Textbook Notes (363,143)
Canada (158,220)
Psychology (1,309)
PSYCH 1XX3 (270)
Joe Kim (243)
Chapter 5

PSYCH 1XX3 Chapter 5: Module 5- Neuroscience 1

6 Pages
Unlock Document

McMaster University
Joe Kim

Module 5- Neuroscience 1 - The brain is made up of approximately 100 billion neurons - A typical cortical neuron can have between 1 and 10,000 connections - Rene Descartes o The mind was seen as a separating entity existing outside the biology o The physical brain was thought to serve a connection between the mind and the body The Neuron - The cells of your body are specialized for different functions o Secrete hormones o Protective barriers o Contract and form the muscles o Neurons, specialized for communication - The 100 billion neurons in the brains are organized into signaling pathways to communicate via synaptic transmission - Unique structure makes is ideal for transmission - Neuron contains two distinctive zones o Receptive zone: designed to receive signals from other neurons, composed of dendrites o Transmission zone: pass signals on to other cells, made up of axon and terminal ends - The receptive zone of the neuron begins with the cell body - Cell body contains most of the vital organelles which keep the cell functioning - Branching from the cell body re a number of projections called dendrites, the dendrites reach out to other neurons and receive signals to be relayed through the dendritic branch to the cell body, some will go down to the axon - Once a neuron receives a signal it is passed down a long fiber called the axon o Can vary in length - At the end of the axon approaching the transmission zone of the neuron is a cluster of branches called terminal boutons or terminal ends - The terminal boutons reach out and make connections with receptive zone of nearby neurons to transmit the signal further - Glial cells provide structural support, nourishment and insulation to neurons The Action Potential - The cell membrane is selectively permeable - Preferentially allowing different ions to pass through with various levels of ease - Cell membrane contains a number of protein channels which act as passageways for ions to pass through o Potassium channel o Sodium channel - Each ion is either positively or negatively charged - The inside of a typical neuron start off with a -70mv relative to the outside of the cell - The baseline imbalance is the resting potential of the neuron - Two types of potassium channels o Leaky channel, like a tap that is always open o Voltage gated - Chloride ions are also mobile - The electrostatic force for the negatively charged protein molecules inside the cell keeps the negatively charged chloride ions primarily on the outside of the cell - Voltage gated sodium channels are closed in the resting state of the neuron and so the positively charged sodium ions flow into the cell in only very low concentrations - Most of the sodium ions remain resting on the outside of the cell and the flow od sodium is far less important to the resting state of the neuron than potassium - The forces governing the distribution of ions are not rigidly stuck in place, it is constantly fluctuating, around ~-70mv - Throughout the action potential and after the sodium potassium pump plays a role in removing sodium from the cell and replacing potassium - Expels three sodium and replaces it with two potassium - Important in maintaining the ion balance of the neuron and recovering from action potential - The action potential begins in the receptive zone of the neuron, where the cell body connects to the axon - The rapid changes that occur here cause changes in the ion concentrations surrounding nearby channels, leading to an action potential in the adjacent location - Cascade down the axon towards the terminal boutons - Glial cells coat many axons with a fatty layer called myelin - These special cells are the oligodendrocytes in the CNS and Schwann cells in the PNS - The insulating layer of myelin allows the action potential to travel down the axon much faster - Between the myelin segments are open regions called the Nodes of Ranvier, important as the electrical signals jump, lets the signal travel more rapidly - Once the threshold is reached the action potential proceeds to completion without fail, no such thing as a half - Messages are encoded by frequency - Fo
More Less

Related notes for PSYCH 1XX3

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.