31) The term neurotransmitter refers to a. a chemical found in the synaptic vesicles that is released into the synapse. b. any one of a number of chemical compounds that increase the activity of the endocrine system. c. the chemical substance found in the cell membrane. d. the DNA contained in the nucleus of every neuron. 32) According to your text, ________________ work in a manner similar to how gel capsules filled with cold medicine work. a. synapses b. synaptic vesicles c. axon terminals d. neurotransmitters 33) Neurotransmitters are released from the _________________ and received or detected by the ________________. a. dendrites; axon terminals b. presynaptic membrane; postsynaptic membrane c. cell body; dendrites d. postsynaptic membrane; presynaptic membrane 34) Glial cells a. form the blood-brain barrier. b. promote neuronal healing. c. protect neurons. d. All of the above 35) Which of the following was/were once thought to be about ten times more numerous than neurons? a. Glial cells b. Myelin sheath c. Nodes of Ranvier d. Axons 36) The blood-brain barrier, which keeps harmful molecules from entering the brain, is composed of _______________ that form a fatty coating around tiny blood vessels. a. myelin sheath b. glial cells c. the Nodes of Ranvier d. neurotransmitters 37) A cell in the human nervous system whose primary function is to provide insulation and structure for neurons on which they may develop and work is called a(n) a. epidermal cell. b. glial cell. c. myelin cell. d. adipose cell. 38) What is the function of the myelin sheath? a. to serve as a structure for neurons b. to monitor neural activity c. to speed up the neural impulse d. to produce neurotransmitters 39) One purpose of the ____________________ is to speed up the neural message travelling down the axon. a. receptor site b. axon terminal c. myelin sheath d. synaptic vesicle 40) A fatty substance that is wrapped around the shaft of axons in the nervous system and whose function is to insulate neurons and speed up the neural impulse is called a a. synaptic vesicle. b. dendrite. c. glial cell. d. myelin sheath.