Class Notes (837,485)
Canada (510,274)
Psychology (1,975)
PSY 324 (44)

Biological Psychology- Lecture 3

4 Pages
Unlock Document

PSY 324
Tara M Burke

Chapter 3 – Synapses *Alcoholism not on midterm* - Threshold of excitation reached  Ion channels open at axon hillock  signal moves down axon (non-decrementing)  signal reaches terminal buttons - Neurons communicate with one another via synaptic transmission of neurotransmitters (Ligand will bind to a specific binding site which will produce postsynaptic potential) - Presynaptic Membrane: Lies opposite to the postsynaptic membrane, where the neurotransmitters are released - Dendritic Spine: Increases surface area Components of the Synapse - Synaptic cleft, synaptic vesicle, release zone, post-synaptic density - Neurotransmitters are produced in the cell body and in the terminal buttons Communication Between Neurons - Structure of the synapses: Synapses occur in 3 places… 1) On dendrites= axodendritic synapse 2) On the soma= axosomatic synapse 3) On other axons= axoaxonic synapse How do we know a synapse exists? Properties of a synapse: 1) Reflexes are slower than conductions along and axon (there must be a gap causing this time lapse) Synaptic Delay: Something is slowing down the transmission of communication 2) Many weak stimuli presented at slightly different times/ locations around the same time produce a stronger reflex than a single stimulus alone (multiple is better than single)- Temporal Summation: neuron A should repeatedly apply stimulation to help neuron B to reach the required threshold (depolarization). Spatial Summation: If there are 3 points of stimulation it will also help the neuron to reach threshold (depolarization) 3) Law of Reciprocal Innervation: When one set of muscles becomes excited, a different set becomes relaxed - Excitatory: tells muscle to flex - Inhibitory: tells antagonistic muscle to relax - EPSP= excitatory post-synaptic potentials Depolarization, increase Na+ into the cell - IPSP= inhibitory post-synaptic potentials Hyperpolarization to prevent stimulation of the neuron, increasing flow of K+ or out or Cl- into cell Steps for Synaptic Neural Communication 1) Synthesis and release of neurotransmitters from presynaptic terminals - Synthesis in soma/ terminal buttons - Calcium channels open (calcium is waiting for depolarization in order for the gates to open and allow for calcium to enter)- if the terminal button is not stimulated, calcium will not enter - Exocytosis: synaptic vesicle fuses with membrane - Vesicles break open and release neurotransmitters into synaptic cleft 2) Activation of the Postsynaptic receptors - Postsynaptic receptor - Neurotransmitter-dependent ion channel 2 Ways neurotransmitters open ion channels… 1) Ionotropic receptor: contains a binding site for neurotransmitters & ion channel that opens when a molecule of the neurotransmitter attaches to binding site (fast acting) 2) Metabotropic receptor: activates an enzyme that begins a series of events that opens ion channels somewhere else in the cell (Slow acting)- effect is stonger and lasts longer even though it is a slower process - G protein: conveys messages to molecules when a ligand binds with & activates the receptor Binding of ligand to receptor  G protein inside membrane activates  activates enzyme that stimulates second messenger  second messenger travels through cytoplasm to ion channel  Opening of ion channel - Second messenger: che
More Less

Related notes for PSY 324

Log In


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.