Synapse and Synaptic Transmission
Describes the structure of a synapse, the types (electrical and chemical), and the mechanism by which nerve impulses are transmitted across the synaptic cleft.
What is Synapse and Synaptic Transmission?
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
Key points
- Define synapse and its types.
- Explain the mechanism of synaptic transmission in chemical synapses.
- Differentiate between electrical and chemical synapses.
- Identify the roles of neurotransmitters and receptors.
Common exam trap
Confusing the direction of impulse transmission (always unidirectional across a chemical synapse).
Definitions
- Term
Synapse
- Meaning
A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
- Term
Synaptic cleft
- Meaning
The microscopic gap between the presynaptic and postsynaptic membranes of a synapse.
- Term
Neurotransmitter
- Meaning
A chemical substance released at the end of a nerve fiber by the arrival of a nerve impulse that alters the activity of a target cell.
- Term
EPSP (Excitatory Postsynaptic Potential)
- Meaning
A temporary, localized change in the postsynaptic membrane that, if it reaches threshold, can initiate an action potential.
- Term
IPSP (Inhibitory Postsynaptic Potential)
- Meaning
A temporary hyperpolarization or change in the postsynaptic membrane that inhibits the generation of an action potential.
- Term
Gap Junction
- Meaning
A protein-lined channel in the plasma membranes of adjacent animal cells that directly connects the cytoplasm of the two cells.
Learning objectives
Define synapse and its types.
Explain the mechanism of synaptic transmission in chemical synapses.
Differentiate between electrical and chemical synapses.
Identify the roles of neurotransmitters and receptors.
Understand the concepts of EPSP and IPSP.
Prerequisites
Structure of a neuron (axon, dendrite, cell body)
Action potential generation and propagation
Membrane potential (resting, depolarization, repolarization)
Common mistakes
Confusing the direction of impulse transmission (always unidirectional across a chemical synapse).
Mistaking the roles of presynaptic and postsynaptic neurons.
Forgetting the role of neurotransmitter removal in signal termination.
Not distinguishing between EPSP and IPSP effects.
Practice preview
The influx of which specific ion into the presynaptic terminal is directly responsible for triggering the fusion of synaptic vesicles and the release of neurotransmitters?…
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Which component of a chemical synapse is responsible for releasing neurotransmitters into the synaptic cleft?…
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What is the correct sequence of events that leads to neurotransmitter release at a chemical synapse?…
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