Neuron Worksheet

Part I: In the text boxes provided, identify the structures of a basic neuron.

Box 1- Soma

Box 2- Dendrites

Box 3- Axon Hillock

Box 4- Nucleus

Box 5- Axon

Box 6- Node of Ranvier

Box 7- Myelin Sheath

Box 8- Terminal Buttons

 Part II: In the space provided, explain the process a neuron undergoes when going from a resting potential to an action potential to the release of its neurotransmitters.

When a neuron is inactive or the neuron is unstimulated with an electric charge of around negative 70 millivolts this is called the resting potential of the neuron (Carlson, 2013). Potential is the term that is used when the neuron is resting and has a negative charge or the term can be used in action potential where the neuron has a positive charge. At a resting potential the neuron will have a charge that is similar to what is outside the neuron and the ions that are present try to remain balanced on both sides of the neuron’s membrane (Carlson, 2013). This can be a difficult thing for the neuron to manage as some ions like chloride and sodium have a hard time passing into the membrane while others like potassium are able to free and easily pass through the cell. When the neuron is at rest there is more sodium outside it then inside it and more potassium on the inside than there is on the outside. When the neuron becomes activated or stimulated the neuron charges in order to reach the neural threshold which causes the neuron to fire, or the membrane of the neuron changes permeability (Carlson, 2013). The neuron is then able to change the electric charge from negative to positive running along the entire membrane. Carlson (2013), states that the stimulation must reach the neuron’s neural threshold or the neuron is unable to fire. At this time the channels open allowing sodium ions to freely flood into the neuron depolarizing the neuron and creating the needed action potential, an electrical impulse which will run down the length of an axon until it reaches a synapse. This is the point between two neurons where data is exchanged among them. Carlson (2013), states that the action potential causes a transfer of data or information from the axon of one neuron to the other neuron’s dendrites through the use of neurotransmitter chemicals. The dendrites of the neurons do not physically touch but rather have a small space in which to pass chemical messages back and forth from. The action potential of the neuro causes the neurotransmitters to release across this small space and bond or link with molecules at receptor sites on the opposite neuron. The bonding that happens causes the next neuron to change its potential from resting making the membrane permeable and allowing the flow of ions to take place ether decreasing or increasing the probability that the neural impulse will occur (Carlson, 2013). This marks the cycle of the change from resting to action potential in the next neuron while the first one begins to return to resting again.

Reference:

Carlson, N. R. (2013). Physiology of behavior. (11th ed.). Boston, MA: Allyn & Bacon.