Nervous System

Created March 2020, Offline version here
Video by Paul Anderson, also on his website Bozeman Science.

    The base unit of the nervous system is the , which can send messages, called . The resting membrane potential of a neuron is , which is established by the , which pumps out of the cell and into the cell. When a neuron encounters a stimulus, channels open, causing the ion to diffuse down its concentration gradient, the voltage of the cell. If the membrane potential rises above the potential of , additional channels will open in response to the change in potential, and the membrane potential will continue to rise. Once the membrane potential is positive, the channels will close, halting diffusion of the ion. After this, channels, sensitive to membrane potential, open to allow diffusion of the ion down its concentration gradient. This brings more the cell, the membrane potential. The is responsible for reestablishing resting membrane potential. In order to propagate an action potential to a downstream neuron, are released by the neuron and diffuse across the to bind to ion channels on the neuron. neurotransmitters increase the potential of the postsynaptic neuron and neurotransmitters the potential of the postsynaptic neuron. Whether or not the postsynaptic neuron reaches the potential determines whether or not the message from the presynaptic neuron is propagated.