Class Notes (784,774)
Canada (481,351)
Psychology (4,819)
PSYCH 3A03 (56)
Paul Faure (56)
Lecture

Afferent and Efferent Physiology.docx
Afferent and Efferent Physiology.docx

3 Pages
135 Views
Unlock Document

School
McMaster University
Department
Psychology
Course
PSYCH 3A03
Professor
Paul Faure
Semester
Fall

Description
October 22 , 2013 PSYCH 3A03: Audition Afferent and Efferent Physiology Inner Haircell Connection to CNS - IHC synaptically connected to all type I spiral ganglion neurons forming a radial afferent system going to cochlear nucleus - Lateral efferent system arises from small neurons in ipsilateral lateral superior olivary (LSO) complex and brings feedback control to the IHC/type I afferent synapse Outer Haircell Connection to CNS - OHC synaptically connected to a few small endings of type II spiral ganglion neurons forming the spiral afferent system going to cochlear nucleus - Medial efferent system arises form large neurons from the both the ipsilateral and contralateral medial superior olivary (MSO )complex Radial versus Spiral Nerve Fibers - Type I (large, myelinated) spiral ganglion neurons have a single synaptic ending radially connected to IHC Electric Potentials - The motions and interactions of various cochlear structures generate electric potentials - Cochlear electric potentials tell us how the ear works - An electrical potential is potential energy per unit of charge associated with a static (time-invariant) electric field - An electric potential is established whenever there is a concentration difference in charged ions between 2 regions (e.g. across a cell membrane) - Electric potentials are present in all cells that regulate the ionic content of their cytoplasm with respect to the ionic content of the extracellular environment Cells have a Resting Electric Potential - Passive channels - Ion channels open or close when there is a potential Electrodes Measure Electric Potentials - Electrical potentials are measured with electrodes  Anything along which ions can flow  Wire electrodes (e.g. tungsten, silver)  Glass electrodes (e.g. borosilicate pulled to fine tip) - We use electrodes to measure the electric potential difference between 2 sites - Therefore 2 electrodes are necessary: 1. Recording electrode 2. Reference electrode - Recording electrode measures the electric potential difference at the site of its penetration relative to the site where the reference electrode is placed Measuring Electric Potentials - Inside of the axon is negatively charged - When the two electrode are no the outside there is a 0 potential difference - When one electrode is pushed in the cell membrane there is a negative potential with respect to the outside of the cell - DC potential (constant) - Around -70mV Resting Potential is Based on all Ions - Intracellular: more potassium, less sodium - Extracellular: more sodium than potassium - If a sodium channel opens, sodium flows down its chemical gradient into the cell to the point where the charge begins to oppose the charge gradient Measuring Electric Potentials - -70mV resting potential AC vs. DC Electric
More Less

Related notes for PSYCH 3A03

Log In


OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


OR

By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.

Submit