There are 3 different types of neurons, these include the sensory, motor and interneuron. These neurons contain these structures;

  1. The soma is the cell body of the neuron
  2. The axon is the long projection that conducts electrical impulses away from the soma.
  3. The dendrites conduct electrical signals towards the soma.
  4. The synapses transfer electrical signals from one neuron to another.
  5. Terminal buttons- form junctions with other cells

 

action potential-

The action potential of a neuron is a fast electrical charge that follows down the neuron. The positive flow of ions in and out of the neuron causes this whole process. It has a very specific trigger value and if that number is not reached it will not trigger the action potential no matter how close it gets. The action potential follows a step guided process. It starts at Resting Potential, this stage,  the neuron is ready to be used and send out a signal. When the neuron is in Resting Potential there are more positive ions on the outside and the inside has a “net” negative charge. Next, depolarization begins, while the neuron is being used,  the channels in the membrane open to allow NA+ ions to enter the axon. The next step is repolarization, this is the recharge period. During Repolarization the channels open to allow K+ ions to exit the axon, this causes the next segment to depolarize. Finally, the refractory period, Flow of Depolarization this causes the K+ and NA+ to switch around to then prepare for the upcoming wave of AP. The Flow of Depolarization gathers to neuron to its original state so it can repeat the process.

The Insulated Neuron:

  • Glial Cells
  • Cells that provide structural, nutritional, and other support for the neuron
  • Schwann cell
  • Wraps around axon
  • Myelin insulates axon
  • Faster signal conduction
  • Nodes of Ranvier = spaces between
    Schwann cells
  • Action Potential jumps from Node to Node along the axon

When the nerve impulse reaches the end of the axon and makes up to the correct threshold, the axon then begins to release neurotransmitters. There are different kinds of neurotransmitters, such as serotonin, Dopamine, Acetylcholine, Gamma-aminobutyric acid and Glutamate. Neurotransmitters travel across the synapse gap between the axon and the dendrite of the receiver neuron. The neurotransmitters calm through the gap & bind to receptors on receiving neurons. Neurotransmitters bind to the membrane of the dendrite. The binding allows the nerve impulse to travel through the receiving neuron. The receiving neuron decides whether or not to send the signal to the next neuron by taking the sum of the signal. If there are more excitatory’s than the inhibitory signals then it will continue down and send the next signal; however, if there are more inhibitors then excitatory then the neurons will not send the next signal and it will not continue down. The reason for this process is because we have a lot of signals flowing through our body at one time, this process helps organize and quickly complete them because the nerve cells are connected to so many nerve cells.