Video Transcript
Starting with receiving a chemical
signal from another neuron, which of the following correctly outlines the sequence
of transmission of an electrical impulse through a neuron? Dendrites, axon, cell body, axon
terminals. Dendrites, cell body, axon, axon
terminal. Cell body, dendrites, axon, axon
terminal. Axon terminal, axon, cell body,
dendrites.
To answer this question, we need to
recall the anatomy of a neuron and how this anatomy helps transmit an electrical
impulse to another neuron. This is your typical neuron. And in green, we see the chemical
signals mentioned by the question. The dendrites are the part of the
neuron that receives these chemical signals sent by other neurons. A neuron typically has many
dendrites. A key way to identify the structure
is to look for the part of the neuron that most resembles tree branches. It is at the dendrites that the
incoming chemical signal is converted into an electrical impulse to be sent to the
cell body of the neuron for processing.
The cell body of a neuron is also
called the soma. Since each neuron can have many
dendrites receiving signals from other neurons, the cell body plays a very important
role in integrating all of these incoming signals. After integration and processing,
it is the cell body that determines if an outgoing signal will be generated and
transmitted to the axon. From the cell body, the electrical
impulse is transmitted to the axon. The axon is the long threadlike
portion of the neuron which conducts the electrical impulse to the axon terminals
located at the end of the axon. Therefore, the axon is considered
the main conducting unit of the neuron. This axon is unmyelinated. This means the axon is not covered
by a myelin sheath.
In some neurons, the myelin sheath
can surround parts of the axon and helps to increase the speed of the transmission
of the electrical impulse. As the electrical impulse reaches
the end of the axon, it is transmitted to the axon terminal. The axon terminal is where the
electrical impulse is converted back into a chemical signal to be sent across the
synapse to the next neuron. So the axon terminal is the site of
secretory communication for the neuron.
Now that we’ve reviewed the anatomy
of a neuron and how this anatomy helps to transmit the electrical impulse to the
next neuron, we can answer the question. The correct outline for the
sequence of transmission of an electrical impulse through a neuron is dendrites,
cell body, axon, axon terminal.
