CAS BI 107 Lecture 16: Neurobiology of the Synapse
30 Oct 2018
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Document Summary
Two systems are used for internal communication: cns - pns: specialized cells called neurons (transmit nerve signals) (electrical signals, endocrine s: pineal, pituitary, thyroid, thymus, adrenal glands, pancreas, ovaries, testes. Myelin sheath: many layers of phospholipids, deposited by schwann cells as they grow, 20 layers on top of axon. Node of ranvier ( not in drawing it in the dip between myelin sheaths): speed up the ap since it can jump that is called saltatory conduction. Na is largely prevented from moving down its () gradient: protein inside the axon are - re charged (organic onions) Action potential: depolarization --- k channels close, na open na rush into aron 30mv. 2: repolarization--- na close, k open, k leaves the neiron down () -70mv. Propagation: happens because the ion movements that depolarize 1 part of a neuron trigger depd. in the neighbouring part of the neuron. Local currents: due to movements of na ions inside and outside of neuron.
