BIO2A03-2011-L22 - Biology 2A03 2011 Lecture 22 Click to...

Info icon This preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
Click to edit Master subtitle style 4/13/11 Biology 2A03 - 2011 Lecture 22 Neurophysiology IV
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4/13/11 Absolute refractory Absolute refractory No 2nd AP possible regardless of stimulus In absolute refractory period most of the Na+ channels are open then inactivated and most of the K+ channels start to open In relative refractory more and more Na+ channels are able to be activated and many of the K+ channels start to slowly close Relative refractory Stronger than normal stimulus needed for AP
Image of page 2
4/13/11 Refractory period: important in information coding at the initial segment, because the further above threshold is the G.P., the greater the frequency, until the absolute refractory period is reached. At sensory receptors, the greater the intensity of the stimulus, the greater the G.P., and the greater the frequency, until adaptation occurs. Information is coded as the frequency of A.P.’s Increased stimulus duration Increased stimulus strength Suprathreshold stimuli Time between AP directly related to amplitude of GP Fig. 8- 18
Image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4/13/11 Adaptation - a property of all sensory receptors For any constantly applied stimulus, the frequency of A.P.s, and therefore the perception of intensity, gradually declines with time. Very complex - explained by electrochemical (e.g. channel closing), mechanical (e.g. gradual deformation of receptor structure), and sometimes synaptic events. Tonic receptors - adapt very slowly - generally associated with life-critical sensation - e.g. pain receptors, blood gas chemoreceptors.
Image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

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