and ATP are present, the contraction will continue. Acetylcholine then initiates the resting potential’s change under the motor end plate, stimulates the action potential, and passes along both directions on the surface of the muscle fiber. Sodium ions rush into the cell through the open channels to depolarize the sarcolemma. The depolarization spreads. The potassium channels open while the sodium channels close off, which repolarizes the entire cell. The action potential is dispersed throughout the cell through the transverse tubule, causing the sarcoplasmic reticulum to release
In order for a body to move, a muscle has to be activated by an electrical impulse. The electrical impulse sends a message to the parietal lobe, frontal lobe, and cerebellum. The message then works its way through the spinal cord next to nerve pathways to the muscles which activate movement. Kinesthetic arts to stimulate motor activity. Motor activity is followed by swift thought processes that set goals, predict outcomes, analyze variables and complete movements.
Oatis C. (2009) Kinesiology: The Mechanics & Pathomechanics of Human Movement (Second ed.). Glenside, Pennsylvania: Lippincott Williams & Wilkins.
...t has been noted that the gate control theory proposed by Melzack and Wall in 1965 formed the foundation of understanding the process of pain signal transmission. The dorsal horn of the spinal cord is the region of the CNS that controls the passage of pain signals by means of opening and/or closing the gate. Pain can only be perceived if reaches the brain. Events that cause excitation such pain signals and the release of excitatory or facilitatory chemicals cause the gate to open whereas inhibitory events such as competing nerve impulses caused by rubbing trigger closure of the gate. The gate can also be closed due to descending inhibition enhanced by relaxation or the use of pain-relieving medication such as morphine. The brain stem is responsible for controlling the transmission of pain signals via the ascending and descending pain pathways.
The Pyramidal System controls the voluntary motor movement and is especially crucial in fine motor control. Spastic (hypertonic) cerebral palsy, the most common form cerebral palsy and is characterized by increased muscle tone that interferes with voluntary movement and fine motor movement, such as movement of the hand or fingers. The most common types of topographical types are diplegia, hemiplegia, double hemiplegia, and quadriplegia.
Firstly, there is various of sensing activities as in seeing and hearing as in a sense of understanding of what is seen and heard. Secondly the sense of feeling in numerous parts of the body from the head to the toes. The ability to recall past events, the sophisticated emotions and the thinking process. The cerebellum acts as a physiological microcomputer which intercepts various sensory and motor nerves to smooth out what would otherwise be jerky muscle motions. The medulla controls the elementary functions responsible for life, such as breathing, cardiac rate and kidney functions. The medulla contains numerous of timing mechanisms as well as other interconnections that control swallowing and salivations.
The MF-DCN synaptic plasticity mechanism was previously hypothesized to be a proper cerebellar gain controller which self-adapts its maximum output activity to minimize the inhibition impact of the inhibitory pathway already described (Garrido et al., 2013a). Nevertheless, this cerebellar gain controller reaches the adequate state through the learning process. This involves a time period in which the control action is not delivered properly which make the system prone to become unstable. The cerebellum, during this learning process, shall be able to supply enough control action to avoid these possible destabilization inconveniences. Furthermore, the feedback action in cerebellar motor control is indeed well accepted (Kawato and Gomi, 1992;Stroeve, 1997;Desmurget and Grafton, 2000;Kalveram et al., 2005) and there also exist neurophysiologic evidences suggesting that the primary motor cortex is involved in this feedback loop (Sergio et al., 2005). Concretely, there is a dense projection from primary motor cortex to the spinal cord, often directly onto motor neurons, and correlations between primary motor cortex activity and end-effector kinematics (Todorov, 2000). Hence, proprioceptive signals encoding for instance position error information (inputs) are put in relation with the corrective cerebellar output, thus leading one to believe that the IO-DCN connection might implement this loop.
When a message comes to the brain from body parts such as the hand, the brain dictates the body on how to respond such as instructing muscles in the hand to pull away from a hot stove. The nerves in one’s skin send a message of pain to the brain. In response, the brain sends a message back dictating the muscles in one’s hand to pull away from the source of pain. Sensory neurons are nerve cells that carry signals from outside of the body to the central nervous system. Neurons form nerve fibers that transmit impulses throughout the body. Neurons consists of three basic parts: the cell body, axon, and dendrites. The axon carries the nerve impulse along the cell. Sensory and motor neurons are insulated by a layer of myelin sheath, the myelin helps
Retrieved 14 May 2014, from http://www.teachpe.com/a_level_analysis/movement_analysis_webpage.html. Thibodeau, G., & Patton, K. (1993). "The Species of the World. " Chapter ten: Anatomy of the muscular system. In Anatomy and Physiology (1st ed., p. 252).
The nervous system includes the brain and spinal cord of the central nervous system and the ganglia of the peripheral nervous system. The functional unit of the nervous system is a neuron. It is estimated 100 billion neurons reside in the brain with some neurons making anywhere between 10,000 to 100,000 connections with other cells! A distinctive class of neurons, mirror neurons discharge both when the individual executes a motor action and when he/she observes another individual performing that same or similar action. These mirror neurons were discovered by neurophysiologists in the 1990s at the University of Parma, Italy. Using macaque monkeys, these researchers found that neurons of the rostral part of the inferior premotor cortex were activated both when the monkey made goal-directed hand movements (grasping, holding, & tearing) and when the monkey observed specific hand movements done by the experimenters (Pellegrino, et al., 1992). In a monkey’s inferior frontal and inferior parietal cortex, it is estimated that about 10% of neurons have “mirror” properties.
These tasks are accomplished through the mechnoreceptors of the three semicircular canals, the utricle and the saccule (3). Like the neighboring auditory system, each canal has hair cells that detect minute changes in fluid displacement, but unlike the auditory system, the utricle and the saccule send information to the brain regarding linear acceleration and head tilt. Shaking your head ënoí employs one of these canals. Likewise, there is a canal that detects head movement in the ëyesí position, and there is yet another semicircular canal that detects motion from moving your head from shoulder to shoulder (4).
Contrast the differences between force and torque. Use each term to describe a particular aspect of a muscle’s contraction relative to a joint. (6 pts)
Manto, M., Bower, J.M., Conforto, A.B., Delgado-Garcia, J.M., da Guarda, S.N., Gerwig, M., Habas, C., Hagura N., Ivry, R.B., Mariën, P., Molinari, M., Nairo, E., Nowak D.A., Oulad, B.T., Pelisson, D, Tesche, C.D., Tilikete, C., & Timman, D. (2012). Consensus Paper: Roles of the Cerebellum in Motor Control – The Diversity of Ideas on Cerebellar Involvement in Movement. Cerebellum, 11, 457-487.
2. Sketch what Lorenzo’s neurons most likely looked like after one year. Then sketch a healthy neuron.
This arc belongs to the autonomic nervous system (ANS). The ANS is the part of the peripheral nervous system that is responsible for controlling involuntary body functions. This system helps us maintain a steady heartbeat while we are sleeping, and anything else that is necessary to keep us alive during low levels of consciousness. This system affects the body functions that are not consciously managed, such as breathing, digestion, heart rate, pupillary dilation, and urination. However, there are some ANS actions that we are able to control with our mind to a certain extent, such as swallowing.