The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions: The diagram given below shows the internal structure of a spinal cord depicting a phenomenon. Study the diagram and answer the questions:
Name the parts numbered 1, 2 and 3.
Topic: Parts of the reflex arc
Answer
1 — SENSORY NEURON (afferent fibre) 2 — MOTOR NEURON (efferent fibre) 3 — GREY MATTER (with the central canal)
Identify the two neurons by the DIRECTION of their arrows, which is what the diagram shows: SENSORY (afferent) — carries the impulse TOWARDS the spinal cord, entering by the DORSAL root MOTOR (efferent) — carries it AWAY to the effector, leaving by the VENTRAL root
The words settle it: AFFERENT means carrying towards, EFFERENT means carrying away — the same pair as the afferent and efferent arterioles of the kidney.
The GREY MATTER is the butterfly-shaped or H-shaped region in the CENTRE of the spinal cord, made of cytons, with the central canal running through it.