Label the parts (a), (b), (c), and (d) and show the direction of flow of electrical signals in Figure 7.2.
The direction of flow of the electrical signal is as follows:
(a) Sensory neuron- It receives the signals (heat) from the stimulus (hot pan) and carries it directly to the spinal cord.
(b) Spinal cord (CNS)- It is a cylindrical structure that carries bundles of nerve fibers. It receives the signal from the sensory neurons and processes and sends them back through the motor neurons.
(c) Motor neuron- It transmits the signals to the effector muscle (muscle in the arm) so that the muscle can take action immediately.
(d) Effector (Muscle in the arm)- They act in response to the stimuli and show contraction.