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WorksheetsOrganization and Nerve Cell
Total questions: 20
Worksheet time: 40mins
The nervous system
maintains homeostasis.
interprets or assesses information.
monitors internal and external stimuli.
all of these choices are correct.
The __________ nervous system communicates with the skeletal muscles and the __________ nervous system communicates with the smooth and cardiac muscle as well as glands.
enteric; somatic
autonomic; enteric
enteric; autonomic
somatic; autonomic
The peripheral nervous system includes the __________.
brain
spinal cord
cranial nerves
blood-brain barrier
The central nervous system includes the __________.
spinal cord
spinal nerves
cranial nerves
sensory receptors
The neurons that conduct information towards the CNS are _________.
interneurons
motor neurons
sensory neurons
efferent neurons
Glial cells that are directly involved in defending the CNS against infection and injury include _____________.
microglial cells
ependymal cells
both astrocytes and microglial cells
both ependymal and microglial cells
The concentration of __________ ions is much greater outside the cell as compared to inside the cell, whereas the concentration of ____________ ions is much greater inside the cell as compared to outside the cell.
sodium; chloride
sodium; potassium
potassium; sodium
potassium; chloride
Which of the following statements best describes the movement of ions across the plasma membrane?
The membrane potential is contributed to only by ions with a positive charge.
The ion channels contributing to the membrane potential are unidirectional.
Movement of K+ ions depends on the concentration of Na+ ions to either side of the membrane.
Each ion species follows its own diffusion gradient, regardless of differences in the concentration of other ion species.
Depolarization occurs because
more sodium ions diffuse into the cell than potassium ions diffuse out of it.
the inactivation gates of the voltage-gated sodium ion channels begin to open, and the diffusion of sodium ions decreases.
the extra efflux of potassium ions causes the membrane potential to become slightly more positive than the resting value.
potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close.
Hyperpolarization, or afterpotential, occurs because
more sodium ions diffuse into the cell than potassium ions diffuse out of it.
the inactivation gates of the voltage-gated sodium ion channels begin to open, and the diffusion of sodium ions decreases.
potassium ions continue to diffuse out of the cell after the inactivation gates of the voltage-gated sodium ion channels begin to close.
the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level.
When traveling along an axon, the cell membrane immediately ahead of an action potential depolarizes because of ____________.
membrane receptors
diffusion of sodium current
the sodium/potassium pump
decreased membrane permeability
Structures called ___________ are involved in electrical synapses.
microvilli
desmosomes
gap junctions
tight junctions
What is the correct order for the events of neurotransmitter release from the synaptic terminal?
1) Extracellular Ca2+ enters terminal and binds to sensor protein in the cytoplasm
2) Exocytosis of neurotransmitter into synaptic cleft
3) Action potential reaches axon terminal
4) Ca2+-protein complex stimulates fusion of the docked synaptic vesicle with the plasma membrane
5) Voltage-gated Ca2+ channels open
1, 2, 3, 4, 5
3, 1, 5, 4, 2
3, 5, 1, 4, 2
5, 1, 4, 2, 3
An action potential arriving at the presynaptic terminal causes
voltage-gated sodium ion channels to open, and sodium ions to diffuse into the cell.
voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell.
ligand-gated sodium channels to open, and sodium ions to diffuse out of the cell.
voltage-gated sodium ion channels to open, and sodium ions to diffuse out of the cell.
Along myelinated axons of the peripheral nervous system, ion currents must cross the plasma membrane of the neuron
at nodes of Ranvier.
through satellite cells.
through Schwann cells.
through oligodendrocytes.
Nervous tissue of the CNS that is composed primarily of myelinated axons is often referred to as ______ matter.
light
dark
gray
white
Identify the correct sequence of structures involved in the passage of information across a chemical synapse.
Presynaptic terminal; postsynaptic membrane; synaptic cleft
Postsynaptic membrane; synaptic cleft; presynaptic terminal
Presynaptic terminal; synaptic cleft; postsynaptic membrane
Synaptic cleft; presynaptic terminal; postsynaptic membrane
Groups of related nerve cell bodies located outside of the central nervous system are called __________.
tracts
nerves
plexus
ganglia
A student observes a stained slide of brain tissue under the microscope. She notices a large number of neuron cell bodies and dendrites. What type of brain tissue is she looking at?
A ganglion
Gray matter
White matter
A cranial nerve
When threshold is reached, depolarization of the same magnitude occurs for all action potentials. If threshold is not reached, an action potential does not begin at all. This describes
saltatory conduction.
a graded response to stimuli.
the cable properties of axons.
the all-or-none law.
