Nervous System study guide
The brachial plexus supplies nerves that function to contract which of the following?
muscles of the arm and forearm
Gaps or interruptions in the myelin sheath are called
nodes of Ranvier.
An action potential
occurs when the local potential reaches threshold level.
A fracture of the cribriform plate might injure the ______ cranial nerve?
olfactory
Multiple sclerosis is a neurological disorder in which myelin sheaths in the CNS are destroyed. Which of the following neurological cells is being damaged in multiple sclerosis?
oligodendrocyte
When repolarization of a neuron is complete, the
original polarity of the neuron is restored.
Neurotransmitters are released from the
presynaptic terminal.
Spinal nerves exiting the cord from the level of L4 to about S4 form the
sacral plexus.
A stimulus that results in a local potential that does not reaches threshold level is called
subthreshold stimulus.
The junction between two neurons is a
synapes.
The most superficial meningeal layer is
the dura mater.
The plasma membrane of a neuron is more permeable to potassium ions because
there are more non-gated channels for K+ than Na+.
The motor (efferent) division of the peripheral nervous system
transmit impulses from the CNS to skeletal muscles.
Dentist anesthetize a portion of the _____ nerve to stop pain impulses from the teeth.
trigeminal
The motor root of a spinal nerve is also referred to as the
ventral root.
A stimulus either causes an action potential or it doesn't. This is called
a all or none response
Which of the following activities is not associated with the cerebrum?
acting as a control center of the autonomic nervous system.
The ceberal medulla
consists of many nerve tracts of white matter beneath the cerebral cortex.
Which of the following is NOT a function of the cerebellum?
control the heart rate
The sensory (afferent) division of the peripheral nervous system
conveys action potential to the CNS.
The gray matter on the outer surface of the cerebrum is called the
cortex
The peripheral nevrous system includes the
cranial nerves
The sensory foot of a spinal nerve is also referred to as
dorsal root.
There are ________ cervical spinal nerves.
eight
During brain surgery, the superior portion of the postcentral gyrus of a patient is stimulated. The patient is most likely to
feel pressure on his toes
Cell bodies of the peripheral nervous system are located in
ganglia
Which of the following substances must pass through the blood-brain barrier in order for neurons to survive?
glucose
Which portions of a reflex arc is most likely to be located entirely within the central nervous system?
interneurons
There are ___ pairs of cranial nerves and ___ pairs of spinal nerves
12; 31
Neurotransmitters is being released at a synapse. Which of the following occurs last?
An action potential is produced in the postsynaptic membrane.
Which of the following statements concerning the brainstem is true?
Damage to the brainstem is usually fatal.
Which of the following situations occurs in electrically excitable cells?
Depolarization causes voltage-gated sodium ion channels to open.
Dendrites
are the input part of the neuron.
The oculomotor nerve
adjusts pupil size to the level of lighting
Reflex arcs
are capable of receiving a stimulus and yielding a response.
The abducens nerve
are involved in eye movement
Neurons that have a single axon and a single dendrite are
bipolar.
Neurotransmitters
causes the production of action potentials in the postsynaptic membrane.
Which of the following is responsible for problem-solving skills?
central nervous system
Which of the following brain areas serves as the major control center of the autonomic nervous system and endocrine system?
hypothalamus
A local potential
increases or decreases in direct proportion to the stimulus strength.
The central nervous system
is the site for processing information.
The spinal cord
links the peripheral nervous system to the brain.
Which portion of the brainstem is continuous with the spinal cord?
medulla oblongata
The nervous system
monitors internal and external stimuli, transmits information in the form of action potentials, interprets or assesses information, maintains homeostasis.(all of these choices are correct).
The blood-brain barrier
protects neurons from toxic substances in the blood.
Reflexes function in
removing the body from painful stimuli, keeping the body from falling, maintaining blood pressure, maintaining blood CO2 levels. ( all of these choices are correct)
During depolarization of the plasma membrane,
sodium ions move rapidly into the cell.
Depolarization of the nerve cell membrane occurs when there is a rapid influx (inflow) of
sodium ions.
Which of the following is not a lobe of the cerebrum?
sphenoidal
The central nervous system includes the
spinal cord
Chemical synapes are characterized by
the release of neurotransmitter by the presynaptic terminal.
