Textbook Notes (363,065)
Canada (158,171)
Psychology (4,731)
Psychology 1000 (1,558)
Chapter 3

Chapter 3.docx

5 Pages
Unlock Document

Western University
Psychology 1000
John Campbell

Chapter 3 Biological foundations of behavior The brain  Brain is a grapefruit sized 3 pound mass of tissue made up of neurons  Neurons are building blocks of nervous system,  At birth brains are made up of 100 billion neurons Neurons  Specialized nerve cells, basic building blocks of nervous system  Send/ receive nerve impulses  Sensory motor interneurons  Two important functions o Generate electricity that creates nerve impulses o Releases chemicals that allow neurons to communicate with others in glands and muscles  Sensory neurons- carry messages from organs to spine and brain  Motor neurons- carry messages from brain and spine to muscles  Interneurons- connective functions with nervous system Nerve activation (three steps) 1) Neuron has electrical resting potential due to +ve and –ve charged chemicals, distributes ions 2) When stimulated, a flow of ions reverses the electrical charge producing an action potential 3) The original distribution of ions is restored, neuron is now at rest again Resting potential- neuron is at rest at around -70 millivolts (charge is generated by ion concentration inside and outside of nucleus) Depolarizing- when the electrical charge rises above – 70  Process- signal is received from the dendrites and charge starts to move toward 0. This is due to “holes” in the membrane where more positive ions enter the cell.  Threshold level: holes reach maximum width and the charge jumps to +40 millivolts (then cell returns to rest) o Sodium and potassium channels (sodium opens for + ions to enter; this is depolarization, potassium opens and sodium closes to restore resting potential) Hyperpolarizing- charge falls below -70 Action potential- sudden reversal of the neurons membrane voltage (moves from rest at -70 millivolts to around +40…aslo associated with depolarization Three important notes! 1) An action potential is generated only in an axon 2) An action potential is all-or-none—an axon either generates an action potential or it fails to do so 3) Time after the positive spike is called the refractionary period; it cannot generate another action potential 3 main parts to a neuron  Cell body (soma)  Dendrites-are the receiving end of a neuron—signals come in through the dendrites. A cell might have thousands of dendrites, branching out to receive signals from various places  Axon- is the transmitting part of the neuron. Here signals will be sent to the dendrites of other neurons  NOTE- a neuron only has 1 axon Glial cells- surround neurons and hold them in place/ protect brain from toxins ( the blood brain barrier) Neural communications  Is an electrochemical process o Electrically charged particles enter the neuron o Action potential continues down the axon o Chemical molecules exit the terminal buttons and attach themselves to adjacent dendrites SYNAPSE  Greek for gap  The site of adjacent neurons Synaptic Transmission  Synaptic transmission- When the action potential reaches the end of the axon, it must be transmitted to the next neuron in line  Presynaptic neuron will communicate with the postsynaptic neuron (axon from one neuron communicates with dendrites of another…THEY DO NOT TOUCH)  Synaptic cleft- separates dendrites and axon  LOOK AT FIG 3.4 Neurotransmitters  When they bind to and adjacent neuron they cause chemical reactions  Found in bags of chemicals that carry messages across the synapse  Excitatory neurotransmitters- when post
More Less

Related notes for Psychology 1000

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.