How Neurons Conduct Signals

– Neurons are nerve cells that transmit info throughout the body and are the foundation of the nervous system.
– In general, neurons have a cell body (soma), a dendrite, and an axon.
– Different neurons will have different perks to their structure (longer dendrites/axons, myelin sheath etc.)
– The dendrite is where information is received from the synapse
– The axon is where that signal is sent to another neuron.
– Neurons can have thousands of synapses with other neurons.

– When an axon wants to send info away from the cell body an action potential occurs.
– When a neuron is at rest, or not sending a signal, it is at resting potential.
– Resting potential is approximately -70 mV
– All action potentials are the same size.

– Resting potential is occurring because of the sodium potassium pump.
– The sodium ions are moving to the outside and it is positive, while some potassium ions move to the inside. Because there are a greater number of sodium ions outside than potassium, the electric potential occurs
– When a stimulus causes a neuron to come out of rest, the sodium gates of the membrane open, allowing the sodium on the outside to rush into the cell
– In order to get an action potential, the depolarization must reach a certain threshold level in order to fire the message. If not, it will not occur (“All or none” principle)
– ┬áNow the inside of the cell is positive and the outside is negative.
– Once the action potential reaches it’s peak, the sodium gates close, and the potassium gates open.
– The potassium goes out of the cell while the sodium stays inside. This is called repolarization.
– Once the potassium gates close, because there is more potassium on the outside than there is sodium on the inside, the potential drops lower than the resting potential for a moment.
– The sodium gates will open once again, letting the sodium go back inside, going back to the original resting potential.

– Although the messages being sent from neuron to neuron are chemical, the procedure sending these messages from dendrite to axon are electrical.
– Within each axon terminal, there are vesicles that contain neurotransmitters
– Each neurotransmitter sends a different kind of message to the connecting dendrite.
– When a signal comes through the presynaptic ending, the vesicles within the axon terminal go towards the presynaptic membrane, and release the neurotransmitters that were wanted.
– There is also mitochondria in the axon terminal, the powerhouse of the cell.
– These neurotransmitter diffuse through the synaptic cleft and into a receptor site
– This is the postsynaptic ending.
– Each receptor site is like a lock, and neurotransmitters are like the keys to those specific receptor sites.
– These chemical messages may either be excitatory or inhibitory.
– Excitatory means that it wants the message to be passed on
– Inhibitory means that it doesn’t want the message to be passed on and will prevent it from doing so.
– After use, these neurotransmitters are either destroyed or recycled back into the axon terminal.

2 thoughts on “How Neurons Conduct Signals

  1. The way it is written in point form makes it easy to read and great for note taking and review.

    The information you included covers a lot of what we have learned so I found this useful to read and help my memory.

    Wish: A visual component or something unique would be nice and helpful for memorization but not necessary obviously!

  2. I like how the information is in point form making it easier to digest
    I think this would be a good post for review because it covers the lesson very well
    Would probably be better if some pictures were included

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