Which of these are the first and last elements in a spinal reflex?
a) axon and dendrite
b) sense organ and muscle effector
c) motor neuron and sensory neuron
d) ventral horn and dorsal horn
Impulse travel very rapidly along nerves to the leg of a man. Which fact accounts for the speed at which they travel?
a) the nerves contain myelinated fibers
b) a nerve impulse is an all or none phenomenon
c) there is a potential difference across the axon membranes
d) there is high concentration of Na+ ions inside the axons
