Class Notes (836,277)
Canada (509,737)
Biology (2,256)
BIOL 273 (91)

1e The chemical synapse .doc

2 Pages
Unlock Document

BIOL 273
Norman Scott

1e The Chemical synapse How are signals transmitted between cells? - neurons join to other neurons by gap junctions( set of holes through the membranes that allow electrical signals to pass through from one cell to the other) = electrical synapses - most neurons communicate with other cells CHEMICALLY through CHEMICAL synapses - illustration in notebook - synapse: presynaptic axon terminal, synaptic cleft, postsynaptic dendrite - presynaptic cell: cell that releases the NT - postsynaptic cell: binds the NT - space between the two = synaptic cleft (interstitial fluid) - when NT binds to receptor , it can initiate graded potentials (either depolarizing 'excitatory postsynaptic potential EPSP' or hyper-polarizing 'inhibitory postsynaptic potential IPSP') > receptor is ligand-gated channel Neurotransmitters and Receptors - amount of NT bound to receptors is in equilibrium with the amount that is free in the synaptic cleft - any factor that decreases the amount of free NT reduces the no. of NT-bound receptors: 1) diffusion out of synaptic cleft (NT) 2) degradation by enzymes in the cleft 3) uptake by glial cells or re-uptake by the presynaptic cell (recycle) - only one kind of NT releases and one kind of receptor - in any synapse there's only one kind of GP(signal) to be produced(transmitted) : either excitatory postsynaptic potential or inhibitory postsynaptic potential (not both) - a single neuron can have up to 10,000 synapses !!! ^ - a single axon can have multi branches (axon terminals), a single AP can bring about the release of diff NTs at diff chemical synapses - pre synaptic inhibition vs. pre synaptic facilitation - recently discovered that postsynaptic cell can signal the presynaptic. Allows a bidirectional exchange of information: - presynaptic cell axon terminal is converting electrical signals into chemical signals because the more action potentials it receives the faster it arrives the more NT is released - postsynaptic membrane does the opposite, incoming chemical signals (NT) are converted to electrical signals (GP) - the mor
More Less

Related notes for BIOL 273

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.