Ch.10- Nervous System

24 : The action potential is around -70 mC. a. True b. False

The answer is False The resting potential is -70 mV, and the action potential is +30mV.

20 : The ion moving in a direction opposite to sodium (Na+ ) is potassium (K+). a. True b. False

The answer is True Because of the Na+ - K+ membrane pump, Na+ is always exchanged for K+.

25 : The all-or-none-response means that a subthreshold stimulus can never stimulate a nerve. a. True b. False

Answer is False It can occur if 2 nerves that are both releasing subthreshold stimuli cause summation.

8 : A synapse is a junction between two dendrites. a. True b. False

The answer is False A synapse usually occurs either between an axon and dendrite or axon and soma.

14 : An effector is usually a muscle or motor nerve. a. True b. False

The answer is False An effector is usually a muscle or gland.

17 : Somatic afferent fibers carry sensory impulses away from the brain, towards areas such as the eye. a. True b. False

The answer is False Impulses are carried in these somatic afferent fibers, away from the eye.

12 : Neurotransmitters are usually released into the synaptic vesicles during depolarization. a. True b. False

The answer is False Neurotransmitters are stored in vesicles in the axon.

3 : Nodes of Ranvier are only found on motor axons of the PNS. a. True b. False

The answer is False Nodes of Ranvier can also be found on dendrites.

5 : Either CNS cell body injury or axon damage leads to regeneration of the nerve tissue that was injured. a. True b. False

The answer is False Only damage to an axon is followed by growth of a new cell extension called an axon.

26 : Sodium moves out of an axon as it is depolarizing. a. True b. False

The answer is False Sodium rushes into the axon and potassium moves out during depolarization.

7 : The axon nerve impulse is self-propagating and occurs in the direction towards the cell body. a. True b. False

The answer is False The direction of conduction within a dendrite is towards the soma.

18 : A damaged phrenic nerve would heal more slowly than a severed spinal nerve. a. True b. False

The answer is False The phrenic nerve is a PNS nerve with a Schwann cell neurolemma and would heal faster than a CNS spinal cord fiber without one.

1 : Schwann cells provide a myelin sheath in the CNS. a. True b. False

The answer is False They provide a myelin sheath along axons in the PNS.

13 : Sub-threshold stimuli can never evoke an action potential. a. True b. False

The answer is False Two or more sub-threshold stimuli could result in summation.

4 : A bundle of unmyelinated CNS nerve fibers and cell bodies is known as 'gray matter'. a.True b.False

The answer is True

22 : Calcium channels open during synaptic transmission. a. True b. False

The answer is True Calcium channels allow calcium to move across a neuron membranes during synaptic transmission; some researchers consider calcium to be a neurotransmitter.

6 : A neuron will not respond to any stimulus during its absolute refractory period. a. True b. False

The answer is True A nerve can be made to respond again during the relative refractory period.

15 : Motor neurons usually have one axon and several dendrites. a. True b. False

The answer is True All fibers have only one axon.Motor neurons are also called multipolar because they have several dendrites.

21 : Drugs that hyperpolarize an axon would make the nerve less sensitive to further stimulation. a. True b. False

The answer is True Hyperpolarization causes the resting potential to be greater than -70mV, such as -80mV, thereby making it more difficult to depolarize a neuron.

11 : Food additives, such as MSG (monosodium glutamate) derived from glutamic acid, could act as neurotransmitters. a. True b. False

The answer is True Many chemicals such as monosodium glutamate could stimulate nerves.

23 : Having myelin increases the velocity of conduction. a. True b. False

The answer is True Saltatory conduction is made possible because of the myelin sheath.

16 : Nervous tissue includes areas of connective tissue. a. True b. False

The answer is True There are connective tissue fibers that surround nerve fibers.

9 : Norepinephrine, epinephrine, dopamine and serotonin are monoamine neurotransmitters. a. True b. False

The answer is True They all have an amine, NH2 group; serotonin is not a catecholamines.

2 : Oligodendrocytes can be found within the brain. a. True b. False

The answer is True They produce myelin along CNS nerve fiber bundles also known as 'white matter'.

6 : The _____cells provide a means of acquiring nutrients in the brain. a. astrocyte b. microglia c. ependymal d. oligodendrocyte

The answer is a. astrocyte The astrocytes are part of the blood-brain barrier and therefore supplies nutrients.

15 : Which type of short neuron is found in the retina? a. bipolar b. unipolar c. multipolar d. sensory

The answer is a. bipolar One type of associating neuron in the retina of the eye is the short, bipolar type.

14 : A drug, which prevents over-stimulation by the PNS neurons, is _____. a. curare b. caffeine c. amphetamine d. tricyclic anti-depressant

The answer is a. curare Dilantin is used to prevent the cortical activity that causes convulsive seizures.

4 : Which part of a neuron directly contacts another neuron at the synapse? a. synaptic knob b. dendrite c. axon d. collateral fiber

The answer is a. synaptic knob Axon terminal ends with the synaptic knobs are what synapses with another neuron.

7 : The resting potential of a neuron is _____mV. a. +30 b. -70 c. 0 d. -90

The answer is b. -70 The voltage across a resting axon membrane is -70mv; -90 would represent hyper-polarization and +30 is the action potential.

12 : The following belong together except which one? a. norepinephrine b. acetylcholine c. epinephrine d. adrenalin

The answer is b. acetylcholine Ach is a lecithin (a phospholipid) derivative while the others are amine compounds.

13 : A morphine-like pain suppressing brain substance is _____. a. substance P b. beta-endorphin c. nicotine d. neuropeptide

The answer is b. beta-endorphin Endorphins (beta-endorphins) are compounds that raise the threshold for pain.

5 : The phagocytic cells in the CNS are the ______. a. astrocytes b. microglia c. oligodendrocytes d. ependymal cells

The answer is b. microglia Astrocytes play a role in the blood-brain barrier.

9 : Saltatory conduction occurs when an impulse jumps from _____. a. axon to dendrite b. node to node c. dendrite to axon d. node of Ranvier to axon

The answer is b. node to node Saltatory conduction refers to the occurrence of depolarizations at the nodes of Ranvier.

1 : The central nervous system is comprised of the brain and _____. a. cranial nerves b. spinal cord c. peripheral nerves d. spinal nerves

The answer is b. spinal cord The spinal nerves are part of the PNS.

3 : Which part of a neuron is directly involved with protein synthesis? a. cell body b. neurofibrils c. Nissl body d. neurolemma

The answer is c. Nissl body The cell body contains the Nissl bodies.

18 : The cells that produce myelin in the PNS are the ______. a. oligodendrocytes b. axons c. Schwann cells d. ependymal

The answer is c. Schwann cells Oligodendrocytes produce myelin in the CNS.

10 : The most common neurotransmitter in the body is _____. [Nervous System-NS] a. norepinephrine b. adrenalin c. acetylcholine (Ach) d. dopamine

The answer is c. acetylcholine (Ach) Ach is found in much of the NS and skeletal muscle neuromuscular junctions.

19 : The ______cells play a role in the establishment of a blood-brain chemical barrier. a. microglia b. neuron c. astrocyte d. ependymal

The answer is c. astrocyte The microglia are CNS phagocytic defense cells.

8 : The minimal stimulus needed to cause a neuron to transmit an impulse is called the _____. a. action potential b. resting potential c. threshold d. refractory period

The answer is c. threshold The action potential occurs after stimulation.

11 : Acetylcholine is decomposed by _____almost as fast as it is released. a. monoamine oxidase b. MAO inhibitors c. norepinephrine d. acetylcholinesterase

The answer is d. acetylcholinesterase Monoamine oxidase degrades catecholamines.

2 : The______of a neuron carries the impulse towards the nucleus. a. cell body b. myelin c. axon d. dendrite

The answer is d. dendrite The cell body area contains the nucleus.

16 : The following belong together except which one? a. interneuron b. intercalated neuron c. association neuron d. sensory neuron

The answer is d. sensory neuron Sensory neurons are not central in nature.The other terms refer to central neurons

17 : The PNS is comprised of cranial nerves and _____. a. spinal cord b. sensory nerves c. the brain d. spinal nerves

The answer is d. spinal nerves The 31 pairs of spinal nerves and 12 pairs of cranial nerves comprise the peripheral nervous system.