Presentation is loading. Please wait.

Presentation is loading. Please wait.

Comparative Vertebrate Physiology Action potentials.

Similar presentations


Presentation on theme: "Comparative Vertebrate Physiology Action potentials."— Presentation transcript:

1 Comparative Vertebrate Physiology Action potentials

2 Neuron anatomy and signaling

3 Action potential Depolarization Repolarization Hyperpolarization

4 Action potential Phases Resting membrane potential Depolarization Repolarization Hyperpolarization

5 Nernst equation Measures equilibrium potential Depends on: absolute temperature valence ratio of concentration gradients

6 Nernst equation If [K]o = 0.01M and [K]I = 0.1M

7 Action potential Hodgkin and Huxley theory Resting membrane potential

8 Action potential Resting membrane potential

9 Action potential Hodgkin and Huxley theory Depolarization: rising phase Na + (5,000x)

10 Action potential Hodgkin and Huxley theory Repolarization : falling phase K + (10x)

11 Action potential Hodgkin and Huxley theory Hyperpolarization

12 Membrane permeability

13 Protein gates Types Chemical Occur between neurons Voltage Occur within neurons

14 Voltage gates

15 Refractory period Absolute Na + activation gate open Relative Na + activation gate closed

16 Channel toxins TTX (tetradotoxin) Japanese puffer fish decreases Na + conductance increases K + conductance

17 Channel toxins TEA (tetraethylammonium) Synthetic organic compound increases Na + conductance decreases K + conductance

18 Channel toxins

19 Threshold An all-or-none event

20 Threshold Factors effecting Magnitude Duration

21 Excitation curve

22 Impulse conduction

23 Schwann cell secrete myelin

24 Conduction velocity Mylenated: 15 - 40 msec -1 Unmylenated: 0.4 - 0.5 msec -1


Download ppt "Comparative Vertebrate Physiology Action potentials."

Similar presentations


Ads by Google