What is the difference between synapse and axon

Membrane potential — The electrical potential across the neuron's cell membrane, which arises due to different distributions of positively and negatively charged ions within and outside of the cell.

The value inside of the cell is always stated relative to the outside: mV means the inside is 70 mV more negative than the outside which is given a value of 0 mV.

An action potential travels the length of the axon and causes release of neurotransmitter into the synapse. The action potential and consequent transmitter release allow the neuron to communicate with other neurons. Neurotransmitter — A chemical released from a neuron following an action potential. The neurotransmitter travels across the synapse to excite or inhibit the target neuron. Different types of neurons use different neurotransmitters and therefore have different effects on their targets.

Synapse — The junction between the axon of one neuron and the dendrite of another, through which the two neurons communicate. QBI newsletters Subscribe. Help QBI research Give now. For communication between neurons to occur, an electrical impulse must travel down an axon to the synaptic terminal. At the synaptic terminal the presynaptic ending , an electrical impulse will trigger the migration of vesicles the red dots in the figure to the left containing neurotransmitters toward the presynaptic membrane.

The vesicle membrane will fuse with the presynaptic membrane releasing the neurotransmitters into the synaptic cleft. Until recently, it was thought that a neuron produced and released only one type of neurotransmitter. This was called "Dale's Law. The neurotransmitter molecules then diffuse across the synaptic cleft where they can bind with receptor sites on the postsynaptic ending to influence the electrical response in the postsynaptic neuron. In the figure on the right, the postsynaptic ending is a dendrite axodendritic synapse , but synapses can occur on axons axoaxonic synapse and cell bodies axosomatic synapse.

Psychol Rev. Your Privacy Rights. To change or withdraw your consent choices for VerywellMind. At any time, you can update your settings through the "EU Privacy" link at the bottom of any page. These choices will be signaled globally to our partners and will not affect browsing data. We and our partners process data to: Actively scan device characteristics for identification. I Accept Show Purposes. Soma The soma, or cell body, is where the signals from the dendrites are joined and passed on.

Axon Hillock The axon hillock is located at the end of the soma and controls the firing of the neuron. Characteristics Acts as something of a manager, summing the total inhibitory Possesses an internal polarization of approximately mV in normal resting state When a signal is received by the cell, it causes sodium ions to enter the cell and reduce the polarization.

Axon The axon is the elongated fiber that extends from the cell body to the terminal endings and transmits the neural signal. Characteristics Most neurons have only one axon Transmit information away from the cell body May or may not have a myelin covering Range dramatically in size, from 0. Terminal Buttons and Synapses The terminal buttons are located at the end of the neuron and are responsible for sending the signal on to other neurons.

Characteristics Contain vesicles holding the neurotransmitters Convert the electrical impulses into chemical signals Cross the synapse where they are received by other nerve cells Responsible for the reuptake of any excessive neurotransmitters released during this process A Word From Verywell Neurons serve as basic building blocks of the nervous system and are responsible for communicating messages throughout the body. Was this page helpful?

Thanks for your feedback! Sign Up. What are your concerns? Verywell Mind uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Related Articles. What Is the Somatic Nervous System? Neurotransmitters fall into four classes based on their chemical makeup.

Acetylcholine ACh is a small molecule formed from acetate and choline. It is in a class by itself. Acetylcholine is the sole neurotransmitter used at the neuromuscular junction and is also the neurotransmitters used by the parasympathetic nervous system.

Some amino acids act as neurotransmitters. Glutamate glutamic acid and aspartate are excitatory neurotransmitters found in the brain and spinal cord, respectively. Biogenic amines monoamines are formed from amino acids from which the carboxyl terminus is removed. Three of the biogenic amines, called the catecholamines, are grouped together as they are all derived from the same amino acid, L-tyrosine.

The catecholamines include: norepinephrine noradrenalin , epinephrine adrenalin and dopamine dopamine can also be made from phenylalanine. Norepinephrine NE is the neurotransmitter of the sympathetic nervous system your fight or flight response. Epinephrine E has similar effects to NE, but is less abundant. Dopamine is best known for its role in motor inhibition.

Loss of dopamine producing neurons in Parkinson disease leads to dyskinesias movement disorders. Catecholamines bind to adrenergic receptors. Other biogenic amines include serotonin and histamine. The structures of the biogenic amine neurotransmitters. Neuropeptides are small proteins that function as neurotransmitters.

They are the largest neurotransmitters and can range from just a couple of amino acids to as many as Examples of neuropeptide neurotransmitters. Privacy Policy. Skip to main content.

Search for:. Synapses Introduction to Synapses Several neurons are generally needed to transmit a signal from one place in the body to another. Structure of a chemical synapse. CC BY. The structure of acetylcholine. Licenses and Attributions.