The Axon: The Action Potential

Describe the anatomy of the neuron and the ways that neurons communicate with each other.

As well as these there are also the axon of the cell which is covered in myelin sheaths which carried information away from the cell body and hands the action potentials, these are small short bursts of change in the electrical charge of the axon membrane through openings of ion channels, off to the following neurons dendrites through terminal buttons at the end of the axons. Whenever an action potential is passed through these terminal buttons it releases a chemicals that pass on the action potential on to the next neuron through the terminal button and dendrite connection. The chemicals that are

To send a message, a neuron will send a ripple of electrical energy down its axon. This ripple is called "action potential." The way it works is by changing the chemical makeup of the axon's negatively charged interior. Positively charged sodium ions move into the cell and negatively charged potassium ions move out, then the ions move to their original positions. This produces a wave of positively charged

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 cell body comprises of the nucleus and other organelles (Ward, 2010). The nucleus contains the genetic code, and this is involved with protein synthesis (He, 2013). The dendrites receive information from other neurons which are located in a close proximity (Kalat, 1995). The terminal of an axon compresses into a disc-shaped structure (Gross, 2010). This is where chemical signals also known as a neurotransmitter permit interaction amongst neurons, by means of a minute gap named a synapse (Martin, Carlson & Buskit, 2013). Both neurons which form the synapse are referred to as a presynaptic synapse (prior to the synapse) and postsynaptic (after the synapse), reflecting the direction of information flow (from axon to dendrite), (He, 2013).

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 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

A synapse is a link where neurons communicate with other cells across narrow gaps using neurotransmitters or pulses (I learned this in my biology course last semester).

Once in the synapses, the impulses triggers the release of chemical messages called neurotransmitters; which then bind to receptors on the receiving cell as the transmission of the impulse repeated again. The message or impulse continues traveling from one neuron to the next throughout the body until it reaches its destination as it relays a signal. All of this activity happens in less than a split second and without conscious thought. At the end of this process, the brain has the task of interpreting the message and making the decision as to what to do with this new information. (Carlson, 2011.Pg.45-52)

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.

Peripheral axons from auditory spiral ganglion neurons project to the organ of Corti and synapse with both inner and outer hair cells prior to the onset of hearing. The developmental processes that determine axon outgrowth are largely unknown, though it is thought that a combination of axon guidance molecules and neurotrophic factors determine the fate of the projections. Here, we use immunofluorescence to show that the P2X3 receptor is expressed in both spiral ganglion neurons and hair cells during cochlear development. Furthermore, we demonstrate that P2X3 expression is nearly ubiquitous among spiral ganglion neurons at E16.5. These results support previous work on the spatial expression of P2X3 during development and serve as a foundation for future examination of the developmental function of P2X3.

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.

Nerve impulses are received by the dendrites, travel down the branches of the dendrites to the nerve cell body, and are carried along the axon. When the impulse reaches the branches at the end of the axon, it is transmitted to the next neuron. Impulses continue to be carried in this way until they reach their final destination. The final destination depends on what type of neurons they are.

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.

Axons are sensitive and their respond depend on the local environment. When the tectum is removed, retinal axons grow toward the missing tissue, demonstrating that optic axons utilize these neighbourhood signals as opposed to a long-run diffusible attractant from the tectum as they grow along the optic tract (Taylor, 1990). In the event of a small piece of the optic tract neuroepithelium is turned 90° preceding the axons enter it, then they become misoriented when they enter the pivoted transplant (Harris, 1989) and correct their course of growth once they exit. These results confirm that the neuroepithelium contains local information to which growing axons respond and that they are not simply following gradients of attractants released by their targets (Sanes et al., 2012). Growth cone filopodia are long, motile, and covered with receptors, also have a very high surface to volume ratio, which can help convert membrane signals into large changes in intracellular messengers such as calcium. Filopodia can show localized transient elevations of intracellular calcium and these transients reduce filopodial motility (Sanes et al., 2012). Calcium transients can be directly artificially activated in growth cone filopodia by loading neurons with a calcium caging agent that releases calcium upon stimulation with a pulse of light (Gomez et al., 2001). Experiments in which calcium is uncaged on one side of a growth cone generally cause the growth cone to turn toward the side that has