Action potential and Synapse function


What is a neuron?

A neuron is a basic unit of the brain, it is a specialized cell designed to pass on information to other nerve cells, muscle cells, or gland cells. Most neurons have a cell body, an axon, dendrites and a Merlyn Sheath. Axons transfer and carry signals to other neurons and the dendrites receive these signals. And the cell body is the neuron’s life source. Some neurons also have a myelin sheath, the myelin sheath is a fatty substance which surrounds parts of the axon, forming an electrically insulating layer. The only neuron that has a myelin sheath is the sensory neuron and they main purpose is to improve the speed of the neural impulse along the axon.

What is action potential?

An action potential is the sending of electrical impulses which is how neurons communicate. This happens trough depolarization and repolarization. At resting potential, the axon is negatively charged inside at -70mV. And when depolarization happens parts of the axon open up to let in two sodium ions which changes the charge inside the axon to positive. But then repolarization happens and potassium ions leave the axon which makes it negative again. The process of depolarization and repolarization happens all through the axon which causes the charge to move down the neuron.

Synapse Function.

So, the purpose of the action potential is to move the charge down the neuron so now that we the action potential at the axon terminal is moves to the the receptor of the next neuron. Also, the Synapse has three parts: the synaptic gap, the presynaptic membrane, and postsynaptic membrane. So, when it reaches the axon terminal it links to the presynaptic membrane and that then releases pockets of chemicals which are called neurotransmitters. These are released into the synaptic gap. And the neurotransmitters then connect or bind onto the receptors of the second neuron which is connected to the dendrites. Once they are binded they trigger either an excitatory or inhibitory respond. This will determine if the receiving neuron will continue to send the action potential (excitatory) or stop sending the message (inhibitory).


How an action potential moves along the neuron fiber

It goes through the axon


Neuron Structure and job.

Dendrites– Conducts messages toward cell body

-receive information from other neurons and sensory receptors

Axon– Conducts message away from cell body

Cell body– The cells life support center

Myelin Sheath- Covers the axon of some neurons and helps speed neural impulses

Terminal branches of axon- Form junction

A nerve impulse is an electrochemical reaction called action potential

Motor and Sensory Neuron


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