Question

Synaptic delay is the time taken between
a. The actual reception of a stimulus and its perception
b. The reception of a stimulus and the resultant sensory reaction
c. The release of a neurotransmitter from one neuron and the stimulation of the next neuron
d. The conduction of nerve impulse across a neuron

Answer 1

Hint: In the nervous system the structure allows one neuron[nerve cell] to transmit the signal (chemical and electrical) to another nerve or the target effector cell is called the synapse. Synapses are the highly specialized contacts between nerve cells that transmit signals from the presynaptic neuron to the postsynaptic neuron

Complete answer:
The synaptic connection that is found between a muscle cell and a neuron is known as a neuromuscular junction. Most synapses transmit chemical signals by using messengers known as a chemical messenger. Other synapses are electrical ions that flow directly between cells. In a chemical synapse, the terminal end of each nerve fibre [presynaptic fibre] forms a structure that resembles a knoblike that is separated from the adjacent postsynaptic fibre, by the synaptic cleft.

The synaptic cleft is the microscopic space found between the two nerves in the chemical synapse. The typical synaptic cleft is 0.02 micron wide. The neurotransmitter transmits the nerve impulse to the postsynaptic fibre by diffusing across the synaptic cleft and binding to the postsynaptic membrane.

The time interval that occurs between the peak of inward current by the presynaptic membrane and the start of inward current by the postsynaptic membrane is called synaptic delay. Synaptic delay at a single endplate spot has a minimum value of 0.4 to 0.5 ms and a modal value of about 0.75ms. The transmission of the chemical synapse is normally unidirectional, and the electrical synaptic transmission involves a specific structure called gap junctions.

Hence, the correct answer is option (C).

Note: In many synapses, the presynaptic part is located on an axon and the postsynaptic part is located on a dendrite or soma. Mostly the presynaptic endings release mediators by nerve impulse influence. The synaptic delay is needed to release chemical signals by the transmitter, diffusion of the chemical signal across the cleft and lastly the binding of chemicals with the receptors that are present at the postsynaptic membrane.