synapse1
TRANSCRIPT
Synapse
Outline Review the Action Potential What happens when the action potential
reaches the axon terminal? Synaptic Connections Neurotransmission Types of Receptors
Ionotropic vs. Metabotropic Excitation vs. Inhibition
Temporal vs. Spatial Summation Neurotransmitters
3 Types of Synaptic Connections Between Neurons
Neurotransmission at the Synapse
Lifecycle of Synaptic Vesicle
Two Types of Receptors
Ionotropic Metabotropic
Channel opens in response to ion binding
Contains 4-5 subunits that make up the receptor structure
Fast speed of action
• Channel opens in response to second messengers
• Contains 1 subunit that makes up the receptor structure
• Slow speed of action
Ionotropic Receptor
Metabotropic Receptor
Second Messenger Systems Downstream
effects through a series of enzymatic reactions
Nitric oxide
Receptors can have an excitatory or inhibitory effect.Excitatory Postsynaptic Potential (EPSP)
Inhibitory Postsynaptic Potential (IPSP)
Promotes excitation of the postsynaptic membrane
Graded potential that decays over time and space
Cumulative effect of EPSPs are the basis for temporal and spatial summation
Temporary hyperpolarization of a membrane- prevent action potentials How?
Summation
Temporal Summation Spatial Summation
Many stimuli in a close span of time
Repeated stimuli can have a cumulative effect and can produce a nerve impulse when a single stimuli is too weak
Many neurons firing simultaneously in the same location
Synaptic input from several locations can have a cumulative effect and trigger a nerve impulse
Temporal Summation
Excitation or Inhibition of a Muscle
Long Term Potentiation (LTP) Creating new or stronger synapses
Occurs by repeated stimulation, an increase in dendritic receptors, an increase in neurotransmitters
New synapses can be formed in the olfactory system and in the hippocampus
Neurotransmitters
Small Molecule Large Molecule
Glutamate GABA
Dopamine Norepinephrine Serotonin
Acetylcholine
Neuropeptides
Lipids
Gases