Synaptic Transmission
Electrical and chemical synapses and neurotransmitter release. (Biology › Neural Control and Coordination, NEET UG syllabus.)
What is Synaptic Transmission?
The junction between two neurons or between a neuron and an effector cell, where information is transmitted.
Key points
- Differentiate between electrical and chemical synapses based on their structure and mechanism.
- Describe the sequence of events involved in chemical synaptic transmission.
- Explain the role of calcium ions in neurotransmitter release.
- Identify the fate of neurotransmitters after binding to postsynaptic receptors.
Common exam trap
Confusing the roles of Na+, K+, and Ca2+ ions in action potential generation vs. synaptic transmission.
Definitions
- Term
Synapse
- Meaning
The junction between two neurons or between a neuron and an effector cell, where information is transmitted.
- Term
Presynaptic Neuron
- Meaning
The neuron that transmits the signal across the synapse.
- Term
Postsynaptic Neuron
- Meaning
The neuron that receives the signal across the synapse.
- Term
Synaptic Cleft
- Meaning
The microscopic gap between the presynaptic and postsynaptic membranes in a chemical synapse.
- Term
Neurotransmitter
- Meaning
A chemical messenger released by a neuron that diffuses across the synaptic cleft and binds to receptors on the postsynaptic neuron, altering its activity.
- Term
Excitatory Postsynaptic Potential (EPSP)
- Meaning
A transient depolarization of the postsynaptic membrane, making it more likely to fire an action potential.
- Term
Inhibitory Postsynaptic Potential (IPSP)
- Meaning
A transient hyperpolarization or stabilization of the postsynaptic membrane, making it less likely to fire an action potential.
- Term
Gap Junction
- Meaning
Specialized intercellular connections that allow direct passage of ions and small molecules between adjacent cells, characteristic of electrical synapses.
- Term
Synaptic Vesicle
- Meaning
Small, membrane-bound sacs within the presynaptic terminal that store neurotransmitters.
Learning objectives
Differentiate between electrical and chemical synapses based on their structure and mechanism.
Describe the sequence of events involved in chemical synaptic transmission.
Explain the role of calcium ions in neurotransmitter release.
Identify the fate of neurotransmitters after binding to postsynaptic receptors.
Distinguish between excitatory and inhibitory postsynaptic potentials (EPSP and IPSP).
Relate synaptic transmission to overall neural communication.
Prerequisites
Basic understanding of neuron structure (axon, dendrite, cell body).
Knowledge of resting membrane potential and action potential generation.
Understanding of ion channels and membrane transport mechanisms.
Familiarity with basic cell biology concepts like exocytosis.
Common mistakes
Confusing the roles of Na+, K+, and Ca2+ ions in action potential generation vs. synaptic transmission.
Assuming all neurotransmitters are excitatory.
Forgetting the role of the synaptic cleft in chemical synapses.
Not understanding that postsynaptic potentials are graded, while action potentials are all-or-none.
Incorrectly identifying the location of voltage-gated Ca2+ channels (presynaptic terminal).
Keywords
Synapse
Electrical Synapse
Chemical Synapse
Neurotransmitter
Synaptic Cleft
Presynaptic
Postsynaptic
Action Potential
Calcium Ions
Exocytosis
Receptors
EPSP
IPSP
Gap Junctions
Acetylcholine
GABA
Glutamate
Practice preview
What is the primary function of a synapse?…
easy
Which of the following correctly describes the sequence of events at a chemical synapse?…
medium
After binding to receptors on the postsynaptic membrane, how are neurotransmitters typically removed from the synaptic cleft to terminate the signal?…
medium