NATS 1860 Week 2 Notes

Importance of na channels remove na outside neuron no

This preview shows page 15 - 23 out of 26 pages.

Importance of Na + Channels • Remove Na + outside neuron: no spikes • Block Na + channels chemically: no spikes • TTX in Japanese puffer fish • TTX: nerve toxin that blocks Na + channels • Sushi delicacy: a little & lips tingle • Too much & your brain stops & you die Monday, January 14, 2013
Image of page 15

Subscribe to view the full document.

Spike Conduction Demo (book Fig. 3.3) Axon depolarizes in front & hyperpolarizes behind Speed important in long axons Squid: large diameter (1-2 mm) goes faster (1 m/ sec) Human axons (2 microns in diameter) Insulation (myelin) with gaps (Nodes of Ranvier) Spike jumps from gap to gap (100 m/sec) Damage to myelin: multiple sclerosis Monday, January 14, 2013
Image of page 16
Myelin Node of Ranvier Myelin Node of Ranvier Axon Spike •Node behind spike is refractory (K+ exits) Spike Conduction Spike jumps from node to node K + channels open behind spike Can ʼ t go backwards Monday, January 14, 2013
Image of page 17

Subscribe to view the full document.

Synapses Book Fig. 3.8 Monday, January 14, 2013
Image of page 18
Synapses Terminals of axons Terminate on dendrites or somas of other neurons Contain vessicles of neurotransmitter molecules Book Fig. 3.10 Monday, January 14, 2013
Image of page 19

Subscribe to view the full document.

Synaptic Transmission Monday, January 14, 2013
Image of page 20
Synaptic Transmission Spike arrives & depolarizes axon terminal • Ca ++ ion channels open & Ca ++ enters terminal Causes vessicles to release neurotransmitter Neurotransmitter binds to postsynaptic neuron receptor Causes ion channel to open Ions flow into or out of postsynaptic neuron Changes postsynaptic neuron potential Monday, January 14, 2013
Image of page 21

Subscribe to view the full document.

Excitatory Synapses Glutamate (GLU) is neurotransmitter Opens Na + ion channels in postsynaptic neuron • Na + ions enter & depolarize neuron Excitatory: shifts neuron closer to threshold E xcitatory P ost- S ynaptic P otential = EPSP Ion channels shut after about 10 ms Spikes not generated at synapse Monday, January 14, 2013
Image of page 22
Image of page 23
  • Spring '08
  • AGARD/LANDZBY
  • axon hillock, Monday

{[ snackBarMessage ]}

Get FREE access by uploading your study materials

Upload your study materials now and get free access to over 25 million documents.

Upload now for FREE access Or pay now for instant access
Christopher Reinemann
"Before using Course Hero my grade was at 78%. By the end of the semester my grade was at 90%. I could not have done it without all the class material I found."
— Christopher R., University of Rhode Island '15, Course Hero Intern

Ask a question for free

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern