Class Notes (810,868)
Canada (494,338)
Psychology (4,979)
PSYCH 2AP3 (472)


5 Pages
Unlock Document

McMaster University
Richard B Day

Neuroscience ● The brain is made up of 100 billion neurons and a typical cortical neuron can have between 1 and 10,000 connections with other neurons ● Rene Descartes: mind seen as separate entity existing outside of our biology yet in control of actions and thoughts ○ Physical brain serves as connection between mind and body ● Neurons: communication cells ○ Two zones ■ Receptive zone: receive signals from other neurons ● Made up of dendrites branching out from the cell body ● The cell body contains most of the vital organelles which keep it functioning ● Dendrites reach out to other neurons and receive signals to be relayed through a dendritic branch to the cell body – from there they can go down to the axon ■ Transmission zone: passes on signals to other cells ● Made up of the axon and terminal boutons ● Axon: a long fibre that varies in length ● Terminal Boutons: cluster of branches at the end of the axon ○ Reach out and make connections with receptive zone of nearby neurons to transmit the signal further ● Glial cells: provide structural support, nourishment and insulation needed by the neurons ○ Work together with the neurons, resting in a bath of ions, chemicals and blood casculature ● Resting Potential : baseline imbalance of -70mv relative to the outside of the cell ○ Potassium ions inside(+) ○ Sodium ions outside(+) ○ Chloride outside(-) ○ Protein molecules outside (-) ○ Diffusion: the tendency for molecules to distribute themselves evenly in a medium ○ Electrostatic Force: the repulsion between ions with the same charge ○ Leaky Potassium Channel: always open, allowing positively charged potassium to pass through the cell membrane out of the neuron ○ Voltage Gated Channel: closed in the resting state ● The Threshold: fluctuating around -50mv ● The Action Potential: ○ Sodium channels along cell open ○ Force of diffusion causes positive sodium ions to begin rushing into neuron which causes the charge on outside of cell to become more positive relative to outside ○ Electrostatic force begins to push some potassium ions out of the cell through leaky potassium channels ○ Net effect is to increase the positive charge building up inside the cell to the point where voltage gated potassium channels open which allow positive potassium ions to rush out of cell ○ After reaching peak of 40mv inside of cell, sodium channels close ○ Sodium stops entering the cell but potassium still rushes out ○ Inside of cell begins losing positive charge and continues to fall and overshoots resting potential ○ Voltage gated potassium channels close, and completes rush of ions ○ Cell slowly returns to -70mv and a short refractory period occurs where the neuron cannot fire another action until it recovers ○ Sodium Potassium Pump: removes sodium from cell and replaces with potassium ■ Expels 3 sodium ions from inside cell and replaces with 2 potassiums ■ Moves slowly and utilizes extensive energy ○ Begins in receptive zone of the neuron, cascades along axon toward terminal boutons ○ Myelin ■ Special cells are the oligodendrocytes in the central nervous system ■ Schwann cells in the peripheral nervous system ■ Insulating layer allows action potential to travel down the axon much faster ■ Saltatory Conduction: action potential jumps across a myelin sheath
More Less

Related notes for PSYCH 2AP3

Log In


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


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.