Direct-acting neurotransmitters ________.
A) require cyclic AMP
B) mediate very slow responses
C) open ion channels to provoke rapid responses
D) act through second messengers
Which of the following is correct relative to Ohm's law?
B) Current is directly proportional to the voltage.
C) R=V + I
D) The more intense the stimulus, the more voltage changes.
Ciliated CNS neuroglia that play an active role in moving the cerebrospinal fluid are called ________.
A) ependymal cells
B) Schwann cells
The sheath of Schwann is also called the ________.
A) myelin sheath
D) white matter
Bipolar neurons are commonly ________.
A) motor neurons
B) called neuroglial cells
C) found in ganglia
D) found in the retina of the eye
An excitatory neurotransmitter secreted by motor neurons innervating skeletal muscle is ________.
D) gamma aminobutyric acid
A neural circuit in which a single impulse is transmitted over and over is a ________.
A) diverging circuit
B) converging circuit
C) reverberating circuit
D) repetitive circuit
The period after an initial stimulus when a neuron is
not sensitive to another stimulus is the ________.
A) resting period
D) absolute refractory period
A neuronal circuit that concentrates or directs a large number of incoming impulses to a rather small number of neurons is called a(n) ________.
A) diverging circuit
B) oscillating circuit
C) converging circuit
D) parallel circuit
Which of the following is
not a structural feature of a neuron?
A) synaptic cleft
B) Nissl bodies
The part of a neuron that conducts impulses away from its cell body is called a(n) ________.
D) Schwann cell
The chemically gated channel, NMDA, allows ________ ions entry into the nerve cell.
The point at which an impulse from one nerve cell is communicated to another nerve cell is the ________.
A) cell body
The role of acetylcholinesterase is to ________.
A) act as a transmitting agent
B) amplify or enhance the effect of ACh
C) destroy ACh a brief period after its release by the axonal endings
D) stimulate the production of serotonin
Which of the following is
not a function of the autonomic nervous system?
A) innervation of smooth muscle of the digestive tract
B) innervation of cardiac muscle
C) innervation of glands
D) innervation of skeletal muscle
Collections of nerve cell bodies outside the central nervous system are called ________.
central nervous system refers to the ________.
A) autonomic nervous system
B) brain, spinal cord, and peripheral nerves
C) brain and spinal cord
D) spinal cord and spinal nerves
The substance released at axon terminals to propagate a nervous impulse is called a(n) ________.
D) biogenic amine
A neuron that has as its primary function the job of connecting other neurons is called a(n) ________.
A) efferent neuron
B) afferent neuron
C) association neuron
D) glial cell
Saltatory conduction is made possible by ________.
A) the myelin sheath
B) large nerve fibers
C) diphasic impulses
D) erratic transmission of nerve impulses
Which of these ions is actively transported through the cell membrane to establish a resting potential?
The part of the neuron that normally receives stimuli is called ________.
A) an axon
B) a dendrite
C) a neurolemma
D) a Schwann cell
Choose the statement that is most correct about membrane potential.
A) Voltage would be measured by placing two electrodes on the exterior of the axon.
B) Voltage would be measured by placing one electrode inside the membrane and another outsidethe membrane.
C) Voltage would be measured by placing one electrode on one end of the axon and another electrode on the other end.
D) Voltage would be measured by placing one electrode on the axon and grounding the other electrode
The sodium- potassium pump ________.
A) pumps three sodium ions outside the cell and two potassium ions inside
B) pumps two sodium ions outside the cell and three potassium ions inside
C) pumps three sodium ions inside the cell and two potassium ions outside
D) pumps two sodium ions inside the cell and three potassium ions outside
An action potential ________.
A) is essential for impulse propagation
B) involves the influx of negative ions to depolarize the membrane
C) is initiated by potassium ion movement
D) involves impulse propagation dependent on chemically gated ion channels
Select the correct statement about synapses.
A) Cells with interconnected cytoplasm are chemically coupled.
B) The release of neurotransmitter molecules gives cells the property of being electrically coupled.
C) Neurotransmitter receptors are located on the axons of cells.
D) The synaptic cleft prevents an impulse from being transmitted directly from one neuron to another.
Which of the following is a good example of a neuromodulator?
B) any protein
C) any carbohydrate
D) nitric oxide
28) Which group of fibers spreads impulses at up to 1 meter per second?
A) group A fibers
B) group B fibers
C) group C fibers
D) group D fibers
The sympathetic and parasympathetic are subdivisions of the ________.
A) central nervous system
B) voluntary nervous system
C) autonomic nervous system
D) somatic nervous system
Ependymal cells ________.
A) are a type of neuron
B) are a type of macrophage
C) are the most numerous of the neuroglia
D) help to circulate the cerebrospinal fluid
Neuroglia that control the chemical environment around neurons by buffering potassium andrecapturing neurotransmitters are ________.
D) Schwann cells
Schwann cells are functionally similar to ________.
A) ependymal cells
Immediately after an action potential has peaked, which cellular gates open?
Nerve cell adhesion molecules (N-CAMs) ________.
A) release nerve growth factor
B) are found on "pathfinder" neurons
C) are crucial in the production of neurotransmitters
D) are crucial for the development of neural connections
An inhibitory postsynaptic potential (IPSP) is associated with ________.
A) a change in sodium ion permeability
C)opening of voltage-regulated channels
D) lowering the threshold for an action potential to occur
Which of the following will occur when an excitatory postsynaptic potential (EPSP) is beinggenerated on the dendritic membrane?
A) Specific sodium gates will open.
B) Specific potassium gates will open.
C) Sodium gates will open first, then close as potassium gates open.
D) A single type of channel will open, permitting simultaneous flow of sodium and potassium.
When a sensory neuron is excited by some form of energy, the resulting graded potential is called a(n) ________.
A) postsynaptic potential
B) excitatory potential
C) action potential
D) generator potential
All of the following are true of graded potentials except that they ________.
B) can form on receptor endings
C) increase amplitude as they move away from the stimulus point
D) can be called postsynaptic potentials
Which of the following is true about the movement of ions across excitable living membranes?
A) Ions always move actively across membranes through leakage channels.
B)Some ions are prevented from moving down their concentration gradients by ATP-driven pumps.
C) Sodium gates in the membrane can open in response to electrical potential changes.
D) The bulk of the solutions inside a cell are negatively charged.
A second nerve impulse cannot be generated until ________.
A) the membrane potential has been reestablished
B) the Na ions have been pumped back into the cell
C) proteins have been resynthesized
D) all sodium gates are closed
In what way does the interior surface of a cell membrane of a resting (nonconducting) neuron differ from the external environment? The interior is ________.
A) positively charged and contains less sodium
B) negatively charged and contains less sodium
C) negatively charged and contains more sodium
D) positively charged and contains more sodium
If a motor neuron in the body were stimulated by an electrode placed about midpoint along the length of the axon ________.
A) the impulse would move to the axon terminal only
B) muscle contraction would occur
C) the impulse would spread bidirectionally
D) the impulse would move to the axon terminal only, and the muscle contraction would occur
Neurons may be classified according to several characteristics. Which of the following is correct?
A) Group A fibers are mostly somatic sensory and motor and are the smallest in diameter.
B) Group B fibers are highly myelinated and have the highest conduction velocities.
C) Group C fibers are not capable of saltatory conduction.
D)A small cross-sectional area allows shorter conduction times