What structure connects the right and left cerebral hemispheres?
Intermediate mass
Vermis
Septum pellucidum
Corpus callosum
answer
Corpus callosum
Correct. The corpus callosum is a large fiber tract of axons connecting the right cerebral hemisphere to the left cerebral hemisphere.
question
Which of the following areas form the central core of the brain?
Cerebellum
Thalamus
Epithalamus
Hypothalamus
answer
Thalamus
Correct. The thalamus is the central region of the diencephalon and forms the central core of the brain. The thalamus is enclosed by the cerebrum.
question
Where is the arbor vitae located?
Brain stem
Cerebrum
Diencephalon
Cerebellum
answer
Cerebellum
Correct. The white matter in the cerebellum has a branching arrangement that resembles a tree. This structure is named for its appearance. The term arbor vitae means "tree of life."
question
What part of the corpora quadrigemina is clearly observed in a midsagittal section?
Inferior colliculus
Superior colliculus
Optic chiasm
Corpus callosum
answer
Superior colliculus
Correct. The superior colliculus is clearly observed in the transverse fissure on the back of the midbrain. It is involved with directing eye movement.
question
Which region of the brain is necessary for consciousness?
Cerebrum
Diencephalon
Cerebellum
Brain stem
answer
Cerebrum
Correct. The cerebrum is involved in higher order functions such as consciousness, personality, and intellect.
Which of the following areas takes visual information from one side of the body and conveys it to the opposite side?
Optic nerve
Optic tract
Optic chiasm
Olfactory bulbs
answer
Optic chiasm
Correct. The optic chiasm is where the optic nerves cross midline, so that sensory information from one side of the body is processed on the opposite side of the brain.
question
Which of the following structures is not part of the central nervous system?
Optic tract
Mammillary body
Optic chiasm
Optic nerve
answer
Optic nerve
Correct. Nerves are bundles of axons found in the peripheral nervous system. The optic nerve is an extension of the brain, not part of the brain.
question
Which of the following glands can be observed on the ventral surface of the sheep brain?
Pituitary gland
Pineal gland
Mammillary body
Olfactory bulb
answer
Pituitary gland
Correct. The pituitary gland can be seen on the ventral surface of the brain. It can easily be removed with the meninges if care isn't taken to keep it attached.
question
Which of the following structures attach the pituitary gland to the brain?
Hypothalamus
Infundibulum
Optic chiasm
Pia mater
answer
Infundibulum
Correct. The infundibulum attaches the pituitary gland to the hypothalamus. It contains axons that originate in the hypothalamus and end in the posterior pituitary.
question
All three regions of the brain stem can be observed on the ventral surface of the brain.
False
True
answer
True
Correct. All 3 regions of the brain stem, the midbrain, pons, and medulla oblongata, can be observed on the ventral surface.
question
The cerebellum is present on the ventral surface of the sheep brain.
True
False
answer
False
Correct. The cerebellum is not a ventral structure. It is located on the dorsal surface of the brain.
question
Which of the following ventricles is found under the corpus callosum?
Third ventricle
Lateral ventricles
Fourth ventricle
Fornix
answer
Lateral ventricles
Correct. The lateral ventricles lie side by side under the corpus callosum, separated by the septum pellucidum.
question
Which passageway connects the third and fourth ventricles?
Central canal
Septum pellucidum
Interventricular foramen
Cerebral aqueduct
answer
Cerebral aqueduct
Correct. The cerebral aqueduct is the narrow passageway that connects the third and fourth ventricles. It can sometimes be observed on a midsagittal section.
question
Identify the passageway found in the spinal cord that is continuous with the ventricles.
Central canal
Cerebral aqueduct
Choroid plexus
Interventricular foramina
answer
Central canal
Correct. The central canal is the canal found in the spinal cord that originates off of the fourth ventricle.
question
Cerebrospinal fluid is produced within the ventricles.
True
False
answer
True
Correct. The choroid plexus produces cerebrospinal fluid. It is found in each of the ventricles.
question
The ventricles are all interconnected.
False
True
answer
True
Correct. Narrow passageways connect the ventricles together, so that cerebrospinal fluid flows freely inside the ventricular system.
question
Which of the following is NOT correct concerning nerves?
Nerves are collection of axons of either sensory or motor neurons but not both.
Nerves are analogous to tracts in the CNS.
Nerves do not contain cell bodies.
Nerves are covered by an outer sheath called the epineurium.
answer
Nerves are collection of axons of either sensory or motor neurons but not both.
question
Which connective tissue layer directly surrounds every axon in a nerve?
perineurium
epineurium
endomysium
endoneurium
answer
endoneurium
Within a nerve, each axon is surrounded by endoneurium, a delicate layer of loose connective tissue that also encloses the fiber's associated Schwann cells.
question
Which cranial nerve innervates most of the visceral organs?
accessory
vagus
hypoglossal
abducens
answer
vagus
The vagus nerve has many targets in the thoracic and abdominal cavities and innervates many of the visceral organs.
question
Which of the following cranial nerves carries only motor information?
optic
abducens
olfactory
trigeminal
answer
abducens
The abducens carries efferent (motor) signals to the extrinsic eye muscle that abducts the eye (turns it laterally).
question
The phrenic nerve is a branch from the __________.
brachial plexus
vagus nerve
cervical plexus
thoracic spinal cord
answer
cervical plexus
The phrenic nerve, which arises from the cervical plexus, supplies both motor and sensory fibers to the diaphragm, the main breathing muscle.
question
Hiccups could occur if there was irritation or damage to the ______.
dorsal rami of spinal nerves associated with the C3-C5 region of the spinal cord
afferent neurons of spinal nerves associated with the C3-C5 region of the spinal cord
cutaneous branches of rami associated with the C3-C5 region of the spinal cord
motor branches of ventral rami associated with the C3-C5 region of the spinal cord
answer
motor branches of ventral rami associated with the C3-C5 region of the spinal cord
The ventral rami of spinal nerves contain motor fibers that originate from neuron soma found in the spinal cord. These efferent pathways activate the contraction of skeletal muscle. The phrenic nerve branches from this region and innervates the skeletal muscle of the diaphragm.
question
The brachial plexus can be palpated at the lower lateral border of the sternocleidomastoid muscle. Injury to the brachial plexus could cause weakness or paralysis to all of the following EXCEPT the ______.
deltoid muscle
biceps brachii muscle
sternocleidomastoid muscle
muscles that flex the wrist and fingers
answer
sternocleidomastoid muscle
The sternocleidomastoid muscle is innervated by the accessory cranial nerve and branches of cervical spinal nerves C2 and C3.
question
In carpal tunnel syndrome, there may be tingling and numbness in the thumb due to compression of the ______.
thumb muscles
cutaneous branches of the median nerve
muscular branches of the posterior cord that supply the median nerve
None of the listed responses is correct.
answer
cutaneous branches of the median nerve
The median nerve cutaneous branch carries sensory input from the skin of the lateral 2/3rds of the hand, palm side and dorsum of fingers 2-3.
question
Damage to the ulnar nerve could result in the inability to ______.
supinate or pronate the forearm
flex the wrist
extend the forearm
All of the listed responses are correct.
answer
flex the wrist
One action of the flexor carpi ulnaris muscle is wrist flexion. This muscle is innervated by the ulnar nerve.
question
Which of the following lists the hierarchy of motor control from lowest to highest level of control?
segmental level, precommand level, projection level
projection level, precommand level, segmental level
segmental level, projection level, precommand level
precommand level, projection level, segmental level
answer
segmental level, projection level, precommand level
The hierarchy of motor control from lowest to highest level of control is segmental level, projection level, and precommand level.
question
Which of the following is NOT required for a reflex arc?
receptors
interneurons
sensory neurons
motor neurons
answer
interneurons
In many cases, the interneurons are the integration point for reflexes, but they are not necessary.
question
When removing a hot sheet of cookies from the oven, you feel heat coming through the pot holder. What mechanism momentarily overrides your reflexive action to immediately drop the hot cookie sheet?
modification of outgoing efferent signals by spinal cord gray matter interneurons
modulation of descending motor pathways by brainstem and cortex
temporary suppression of sensory input to the spinal reflex center
intervention by the limbic system to inhibit the fear of being burned
answer
modulation of descending motor pathways by brainstem and cortex
question
Which reflex is triggered when a stranger suddenly grasps your arm?
crossed-extensor reflex
plantar reflex
tendon reflex
stretch reflex
answer
crossed-extensor reflex
The grasped arm is withdrawn (via the flexor reflex) as the opposite arm pushes you away from the attacker (via crossed-extensor reflex). As in this scenario, the crossed-extensor reflex often accompanies the flexor reflex.
question
Which of the following is a way in which the somatic and autonomic nervous systems are similar?
Both systems share common effectors.
Both systems share common efferent pathways.
Both systems have ganglia in their motor pathways.
Both systems elicit the same target organ responses to their neurotransmitters.
None of the listed responses is correct.
answer
None of the listed responses is correct.
Each of the factors is different in the somatic and autonomic efferent pathways, respectively.
question
Which of the following is NOT an autonomic nervous system (ANS) function?
increasing heart rate
gland secretion
reflex of skeletal muscle
emptying the bladder
answer
reflex of skeletal muscle
The somatic nervous system stimulates skeletal muscle, whereas the ANS innervates cardiac muscle, smooth muscle, and glands.
question
Which of these activities is most likely driven by parasympathetic innervation?
sweating and dilating pupils
fight-or-flight responses
vigorous physical activity
resting and digesting
answer
resting and digesting
The parasympathetic division, sometimes called the "rest and digest" system, keeps body energy use as low as possible, even as it directs vital housekeeping activities like digesting food and eliminating feces and urine.
question
Once a preganglionic axon reaches a trunk ganglion, one of three things can happen to the axon. Which of the following is NOT one of these three things?
The axon can pass through the trunk ganglion and emerge from the sympathetic trunk without synapsing.
The axon can synapse with a ganglionic neuron in the same trunk ganglion.
The axon can course back into the spinal cord to synapse with preganglionic neurons in a different spinal segment.
The axon can ascend or descend the sympathetic trunk to synapse in another trunk ganglion.
answer
The axon can course back into the spinal cord to synapse with preganglionic neurons in a different spinal segment.
Preganglionic axons do not pass back into the spinal cord.
question
Unlike the sympathetic division, the parasympathetic division synapses with the adrenal medulla.
True
False
answer
False
The sympathetic division synapses at the adrenal medulla which enhances the sympathetic responses.
question
The sympathetic division innervates targets with nerves that all originate from the thoracolumbar region.
True
False
answer
True
The sympathetic division is also called the thoracolumbar division of the autonomic nervous system because the thoracic and upper lumbar spinal segments contain the cell bodies of all preganglionic sympathetic neurons.
question
Symptoms of autonomic neuropathy could include any EXCEPT which of the following?
diarrhea
constipation
abnormal stretch reflex responses
hyposecretion by sudoriferous glands
answer
abnormal stretch reflex responses
The stretch reflex is controlled by afferent sensory stretch receptors and somatic efferent motor neurons.
question
Which of the following target organs/systems is affected by the sympathetic nervous system but is NOT affected by the parasympathetic nervous system?
cellular metabolism
salivary glands
lungs
gallbladder
answer
cellular metabolism
Preganglionic sympathetic fibers stimulate the adrenal medulla to secrete epinephrine into the bloodstream during "fight-or-flight" situations (such as exercise). In turn, epinephrine increases cellular metabolism (metabolic rate).
question
Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)?
brain stem
frontal lobe of the cerebral cortex
reticular formation
hypothalamus
answer
hypothalamus
The hypothalamus stands at the top of the control hierarchy as the integrator of ANS activity. The limbic system communicates the hypothalamus, which is why emotions, like fear, affect the ANS. The reticular formation connects the hypothalamus to nuclei in the brainstem that cause the ANS outputs for some visceral organs as their output is regulated by the hypothalamus.
question
Which of the following is responsible for the overall integration of the autonomic nervous system (ANS)?
hypothalamus
cerebral cortex
brain stem
peripheral ganglia
answer
hypothalamus
The hypothalamus stands at the top of the control hierarchy as the integrator of ANS activity.
question
During meningitis, which of the following is the most likely to be a direct source of pathogens that may spread to the brain?
pia mater
arachnoid mater
dura mater
arachnoid villi
answer
pia mater
The pia mater is meningeal layer closest to the brain.
question
Which type of glial cells are shown in this figure?
astrocytes
microglia
oligodendrocytes
ependymal cells
answer
ependymal cells
Specialized ependymal cells participate in the filtration, absorption, and secretory processes that create cerebrospinal fluid.
Manufacture of fluid within brain ventricles.
question
What CNS-associated structure is illustrated in this figure?
hypothalamus
choroid plexus
cerebral aqueduct
arachnoid villus
answer
choroid plexus
Manufacture of fluid within brain ventricles.
question
The middle primary brain vesicle, the mesencephalon, gives rise to which adult brain structure?
cerebrum
midbrain
medulla oblongata
diencephalon
answer
midbrain
The term mesencephalon means "midbrain." As it develops from a primary brain vesicle to a secondary brain vesicle and finally an adult brain structure, it retains its name--the midbrain. Each of the other two primary brain vesicles divides to give rise to new secondary brain vesicles and adult brain structures (with new names). Note that encephalo- means "brain."
question
After Joe has a stroke, his doctor asks Joe to touch his right pointer finger to his chin—but Joe is unable to move his right hand. However, when the doctor stimulates Joe's pointer finger with a painful stimulus, Joe's muscles quickly move his hand away from the stimulus. The doctor concludes that ______.
the stroke caused damage to Joe's frontal eye field which interfered with his effort to touch his chin
the stroke caused damage to Joe's right primary motor cortex
the stroke caused damage to Joe's right premotor cortex
based on the doctor's observations, none of the listed answers are correct conclusions
answer
based on the doctor's observations, none of the listed answers are correct conclusions
Review central nervous system control of voluntary skeletal muscle contractions and compare it to reflex arc activation.
question
A patient reports that she has become completely deaf—she can't hear anything. Thorough tests on her ears indicate that her ears have not been damaged. Additional tests reveal that her deafness has been caused by damage to her ______.
primary somatosensory cortex
auditory association area
somatosensory association cortex
None of the listed responses is correct.
answer
None of the listed responses is correct.
Review the different sensory cortices of the parietal and temporal lobes of the brain.
question
At age 79, Mrs. X is diagnosed with a disorder that severely impairs her logical judgment. Medical imaging techniques show that this has been most likely caused by brain damage in a ______.
parietal lobe
frontal lobe
temporal lobe
premotor cortex
answer
The frontal lobe has areas that control voluntary motor functions, mood, smell, and social judgment.
question
What is the designation of the area at D?
primary olfactory cortex
primary visual cortex
visual association area
multimodal association area
answer
primary visual cortex
The primary visual cortex receives sensory input from the eye via the optic nerves, thalamus, and optic radiations.
Lateral view of left cerebrum with selected functional areas highlighted.
question
Region A includes which of the following?
prefrontal cortex
primary motor cortex
primary somatosensory cortex
Broca's area
answer
prefrontal cortex
The prefrontal cortex is located in the anterior region of the frontal lobe.
question
The groove indicated by C is the __________.
longitudinal fissure
lateral sulcus
central sulcus
transverse fissure
answer
central sulcus
The central sulcus is the shallow groove that separates the frontal and parietal lobes.
question
The cortical regions indicated by E are involved in what functions?
the storage of motor patterns for skilled movements of skeletal muscles
the production and interpretation of language
They are the control centers for homeostatic and endocrine functions.
the generation of emotional responses
answer
the production and interpretation of language
Regions indicated by E include Broca's area in the frontal lobe and Wernicke's area in the temporal lobe.
question
The letter A in the figure indicates which of the following structures?
cerebral nuclei
lateral ventricles
thalamus
hypothalamus
answer
thalamus
The letter A indicates the thalamus. Remember that the thalamus is composed of left and right bodies.
question
The neural fibers connecting structure A to the cerebral cortex can be described by which of the following?
lower motor neurons
upper motor neurons
first-order sensory neurons
third-order sensory neurons
answer
Third-order sensory neurons relay ascending information from the thalamus to specific sensory areas of the cortex.
question
What structure(s) is/are indicated by B?
association fibers
lateral ventricles
pyramidal tracts
corpus callosum
answer
corpus callosum
The corpus callosum is the most prominent example of tracts that connect the left and right cerebral hemispheres.
question
Classify a fiber tract that communicates between the left prefrontal lobe and the left parietal lobe.
association
commissural fibers
projection
answer
Association fibers communicate between gyri in the same cerebral hemisphere.
question
Which part of the brain is the "executive suite" that controls almost all brain activity?
cerebellum
diencephalon
brain stem
cerebral cortex
answer
cerebral cortex
The cerebral cortex is the "executive suite" of the nervous system, where most of our higher-level decision making occurs. It enables us to be aware of ourselves and our sensations, communicate, remember, understand, and initiate voluntary movements.
question
Which of the following is true of the cerebral hemispheres of the human brain?
The cerebral hemispheres account for about 83% of total brain mass.
The longitudinal fissure separates the cerebral hemispheres from the cerebellum.
Nearly the entire surface of the cerebral hemispheres is marked by shallow grooves called gyri.
Nearly the entire surface of the cerebral hemispheres is marked by elevated ridges called sulci.
answer
The cerebral hemispheres account for about 83% of total brain mass.
The cerebral hemispheres, which form the superior part of the brain, account for about 83% of total brain mass.
question
Which of the following is NOT a correctly matched pair?
gray matter: location of brain nuclei
spinal cord: inner gray matter
gray matter: myelinated axons
superficial in the brain: gray matter
answer
gray matter: myelinated axons
Gray matter is indicative of unmyelinated axons and cell bodies in the CNS.
question
Which motor area both has a homunculus and has descending projection fibers?
primary motor cortex
Broca's area
frontal eye fields
premotor cortex
answer
primary motor cortex
The primary motor cortex has projections for the entire human body map, or homunculus. Axons from the primary motor cortex project from the frontal lobe to the spinal cord.
question
In general, a primary sensory cortex breaks down sensory input into component parts, while an association cortex makes sense of sensory inputs.
True
False
answer
True
The primary sensory cortex receives sensory inputs in their cruder forms, while the association cortex helps you understand what the sensory input means.
question
Which of the following is correctly matched?
gustatory cortex; sense of hearing
vestibular cortex; pattern recognition
posterior association area: understand balance
limbic association area: sense of danger
answer
limbic association area: sense of danger
The limbic association area is part of the limbic system, which control our emotions and fears.
question
The term cerebral dominance designates the hemisphere that is dominant for language.
True
False
answer
True
One cerebral hemisphere or the other "dominates" each of the brain's tasks, and the term cerebral dominance designates the hemisphere that is dominant for language. In most people (about 90%), the left hemisphere has greater control over language abilities, math, and logic.
question
Which of the following hypothalamic control centers would you predict is the LEAST important for survival?
suprachiasmatic nucleus
autonomic control center
temperature control center
thirst center
answer
suprachiasmatic nucleus
This area of the hypothalamus is important in determining the circadian rhythm that sets our sleep-wake cycles.
question
This area of the hypothalamus is important in determining the circadian rhythm that sets our sleep-wake cycles.
mesencephalon
hypothalamus
pons
thalamus
answer
thalamus
Afferent impulses from all senses and all parts of the body converge on the thalamus and synapse with at least one of its nuclei. The thalamus-- which sorts out and edits these afferent signals before relaying them to the appropriate cortical areas--is considered the gateway to the cerebral cortex. In summary, the thalamus plays a key role in mediating sensation, motor activities, cortical arousal, learning, and memory.
question
Which of the following best describes the hypothalamus?
somatic motor control center
visceral control center of the body
gateway to the cerebellum
relay station for the special senses
answer
visceral control center of the body
The hypothalamus is the main visceral control center of the body and is vitally important to overall body homeostasis. Its chief homeostatic roles include controlling the autonomic nervous system; controlling endocrine system function; regulating the sleep-wake cycle, body temperature, hunger, and thirst; and initiating physical responses to emotions.
question
Which of the following is NOT a diencephalon component?
thalamus
superior colliculus
hypothalamus
pineal gland
answer
The superior colliculus is at the inferior border of the diencephalon, located in the midbrain region of the brain stem.
question
The hypothalamus is the area where afferent impulses from all senses and all parts of the body are sorted out and then relayed to the appropriate area of the sensory cortex.
True
False
answer
False
Afferent impulses from all senses and all parts of the body converge on the thalamus (not the hypothalamus) and synapse with at least one of its nuclei. The thalamus--which sorts out and "edits" these afferent signals before relaying them to the appropriate cortical areas--is considered to be the gateway to the cerebral cortex.
question
Which of the following is NOT a function of the hypothalamus?
regulate food intake
regulate emotional responses
regulate body temperature
regulate the thalamus
answer
regulate the thalamus
The hypothalamus does not regulate the thalamus.
question
Which of the following regions of the brain stem serves as a bridge between the brain stem and the cerebellum?
midbrain
thalamus
pons
medulla oblongata
answer
pons
The pons is the point at which all information entering or exiting the cerebellum is collected. Descending motor input and ascending sensory input that feed the cerebellum and all cerebellar output enter or exit the cerebellum through several cerebellar peduncles located in the pons.
question
Which part of the brain processes inputs received from the cerebral motor cortex, brain stem nuclei, and various sensory receptors, and then uses this information to coordinate balance, posture, and somatic movement problems?
diencephalon
cerebellum
thalamus
pons
answer
cerebellum
By processing and interpreting impulses from the motor cortex and brain stem nuclei, as well as sensory pathways, the cerebellum provides the precise timing and appropriate patterns of skeletal muscle contraction for the smooth, coordinated movements and agility needed for daily living (e.g., driving, typing, and tying our shoes). It also plays a poorly understood role in cognition. Cerebellar activity occurs subconsciously (we are not aware of it).
question
Which functional area of the brain is responsible for our level of awareness and alertness?
reticular activating system
Broca's area
frontal eye fields
limbic system
answer
reticular activating system
The reticular activating system is responsive to our sensory input and controls alertness to these sensory inputs and our awareness and responsiveness to our external (and internal) environment.
question
Suppose a patient produced more fluid in the structure shown in the figure than could be distributed throughout the ventricles and extracellular fluid. What condition would result?
anencephaly
Alzheimer's disease
hydrocephalus
cerebral palsy
answer
Hydrocephalus is the accumulation of fluid in the ventricles, which puts pressure on the brain.
question
Where is the illustrated structure located?
in each ventricle
within the subarachnoid space
in the central canal
within the superior sagittal sinus
answer
in each ventricle
Cerebrospinal fluid is produced within the choroid plexus located within each ventricle.
question
Which protective covering of the brain provides passageways for cerebrospinal fluid (CSF) to drain into the superior sagittal sinus?
membranous part of the dura mater
arachnoid mater
pia mater
periosteal part of the dura mater
answer
arachnoid mater
The subarachnoid space is filled with CSF. Knoblike projections of the arachnoid mater, called arachnoid villi, protrude superiorly through the dura mater and into the superior sagittal sinus. These villi provide a passageway for CSF to leave the subarachnoid space and enter the venous blood of the sinus.
question
Which of the meninges is a delicate connective tissue membrane that clings tightly to the brain like cellophane wrap following its every convolution?
arachnoid mater
meningeal layer of the dura mater
periosteal layer of the dura mater
pia mater
answer
pia mater
The pia mater, meaning "gentle mother," is composed of delicate connective tissue and is richly invested with tiny blood vessels. It is the only meninx that clings tightly to the brain, like cellophane wrap, following its every convolution.
question
__________ is a progressive degenerative disease of the basal nuclei that affects the dopamine-secreting pathways.
Parkinson's disease
Huntington's disease
Alzheimer's disease
mad cow disease
answer
Parkinson's disease
Parkinson's disease results from a degeneration of the dopamine-releasing neurons of the substantia nigra (of the midbrain). As those neurons deteriorate, the dopamine-deprived basal nuclei they target become overactive. Afflicted individuals have a persistent tremor at rest, a forward-bent walking posture and shuffling gait, and a stiff facial expression. They are slow with initiating and executing movement.
question
What part of the spinal cord represents an increase in cell body mass for upper limb control?
lumbar enlargement
cervical enlargement
cauda equina
conus medullaris
answer
cervical enlargement
The spinal cord has an obvious enlargement in the cervical region, called the cervical enlargement, where the cell bodies controlling the upper limbs arise.
question
Which of the following statements is correct concerning the spinal cord?
Damage to sensory tracts in the spinal cord leads to paralysis.
Spinal nerves have mixed motor and sensory function.
Just like the cerebrum, the gray matter is found on the superficial surfaces.
The white matter contains cell bodies for spinal nuclei.
answer
Spinal nerves have mixed motor and sensory function.
The ventral roots carry motor commands out of the spinal cord. The dorsal roots carry sensory information into the spinal cord. The spinal nerves represent a fusion of these two elements.
question
The fiber tracts indicated by the letter C will terminate in the __________.
sensory cortex
cerebellum
thalamus
medulla oblongata
answer
cerebellum
The letter C indicates the spinocerebellar pathways.
question
Which of the following describes the nerve fibers indicated by the letter A?
first-order sensory neurons
second-order sensory neurons
third-order sensory neurons
answer
first-order sensory neurons
First-order sensory neurons transmit sensory information from receptors to the spinal cord.
question
Where are the cell bodies of the sensory neurons at A located?
in the posterior horn of the spinal cord
in the medulla oblongata
in the thalamus
in the dorsal root ganglion
answer
in the dorsal root ganglion
All sensory neurons, including those of the autonomic nervous system, are found in the dorsal root ganglion.
question
What function is most closely associated with the spinal cord tract indicated by the letter C?
What function is most closely associated with the spinal cord tract indicated by the letter C?
Several examples of ascending spinal cord tracts.
initiation of smooth muscle movements
initiation of skeletal muscle movements
response to skeletal muscle pain
coordination of skeletal muscle movements
answer
coordination of skeletal muscle movements
These tracts carry appropriate sensory information, such as the degree of muscle stretch, to the brain such that it can calculate skeletal muscle movements that allow for coordinated responses and the maintenance of balance.
question
The fiber tracts indicated by the letter D will terminate in the __________.
thalamus
primary somatosensory cortex
cerebral nuclei
primary motor cortex
answer
thalamus
The spinothalamic tracts indicated by D carry somatosensory information and terminate in the thalamus. Specific information will then be relayed to the appropriate area of the somatosensory cortex by third-order sensory neurons.
question
Most of the descending fibers indicated in this figure cross over (decussate) to the opposite side of the body in which of the following?
Most of the descending fibers indicated in this figure cross over (decussate) to the opposite side of the body in which of the following?
Pathways of motor neurons through the upper CNS.
cerebellum
peripheral nervous system
medulla oblongata
thalamus
answer
medulla oblongata
Many descending fibers cross over to the contralateral side of the nervous system within the decussation of pyramids in the medulla.
question
The descending fibers in the figure provide for which of the following functions?
The descending fibers in the figure provide for which of the following functions?
Pathways of motor neurons through the upper CNS.
conscious awareness of sensory information
involuntary control of cardiac muscle
voluntary control of skeletal muscle
involuntary control of smooth muscle
answer
voluntary control of skeletal muscle
Motor pathways originating in the primary motor cortex allow for the conscious control of skeletal muscle.
question
Which of the following is NOT a feature of the major spinal cord tracts (pathways)?
relay
somatotopy
decussation
memory
answer
Memory is a function of the brain (not the spinal cord).
question
Select the true statement regarding first-order neurons.
.
First-order neuron cell bodies reside in a ganglion.
First-order neurons descend with motor commands.
First-order neurons usually ascend directly to the thalamus.
First-order neurons originate in the CNS.
answer
First-order neuron cell bodies reside in a ganglion.
First-order neurons, whose cell bodies reside in a ganglion (dorsal root or cranial), conduct impulses from the cutaneous receptors of the skin and from proprioceptors to the spinal cord or brain stem, where they synapse with second-order neurons.
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