midterm 1 - Central nervous system- brain and spine-...

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Central nervous system- brain and spine- integration and analysis of motor and sensory neurons Peripheral nervous system- para/sympathetic, motor nerves, sensory nerves Cervical-8, thoracic- 12, lumbar- 5, sacral-5, coccygeal-5 Reflex circuit- sensory neuron activated by hammer bifurcates in spine one to excite motor neuron to extensor and one to interneuron to inhibit motor neuron to flexor Sensory neuron increase fire rate when hammer hits, excitatory motor neuron and inter neuron increase fire rate, and inhibitory motor neuron has no fire rate Transporters- against concentration gradient, creates an ion concentration gradient Channel- with concentration gradient Eion= 58/z log([ion]out/[ion]in) ATPase pumps- 3Na+/2K+, and Ca++/H+ Exchangers/transporters- Na/Ca, Na/K/Cl, K/Cl, Na/H If membrane does not reach threshold then potential decreases away from spot of stimulation back to resting potential Na+ time dependent channel Na+ are fast positive cycle while K+ is slow and negative in APs If membrane does reach threshold then it propagates with same amp with finite velocity along membrane Synapses can generate a graded subthreshold potential and can be integrated into a graded potential Electrical synapse- gap junction- ion transfer by connexon between pre/post-synaptic membranes- can flow back- in opposite direction Chemical synapses- AP depolarizes pre terminal and opens voltage gated Ca++ allows vesicles to fuse with membrane and release NTs into synaptic cleft, and bind to receptors to open channel Electrical synapse can synchronize activity of functionally related neurons Incrase in Ca++ in pre terminal necessary to release NTs MEPPs because of quantal release because of vesicles
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This note was uploaded on 10/14/2010 for the course BIOLOGY bipn 142 taught by Professor Aaron during the Spring '10 term at UCSD.

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midterm 1 - Central nervous system- brain and spine-...

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