1. Which of the following terms describes a skin region supplied by a single spinal nerve? a. dermatome 1. b. ganglion c. plexus d. synapse 2. Which of these structures would be most abundant in white matter? a. dendrites 2. b. neuron cell bodies c. myelinated axons d. unmyelinated axons 3. Which of the following are effectors of the nervous system? a. sensory neurons and ganglia 3. b. receptors and neurotransmitters c. synapses and dendrites d. muscles and glands 4. Where would you find cell bodies of somatic sensory neurons? a. dorsal root of the spinal cord b. sympathetic chain c. ventral root of the spinal cord d. effector organ 5. Which of the following substances is a neurotransmitter? a. myelin b. actin c. epinephrine d. sebum 6. What happens during the falling phase of the action potential? a. sodium ions enter the neuron. b. potassium ions leave the neuron. c. sodium ions leave the neuron. d. potassium ions enter the neuron. 7. Which neuron type conveys impulses within the spinal cord? a. sensory neurons b. motor neurons c. mixed nerves d. interneurons.