Once flow out restoring the negative potentialinside

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Once flow out, restoring the negative  potential.(Inside - ) 2. The excess sodium ions (Na+) flow  out of the neuron, and the escaped  potassium ions (K+) recovered 3. Absolute refractory period, the  membrane is not excitable and cannot  discharge another impulse.  1. The cell closes its sodium  channels, and positively  charged potassium ions  flow out through their  channels.. (outside K+) - All-or-none law : action potentials occur at a uniform and maximum intensity, or they do not  occur at all.  - Graded potentials : Changes in the negative resting potential that do not reach the -50 milli  volt action potential threshold. (GP can add up to trigger an action potential)  - Myelin Sheath : a whitish, fatty insulation layer derived from glial cells during development.  (mainly interrupted by the nodes of Ranvier, where myelin is either extremely thin or absent)  Normally Myelin Sheaths are found in the nervous systems of higher animals.  3. How Neurons Communicate: Synaptic Transmission - Synaptic space: a tiny gap between the axon terminal and the next neuron. 
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Neurotransmitter Neurotransmitters are the chemical substances that carry  messages across the synaptic space to other neurons,  muscles or glands. (Synthesis, storage, release, binding, and  deactivating)  Specialized Transmitter  System 1. Neuromodulators have a more widespread and  generalized influence on synaptic transmission.  2. Underproduction of Acetylcholine (Ach) is an important  factor of Alzheimer’s disease.  3. Endorphins a neurotransmitter controls the  pain/pleasure.  Synthesis The formation of transmitter molecules. The molecules are stored in synaptic vesicles, chambers  within the axon terminals.  Release When an action potential comes down the axon, these  vesicles move to the surface of the axon terminal and the  molecules are surface of the axon terminal and the  molecules are released into the fluid-filled space between  the axon of the presynaptic (sending) neuron and the  membrane of the postsynaptic (receiving) neuron.  binding When a transmitter molecule binds to a receptor site, a  chemical reaction occurs.  1) Excitatory transmitter : sodium channels to open  (Depolarization). Causes either graded potential or an  action potential (max) 2) Inhibitory neurotransmitter:  @positive potassium ions to flow out of the neuron @negative chloride ions from the exterior to flow into  it through chloride channels in the  membrane(increasing negative potential, making hard  to fire) Deactivation When neurotransmitter molecule binds to its receptor, it 
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continues to excite or inhibit the neuron until it is  deactivated.  1)
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