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lec5 nervous system, Glial Cells, action potential - Coggle Diagram
lec5 nervous system
Neurons
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3大特点：
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High metabolic rate, need many nutrients
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Multipolar ( motor neuron)
Bipolar (retina of eye)
unipolar (sensory neuron)
interneuron ( 在sensory & motor中间，最多）
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Glial Cells
Astrocytes
Neuronal support;
repair damage;
regulate neuronal communication;
maintain blood-brain barrier;
exchange neuron & capillaries
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Ependymal cells
In ventricles; lines cavities
produce cerebrospinal fluid;
Create, secrete , cushions organs
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action potential
Channels( diffuse ion, 远离+Ions)
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Potentials
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Action potential
很大的change voltage-gate. channel 通过 depolarize
-55。threshold all or nothing phenomena , 带正电ion冲进来
但太多正电ion, SO. CALLED. action potential in action .
repolarization: K out,
hyperpolarization: 当太多K溜出去，降回到-75 直到gate Closed
从depolarization 到repolarization—- refractory
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Separate to create potential,
potential release energy;
Resisting membrane potential
内部更多负电-70,因膜外-Na比膜内K更多，所以负电
polarized-膜代负电
Sodium-Potassium pump :more+outside neuron
electrochemical gradient: 为了消除差距，让ion 穿膜