Univ. of Illinois, Urbana-Champaign Bio/Neuro 303 EXAM I Study Questions 209. At chemical synapses, the ion thought to be necessary inside the presynaptic cell to facilitate the release of transmitter is a. Na+. *b. Ca2+. c. K+. d. Cl-. 210. One important role of calcium ions at a chemical synapse is to a. act as a transmitter substance. b. facilitate the binding of the transmitter substance with receptor molecules in the post-synaptic membrane. c. aid in the inactivation of the transmitter. *d. facilitate the release of transmitter from the pre-synaptic terminal. 211. In chemical synaptic transmission, the Ca2+ that is necessary for release of the transmitter substance a. is already present in the presynaptic cell as free Ca2+. b. is released by the AP from internal stores of bound Ca2+. *c. enters the presynaptic cell from the extracellular fluid. d. comes from the synaptic vesicles themselves. 212. The protein that has been shown to form a cage-like barrier around clear synaptic vesicles is known as *a. synapsin I. b. kinesin. c. tubulin. d. kinysin I. 213. Synapsin I is the protein that a. forms microtubules in neurons. *b. forms a barrier around synaptic vesicles. c. acts to move particles in the anterograde direction along the length of an axon during axoplasmic transport. d. is part of the presynaptic membrane responsible for releasing transmitter substance. 214. Synapsin-I is a protein that a. is involved in anterograde axoplasmic transport of synaptic vesicles. b. is involved in retrograde axoplasmic transport of synaptic vesicles. *c. is involved in binding synaptic vesicles to the presynaptic cytoskeleton. d. is part of the postsynaptic membrane responsible for stabilizing the synapse. 215. The individuals largely responsible for demonstrating that transmitter release could be quantal were a. Hodgkin and Huxley. b. Hodgkin and Katz. *c. Katz and Miledi. d. Eccles and Miledi. 216. The person(s) largely responsible for describing the quantal nature of neuromuscular transmission was (were) a. Ochs. b. Golgi. *c. Katz & Miledi. d. Eccles. 217. The vesicular hypothesis of synaptic transmission states that a. the presence of vesicles in an electron micrograph of nerve cells defines the presence of a synapse. b. vesicles are manufactured in the soma and transported to synapses by axoplasmic transport. c. vesicles are the site of synthesis of transmitter substance. *d. transmitter is packaged in the vesicles and released quantally from them into the synaptic cleft. 218. In the vesicular hypothesis of synaptic transmission, the ______ in discrete particles called vesicles. a. electrical charges associated with the action potential are thought to be packaged b. electrical charges associated with the post-synaptic potential are thought to be packaged *c. transmitter substance is thought to be packaged d. calcium ions are thought to enter the pre-synaptic cell 219. Miniature end plate potentials (mepps) are a. the small changes in the presynaptic membrane potential generated each time a Ca2+ ion enters the cell. b. the random opening of ion channels in the postsynaptic muscle cell membrane in the absence of any electrical or chemical stimulus. *c. small depolarizations of muscle cell membrane due to the random release of packets of transmitter substance, in the absence of any stimulation. d. the small "reference" spike in the end plate that occurs before facilitation takes place. 220. Quantal release of neurotransmitter refers to the fact that a. Only one molecule is released at a time. *b. Transmitter is released in packets (units). c. Only one axon releases transmitter at a given instant. d. Only one packet of transmitter is released at a time. 221. Miniature end plate potentials are thought to represent a. leakage of molecular transmitter. b. the effect of calcium leakage into the presynaptic neuron. *c. leakage of quantal packets of transmitter substance. d. the prelude to an action potential. 222. Quantal transmission refers to *a. the release of transmitter in discrete packets. b. transmission from non-spiking neurons only. c. incremental effect of pre-synaptic inhibition. d. transmission at a neuromuscular junction only. 223. Miniature end plate potentials (mepps) are a. the small changes in the presynaptic membrane potential each time a Ca2+ ion enters the cell. b. the random opening of ion channels in the postsynaptic muscle cell membrane in the absence of any electrical or chemical stimulus. *c. small depolarizations of muscle cell membrane due to the random release of packets of transmitter substance, in the absence of any stimulation. d. the small "reference" spike in the end plate that occurs before facilitation takes place. 224. The phrase "quantal transmission" refers to a. the all or none characteristic of an action potential. b. the transmission of discrete packets of transmitter (quanta) along axons by axoplasmic transport. *c. the release of transmitter substance in discrete packets (quanta) at a synapse. d. the communication of one spiking neuron with another in units (quanta) represented by action potentials. 225. During chemical synaptic transmission, which of the following sequences of events occurs in a presynaptic neuron? a. Depolarization of the terminal --> Ca2+ entry --> AP in axon --> vesicle fusion --> transmitter release. *b. AP in axon --> depolarization of the terminal --> Ca2+ entry --> vesicle fusion --> transmitter release. c. Ca2+ entry --> AP in axon --> depolarization of the terminal --> vesicle fusion --> transmitter release. d. AP in axon --> Ca2+ entry --> depolarization of the terminal --> vesicle fusion --> transmitter release. 226. Synaptic transmission from nonspiking neurons is referred to as graded because *a. the amount of transmitter released is proportional to the membrane potential. b. transmitter is not released in discrete packets. c. the amount of transmitter released depends on the graded size of the EPSP. d. larger neurons release more transmitter substance than do smaller ones. 227. A nonspiking neuron *a. continually releases transmitter substance in a graded fashion. b. does not generate action potentials because it uses only electrical synaptic transmission. c. is an inhibitory type of neuron that reacts by hyperpolarizing when it is stimulated. d. does not generate action potentials because it totally lacks Na+ channels. 228. Re-uptake is the process of entry of transmitter a. precursor molecules into a neuron after synaptic transmission. *b. molecules into a neuron after synaptic transmission. c. molecules through post-synaptic binding sites. d. precursor molecules into a neuron before synaptic transmission. 229. Nearly all amino acid and amine transmitter substances appear to be inactivated mainly by the process of a. enzymatic breakdown. b. chemical sequestration. c. diffusion. *d. re-uptake. 230. Re-uptake is a. the pumping of K+ into the cell after the passage of an AP. b. retrograde transport that prevents too much pressure in the axonal ending. c. the normalization of the levels of endorphin after a patient is cured of morphine addiction. *d. absorption of transmitter into a neuron. 231. Acetylcholine seems unusual among non-peptide transmitter substances in that it a. can cause an action potential directly in the synaptic membrane. *b. is inactivated entirely by extracellular enzymatic breakdown. c. is usually found together with a neuromodulatory co-transmitter. d. can act directly on axonal membrane to cause the opening of voltage-sensitive sodium channels. 232. One neurotransmitter substance that is inactivated entirely by enzymatic breakdown is *a. acetylcholine. b. serotonin. c. norepinephrine. d. GABA. 233. A method for locating some specific transmitter pathways in the brain is a. the Golgi silver stain. b. iontophoresis. c. intracellular staining. *d. the histofluorescence method. 234. The synthetic pathway for norepinephrine is a. tyrosine --> DA --> DOPA --> NE. b. tyrosine --> DOPA --> DA --> adrenaline --> NE. *c. tyrosine --> DOPA --> DA --> NE. d. tyrosine --> adrenaline --> DA --> DOPA --> NE. 235. Part of the synthetic pathway for catecholamines in the nervous system is *a. tyrosine --> DOPA --> DA --> NE. b. tyrosine --> DA --> DOPA --> NE. c. tryptophan --> DOPA --> NE --> serotonin. d. tryptophan --> DOPA --> DA --> NE. 236. Tryptophan is a precursor of a. MAO. *b. serotonin. c. norepinephrin. d. COMT. 237. Tyrosine is a precursor of a. MAO. b. serotonin. *c. norepinephrine. d. COMT. 238. The enzyme MAO acts in the *a. degradation of serotonin. b. degradation of acetylcholine. c. synthesis of dopamine. d. synthesis of acetylcholine. 239. Octopamine is a(n) a. amino acid. b. catecholamine. *c. monoamine, but not a catecholamine. d. peptide. 240. Serotonin is a(n) a. amino acid. b. catecholamine. *c. monoamine, but not a catecholamine. d. peptide. 241. Proctolin is a(n) a. amino acid. b. catecholamine. c. monoamine, but not a catecholamine. *d. peptide. 242. Glutamate is a(n) *a. amino acid. b. catecholamine. c. monoamine, but not a catecholamine. d. peptide. 243. Dopamine is a(n) a. amino acid. *b. catecholamine. c. monoamine, but not a catecholamine. d. peptide. 244. Acetylcholine is known to be a transmitter substance at *a. the vertebrate neuromuscular junction. b. the arthropod neuromuscular junction. c. synapses in the substantia nigra. d. synapses involved in transmission of pain. 245. Acetylcholine is the transmitter substance at a. the insect neuromuscular junction. *b. the vertebrate neuromuscular junction. c. presynaptic facilitating neurons in Aplysia. d. none of the above. 246. Which of the following substances is NOT considered a realistic candidate for a transmitter substance? *a. Vitamin C. b. Glycine. c. Acetylcholine. d. Serotonin. 247. Compared to other regions of the vertebrate brain, brainstem nuclei seem especially rich in a. acetylcholine. b. substance P. *c. 5-hydroxytryptamine. d. octopamine. 248. Most of the neurons whose cell bodies are in the Substantia nigra use ______ as a transmitter substance. *a. dopamine b. serotonin c. norepinephrine d. Substance P 249. The histofluorescence technique involves the a. production of fluorescent histones in the tissue to be studied. *b. interaction of chemicals in the tissue under study with formaldehyde to form a fluorescent material. c. histological study of the distribution of naturally occurring fluorescent materials. d. measurement of the amount of fluorescent antibodies in tissue after appropriate chemical treatment. 250. _____ is found in high concentration in the dorsal root ganglia and the spinal cord of vertebrates. a. Acetylcholine b. Serotonin c. Endorphins *d. Substance P 251. Destruction of the Raphe nuclei or injection of certain drugs in cats causes insomnia. Injection of 5-HTP relieves this insomnia, suggesting that a. 5-HTP can be used to induce sleep. *b. serotonin may be the transmitter in brain pathways that control sleep. c. cats have neuron centers for both sleeping and wakefulness. d. dopamine may be the transmitter in brain pathways that control sleep. 252. Neurons in the Raphe nuclei seem to use which transmitter substance? *a. Serotonin. b. Dopamine. c. Octopamine. d. Epinephrine. 253. As you read this question, you find yourself getting more and more sleepy. It is likely that certain parts of your nervous system are experiencing a high level of a. Acetylcholine. *b. serotonin. c. dopamine. d. norepinephrine. 254. The medical importance of knowing the synthetic pathway for a specific transmitter in humans is demonstrated by the present treatment for a. schizophrenia. b. alcoholism. *c. Parkinson's disease. d. extreme pain in terminally ill individuals. 255. In the treatment of Parkinson's disease, L-DOPA is used as medication because a. it is necessary to avoid bringing on the symptoms of schizophrenia. b. dopamine is present in neurons of the Raphe nuclei that seem to cause the disease. *c. the neural deficit seems to be in neurons that use DA as a transmitter. d. L-DOPA can readily be converted to 5-HT, the substance that actually has the therapeutic effect. 256. Dopamine is not effective as a treatment for Parkinson's disease because a. the deficit causing the disease is a deficiency of serotonin, not dopamine. b. injections of dopamine cause an immunological reaction that render it ineffective. c. the deficit causing the disease is a deficiency of norepinephrine, not dopamine. *d. dopamine cannot cross the blood-brain barrier. 257. Some of the peptide neurotransmitter substances seem to be especially involved in a. hunger. *b. pain. c. thirst. d. neuromuscular control. 258. A placebo may act to reduce pain by inducing the brain to *a. increase endorphin levels. b. increase substance P levels. c. selectively block some neuromuscular transmission. d. increase blood glucose levels. 259. Endogenous (internal) levels of endorphin in humans are LOWERED by a. giving birth. b. taking a placebo against pain. c. acupuncture. *d. addiction to opium.