Problem sets and polls Flashcards
Threshold stimuli are stimuli that are strong enough to:
repolarize the neuron membrane.
cause a net flux of positively charged ions from inside to outside the cell.
cause a net influx of positively charged Na+ ions from outside to inside the cell.
close potassium channels to the point that an action potential is initiated.
open potassium channels to the point that an action potential is initiated.
cause a net influx of positively charged Na+ ions from outside to inside the cell.
The following steps refer to various stages in transmission at a chemical synapse.
- Neurotransmitter binds with receptors associated with the postsynaptic membrane.
- Calcium ions rush into neuron’s cytoplasm.
- An action potential depolarizes the membrane of the presynaptic axon terminal.
- The ligand-gated ion channels open on the post synaptic membrane.
- The synaptic vesicles release neurotransmitter into the synaptic cleft.
Which sequence of events is correct?
1 → 2 → 3 → 4 → 5
2 → 3 → 5 → 4 → 1
3 → 2 → 5 → 1 → 4
4 → 3 → 1 → 2 → 5
5 → 4 → 3 → 2 → 1
3 → 2 → 5 → 1 → 4
In a resting potential, an example of a cation that is more abundant in the cytosol of a neuron than in the interstitial fluid outside the neuron is:
Cl-
K+
Na+
Ca++
K+
The point of connection between two communicating neurons is called the:
axon hillock
dendrite
synapse
cell body
neuronal connector
Synapse
When two excitatory postsynaptic potentials (EPSPs) occur at a single synapse so rapidly in succession that the postsynaptic neuron’s membrane potential has not returned to the resting potential before the second EPSP arrives, the EPSPs add together, producing:
temporal summation
spatial summation
the refractory state
an IPSP
temporal summation
The transmission of an action potential typically requires the cell membrane to reach threshold in which region?
dendrite
cell body
nucleus
axon hillock
synaptic terminal
axon hillock
Postsynaptic potentials:
A. directly result from the opening of voltage-gated ion channels.
B. may be depolarizing or hyperpolarizing.
C. may be summed.
B and C.
A, B, and C.
A, B, and C.
Which of the following statements concerning the propagation of action potentials is incorrect?
Saltatory conduction occurs in myelinated axons.
During conduction of an action potential, current flows from the active area of the membrane to the adjacent inactive area, thereby bringing the inactive area to threshold.
For fibers of equal diameter, action potential propagation is faster in myelinated fibers than in unmyelinated ones.
Action potential propagation is faster in large-diameter fibers than in small-diameter ones.
Strong stimuli generate stronger action potentials than weaker stimuli.
Strong stimuli generate stronger action potentials than weaker stimuli.
Action potentials move along axons:
more slowly in axons of large diameter than of small diameter.
by the direct action of acetylcholine on the axonal membrane.
by activating the sodium-potassium “pump” at each point along the axonal membrane.
more rapidly in myelinated than in non-myelinated axons.
more rapidly in myelinated than in non-myelinated axons.
Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it. The sodium channel is a:
voltage-gated sodium channel.
voltage-gated potassium channel.
ligand-gated sodium channel.
second-messenger-gated channel.
ligand-gated sodium channel.
The motor (efferent) part of the autonomic nervous system:
contains only preganglionic fibers.
contains only post ganglionic fibers.
has preganglionic neurons that release epinephrine.
provides efferent innervation of skeletal muscle.
functions in the control of smooth and cardiac muscle.
functions in the control of smooth and cardiac muscle.
Short-term memory information processing causes changes in the:
brainstem
medulla
hypothalamus
hippocampus
thalamus
hippocampus
Which cells are immune cells in the central nervous system that protect against pathogens?
astrocytes
Schwann cells
microglia
oligodendrocytes
microglia
Prior to long-term potentiation, glutamate release into the synaptic cleft (gap) opens the NMDA glutamate receptors, but ion movement through the channel is blocked by:
Ca++
Na+
Mg++
K+
Stored AMPA receptors
Mg++
Which cells myelinate axons in the central nervous system?
astrocytes
Schwann cells
microglia
oligodendrocytes
oligodendrocytes
Sometimes you interpret objects to be similar to faces (e.g., a squashed gallon jug of milk looks like a judgy face). Your brain is telling you a story about the world, trying to make sense of all the input. When you see faces in objects, which part of the brain is most directly involved?
Cerebral cortex
Hypothalamus
Cerebellum
Limbic system
Cerebral cortex
Which system controls smooth and cardiac muscles of the digestive, cardiovascular, and excretory systems?
central nervous system
peripheral nervous system
autonomic nervous system
parasympathetic nervous system
sympathetic nervous system
autonomic nervous system
Which cells produce the myelin sheaths that surround axons in the peripheral nervous system?
astrocytes
Schwann cells
microglia
oligodendrocytes
Schwann cells
Which of the following structures or regions is incorrectly paired with its function?
limbic system - motor control of speech.
medulla oblongata - control centers for involuntary functions.
cerebellum - coordination of movement and balance.
corpus callosum - communication between the left and right cerebral cortices.
hypothalamus - regulation of temperature, hunger, and thirst.
limbic system - motor control of speech.
Long-term memory information processing requires that links initially established in the hippocampus are replaced with connections in the:
medulla
pons
cerebellum
cerebral cortex
spinal cord
cerebral cortex
A change in the membrane potential of a neuron from a value of -70mV to a value of -60mV would be called:
A. Depolarization
B. Hyperpolarization
C. Action potential
D. Refractory period
A
Which of the following statements concerning the propagation of action potentials is incorrect?
A. Saltatory conduction occurs in myelinated axons
B. during conduction of an action potential, current flows from the active area of the membrane to the adjacent inactive area, thereby bringing the inactive area to threshold
C. For fibers of equal diameter, action potential propagation is faster in myelinated fibers than in unmyelinated ones
D. Action potential propagation is faster in large-diameter fibers than in small diameter ones
E. Strong stimuli generate stronger action potentials than weaker stimuli
E
In a neuron, resting potential is maintained by maintaining a gradient of:
A. Potassium ions (K+)
B. Sodium ions (Ka+)
C. Both
C
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?
A. Voltage-gated calcium channels in the membrane open
B. Synaptic vesicles fuse with the membrane
C. The postsynaptic cell produces an action potential
D. The postsynaptic cell membrane becomes hyperpolarized
E. Ligand-gated channels open, allowing neurotransmitters to enter the synaptic left
A
