The Nervous System and Sense Organs — Biology STD 10 — Question

The stimulation from the nerve cells of the receptor organ passes into the spinal nerve (along the dorsal root) into the spinal cord and from there it goes straight to the brain. From the brain another impulse passes, to the spinal cord and travels along the ventral root of the spinal nerve to reach the effector organ (a muscle), the activity of which is a response to the nerve impulse which has come from the brain.