Fill in the blanks. Choose the appropriate word or words from the brackets and fill up the blanks:
(a) Messages take the form of electrical signals and are known as ____.(nerves/impulses)
Nerve impulses:
(b) _____ nerves carry impulses from the brain and spinal cord to muscles or glands.(Afferent/Efferent)
(d) ______ increases the speed of impulse along an axon. (Myelin sheath/ Synapse).
(c)An _____ is a change in the environment that may be of sufficient strength to initiate an impulse.(effector/stimulus)
Messages that take the form of electrical signals are known as