Given below are sets of five terms each. Rewrite the terms in correct order in a logical sequence beginning with the first word that is underlined.
STIMULUS, Response, Receptor, Effector, Spinal cord.
Topic: Reflex arc
Answer
Stimulus → Receptor → Spinal cord → Effector → Response
This is the REFLEX ARC, traced from the event that starts it to the action that ends it: STIMULUS — the change that triggers everything (a hot object) RECEPTOR — detects it SPINAL CORD — receives the impulse by a sensory neuron and sends an instruction back by a motor neuron EFFECTOR — the muscle or gland that acts RESPONSE — what the effector does
NOTE THE TWO PAIRS AT THE ENDS: STIMULUS and RESPONSE are the EVENTS, RECEPTOR and EFFECTOR are the STRUCTURES. The events come first and last; the structures lie between.
The whole point is that the SPINAL CORD, not the brain, completes the circuit — which is why you pull your hand away before you feel the pain.