At a chemical synapse a fluid-filled synaptic cleft separates a presynaptic terminal from the postsynaptic membrane. Arrival of an action potential triggers transmitter release from vesicles in the presynaptic knob. The transmitter diffuses across the cleft and binds specific receptors on the postsynaptic cell, which can open ion channels and change membrane potential.

The resulting response may excite or inhibit the receiving cell; a released chemical does not guarantee a new action potential. Conduction across a typical chemical synapse is physiologically directional from releasing terminal to receptor-bearing receiving membrane. For illustrative delay arithmetic only, if each model synapse adds 0.5 millisecond, three such synapses add 1.5 milliseconds; this number is supplied by the question, not a fixed NCERT human delay.

Worked example: Three model chemical synapses each adding 0.5 ms give 3 × 0.5 = 1.5 ms total synaptic delay.

NCERT trap: Presynaptic vesicles release transmitter; postsynaptic receptors bind it, and the effect may inhibit.

NEET method: Trace terminal → vesicle → cleft → receptor → potential and add only supplied model delays.

Reading estimate; allow another 3–5 minutes for each set of three checks.

Neural Control and Coordination

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