Chapter 7

Choose the incorrect statement: a. Neurotransmitters diffuse across the myelin sheath. b. In an inhibitory synapse, the neurotransmitter makes it less likely that an action potential will be generated in the postsynaptic (after the synapse) neuron. c. Neurotransmitters are stored in synaptic vesicles. d. Most interneurons are found in the central nervous system.

In botulism, a type of food poisoning, the poison produced by bacteria in the spoiled food prevents the person's synaptic vesicles from fusing with the neuron's membrane. You would expect that this effect would a. cause excessive destruction of neurotransmitter in the synaptic cleft. b. destroy myelin. c. prevent the message of the presynaptic cell from reaching the postsynaptic cell. d. cause neurotransmitters to clog the synaptic cleft.

In a resting neuron a. potassium ions are more concentrated outside the membrane than inside. b. the inside is more negative than the outside. c. sodium ions are more concentrated inside than outside. d. action potentials are being generated.

You are a neurophysiologist trying to identify the function of a particular nerve cell. You notice that this nerve cell fires immediately before a person's pinky finger bends. You correctly conclude that this axon a. may be part of a sensory neuron carrying information from the finger toward the brain. b. may be part of a motor neuron carrying information from the brain toward the pinky. c. is without a doubt part of an interneuron. d. is dead.

The synaptic cleft a. is a chemical that allows two neurons to communicate with one another b. is a gap between two neurons. c. is a gap between two Schwann cells forming the myelin sheath. d. allows saltatory conduction.

Choose the correct statement: a. Neurotransmitters diffuse across the myelin sheath. b. An inhibitory neurotransmitter makes it less likely that an action potential will be generated in the presynaptic (before the synapse) neuron. c. Neurotransmitters are stored in synaptic vesicles. d. Most interneurons are found in the peripheral nervous system.

Multiple sclerosis is a disease in which a. patches of myelin are destroyed. b. neurotransmitters can no longer be produced. c. neurotransmitters can no longer be removed from the synapse. d. synaptic vesicles become clogged.

Choose the incorrect statement about ion channels: a. An ion channel is a small pore (opening) through the plasma membrane. b. An ion channel is usually specific for one type of ion. c. \(A n\) ion channel uses cellular energy to pump sodium ions (Na') out of the cell and potassium ions (K') into the cell. d. The opening and closing of ion channels is important in the generation of an action potential.

What is the initial (first) event of an action potential? a. depolarization caused by potassium ions rushing to the inside b. repolarization due to rushing of potassium ions to the inside c. depolarization due to rushing of sodium ions to the inside d. repolarization due to departure of potassium ions from the axon

Repolarization a. establishes the threshold voltage. b. is due to movement of potassium ions out of the axon. c. is due to movement of sodium ions into the axon. d. occurs as the sodium-potassium pump moves potassium out of the axon.

The sodium-potassium pump a. uses energy to move sodium ions out of the cell and potassium ions into the cell. b. can move sodium ions only from an area where they are highly concentrated to an area where they are less concentrated. c. can move potassium ions (K') only toward a region that is positively charged. d. is part of the myelin sheath.

Saltatory conduction a. occurs only in myelinated nerve fibers. b. is slower than other types of nerve conduction. c. occurs only in the central nervous system. d. is the way an impulse gets from one neuron to another.