Give an account of synaptic transmission.
The biological process by which a neuron communicates with a target cell across a synapse.
A nerve impulse is transmitted from one neuron to another neuron through junction called synapses.
There are two types of synapses a) Electrical synapses b) Chemical synapses
- Electrical synapses
These synapses are electrically conductive links between two neurons and are also called ‘gap junctions’. Impulses transmission across an electrical synapse is always faster than that across a chemical synapse.
- Chemical synapses
Chemicals called neurotransmitters are involved in the transmission of impulses at those synapses. When an impulse arrives at the axon terminal, it depolarises the membrane opening voltage-gated calcium channels.
Calcium ions stimulate the release of neurotransmitters in the cleft by exocytosis.
The released neurotransmitters bind to their specific receptors, present on the postsynaptic membrane.
The postsynaptic membrane has ligand channels.
They are ion channels which respond to chemical signals, rather than to changes in the membrane potential.
The entry of ions can generate a new potential in the postsynaptic neuron.
The new potential developed may be either excitatory or inhibitory.
Excitatory postsynaptic potentials cause depolarization, whereas inhibitory postsynaptic potential cause hyperpolarisation of the postsynaptic membrane.
The biological process by which a neuron communicates with a target cell across a synapse.
A nerve impulse is transmitted from one neuron to another neuron through junction called synapses.
There are two types of synapses a) Electrical synapses b) Chemical synapses
- Electrical synapses
These synapses are electrically conductive links between two neurons and are also called ‘gap junctions’. Impulses transmission across an electrical synapse is always faster than that across a chemical synapse.
- Chemical synapses
Chemicals called neurotransmitters are involved in the transmission of impulses at those synapses. When an impulse arrives at the axon terminal, it depolarises the membrane opening voltage-gated calcium channels.
Calcium ions stimulate the release of neurotransmitters in the cleft by exocytosis.
The released neurotransmitters bind to their specific receptors, present on the postsynaptic membrane.
The postsynaptic membrane has ligand channels.
They are ion channels which respond to chemical signals, rather than to changes in the membrane potential.
The entry of ions can generate a new potential in the postsynaptic neuron.
The new potential developed may be either excitatory or inhibitory.
Excitatory postsynaptic potentials cause depolarization, whereas inhibitory postsynaptic potential cause hyperpolarisation of the postsynaptic membrane.
