What Is Neuromuscular Junction

Describe the process of synaptic transmission. Include in this description the differences between excitatory and inhibitory transmitters.Sypnaptic transmission is the method in which obe nerve cell communicate to another nerve cell .The communication between nerve cells is done by branching or processing the nerve cell singnals that are passed by t have e nerve cell body or "soma", dentristes, and electrical axon or chemical signals

The structure of neuromuscular junction consists of a neuron and skeletal muscle cell. The motor neurons, which arise from the spinal cord, supply the skeletal muscle fibers. The neuromuscular junction is un-myelin nerve with a bulb shape at the endings that contract the muscle fiber. The schwann cells form a covering over the postsynaptic membrane and nerve membrane of the fiber that is located under the terminal and is categorized as a post-junction folds. The area between the folds and the bulbs create the synaptic cleft. This consists of proteins and proteoglycans. The enzyme acetylcholinesterase; exist only at high levels in the synaptic basal lamina (UMN,

As an action potential travels down the axon of the presynaptic neuron, the action potential reaches the axon terminal synaptic vesicles which migrate toward the synapse. They then release neurotransmitters into the synaptic cleft. The neurotransmitters travel through the synaptic cleft and bind to ligand-gated ion channels on the postsynaptic neuron membrane. The channels open and allow chemicals to enter the cell (i.e. sodium). Then positively charged sodium enters the cell and causes the cell to depolarize. The depolarization spreads down the axon and an action potential is generated. The process then starts over at the axon terminals.

The Synapse- The synapse is a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron.

As the message arrives at the end of the nerves, the message is transmitted to the muscles. Before the message is transmitted to the muscles it has to pass the space between the end of the nerve and the muscle, and that space is called neuromuscular junction. The message is transmitted from the brain to the end of the nerve and from the nerve to the neuromuscular junction, and when the message arrives the chemical called neurotransmitters are released.

The neuromuscular junction constitutes of three regions consisting of the presynaptic cell, the synaptic cleft, and the post synaptic cell.

This action potential signals vesicles containing neurotransmitters to be released into the synaptic cleft, or space between two neurons containing extracellular fluid. Neurotransmitters bind to sites found on ion channels of the adjacent neuron, due to the impermeability of neuron membranes to ions, neurotransmitters are necessary for the movement of action potentials between neurons. The chemical synapse or the transfer of ions between the axon of one neuron to the dendrite of another allows for the chemical signal to be conveyed through a neural network to achieve an end result, such as skeletal movement, sight, and touch. Electrical synapses are also used alongside chemical synapses to transfer the chemical message to the appropriate recipient. These synapses are found between two dendrites, they communicate the changes in charge through gap junctions which allow for the passive diffusion of ions through the neurons connected, this results in a response from all neurons that receive the action potential (Stufflebeam, 2008). The nervous system affected by Hirschsprung’s disease is specifically the enteric nervous system it communicates to the central nervous system through both the parasympathetic and sympathetic systems, which is a denomination of the peripheral system. The peripheral

The main components of the synapses are as follows: The Axon terminal, found at the end of the Axon, passes neurotransmitters to other neurons via synaptic transmission. Synaptic Vesicles contain neurotransmitters within the Axon. Neurotransmitters themselves are chemical messengers that travel through the neurons and activate receptors on the receiving cell. The neurotransmitters are diffused through the synaptic cleft—a region between the two neurons and gap the neurotransmitter needs to cross to make it to the receiving cell. Said receiving cell is what receives the neurotransmitters and starts the process over again. The receptors on the cell are structures that receive the neurotransmitters and

As soon as the electrical signal reaches the end of the axon, mechanism of chemical alteration initiates. First, calcium ion spurt into the axon terminal, leading to the release of neurotransmitters “molecules released neurons which carries information to the adjacent cell”. Next, inside the axon terminal, neurotransmitter molecules are stored inside a membrane sac called vesicle. Finally, the neurotransmitter molecule is then discharged in synapse space to be delivered to post synaptic neuron.

The processes involved in skeletal muscle contraction begin with each individual muscle cell being innervated by a single motor neuron from the brainstem or spinal cord. Individual skeletal muscle cells are electrically insulated from each other, and so each must be individually stimulated. However, the motor neuron branches out at its terminal end, so a single neuron can reach many individual muscle cells. The ends of the motor neuron are known as ‘terminal boutons’ (Stanfield 2013, p.315) or ‘axon terminals’ (Tortora and Derrickson 2009, p.315), and they form one half of a synapse called a ‘neuromuscular junction’. Opposite the axon terminal, across the synapse, is an area of the muscle cell called the ‘motor end plate’, an area of folded

The benefits of physical exercise for humans are known for many years and physical training can interfere positively in the up regulation and protein expression of several molecules and growth factors. Firstly, the physical exercise can alter the expression of Glial cell line-derived neurotropic factor (GDNF) differently in slow and fast muscle fibers, and thereby affect peripheral motor neurons. Wehrwein, Roskelley & Spitsbergen (2011) showed that 4 weeks of walking exercise on a treadmill increased GDNF content in soleus, gastrocnemius and pectoralis major muscles, while limb immobilization generated opposite effect. In addition, increased expression of Neurotrophin

Most neurons do not make direct connections with surrounding neurons, signals (molecules) must make the transition from the presynaptic (upstream) neuron to the postsynaptic (downstream) neuron. This transition space is called the synaptic cleft. The exchange of information from the pre- to postsynaptic neuron is called a synapse.

An action potential will be propagated to the axon terminal of the motor neuron, when it arrives, it will trigger an influx of calcium ions, which will then trigger the exocytosis of acetylcholine to the neuromuscular junction, via the terminal vesicles. Once the acetylcholine has exited the membrane of the postsynaptic cell(neuron), it will bind to the receptors on the motor end plates of the muscles, this will trigger the opening of voltage-gated sodium channels, the sodium will depolarize the membrane of the postsynaptic membrane and then the action potential will be propagated. When the action potential arrives at the sarcoplasmic reticulum of the muscle, it will trigger a release of calcium; which is a very key factor in muscular contractions. The contraction cycle starts when calcium ions bind to troponin, this causes tropomyosin to change its conformation and by doing so it exposes the active sites on the actin. After this cross-bridge formation occurs, and the thick filament starts to pull on the thin filament.

Synaptic connections are signals that allow neurons (nerve cells) to connect and pass from one to the other, within the cerebral cortex of the brain. It allows the baby to develop color vision, pincer grasp, or a strong attachments with parents.

Nerve conduction studies are often utilized by clinician to diagnose patients suffering neuromuscular diseases that cannot be determined by neurological examination alone. Nerve conduction velocity (NCV) measures the speed of conduction of an electrical impulse that travels through a nerve. It is an expression of the physiological state of the nerve itself. In order to determine the NCV of the Ulnar nerve, a stimulator is initially used to depolarize the nerve. A small electrical stimulus is applied to the nerve. Before the electrical stimulation, the membrane is said to be at resting potential of -70mv. If the electrical impulses is greater then the threshold potential (-55mv), then the electrical stimulus will causes the opening of the Na+ channel, permitting the influx of Na+ into the cell membrane, thus causing further depolarization of the cell membrane. The K+ channels open thereafter and leads to efflux of K+ and restoration of the resting potential of the membrane. The rapid change in the charge of the nerve is called an action potential (AP). In the Ulnar nerve, the depolarization associated with the AP travels rapidly, with little attenuation from one node of Ranvier to the next. This known as Saltatory conduction. As the AP travels down the nerve cell, it causes the release of Acetyl coenzyme A (acetyl-CoA) into the synapse. As acetyl-CoA binds to the nicotinic acetylcholine, it causes an AP in the muscle cell. AP propagates down the T tubules to the sarcoplasmic