peripheral nervous system
A bit of dust blows into and touches the cornea of the eye. Which of the following is likely to happen?
Stimulation of the ophthalmic division of the trigeminal nerve (V) will cause blinking. Submit
Which of the following cranial nerves carries only motor information?
The abducens carries efferent (motor) signals to the extrinsic eye muscle that abducts the eye (turns it laterally).
You are closely observing a patient admitted to the ICU for head trauma. During his last examination, the patient demonstrated normal gaze. Now the patient's left eye is deviated inward, and he complains of double vision. What is your concern?
The abducens nerve (cranial nerve VI) is not functioning, possibly because of increased pressure inside the cranium. This is a crucial diagnostic clue.
Which of the following symptoms would you expect a person suffering from abducens nerve paralysis to display?
The patient's eye would have a tendency to rotate medially.
Which cranial nerve innervates most of the visceral organs?
The vagus nerve has many targets in the thoracic and abdominal cavities and innervates many of the visceral organs.
Which of the cranial nerves is responsible for regulating and balancing the effects of the sympathetic nervous system on many organs of the body?
The vagus nerves are the only cranial nerves to extend beyond the head and neck into the trunk. These nerves are responsible for the many of the parasympathetic, or "rest and digest" activities of the autonomic nervous system, as well as transmitting sensory information from viscera to the brain.
The cranial nerve that emerges from the pons and serves the motor and proprioceptive functions of the eyeball is the ________.
abducens (cranial nerve 6, cn6)
the eye cannot be moved laterally. at rest, the eyeball rotates medially
abducens nerve paralysis
controls the extrinsic eye muscle that abducts the eyeball (turns it laterally)
abducens nerve, cranial nerve 6, cn6
results from practice and repetition, substantial time and effort required to make it feel natural
acquired/learned reflex
the other ten pairs of cranial nerves are
associated with the brain stem
c5-t1, axilary, musculocutaneous, median, radial, ulnar nerves
brachial plexus
The majority of cranial nerves arise from this brain region.
brain stem
Bell's palsy is characterized
by paralysis of the facial nerves
major spinal nerve plexuses
cervical brachial lumbar sacral
phrenic nerve, c1-c4, some c5
cervical plexus
respond to chemical in solutions
chemoreceptors
A fracture of the ethmoid bone could result in damage to which cranial nerve?
cn1, olfactory
Which cranial nerve group is collectively responsible for the special senses?
cranial nerves I, II, VIII, and IX (olfactory, optic, vestibulocochlear, and glossopharyngeal)
maintaining balance, ipsilateral withdrawal reflex and contralateral extensor reflex
crossed-extensor reflexes
results in bell's palsy, which is characterized by paralysis of facial muscles on the affected side and partial loss of taste sensation
damage to the facial nerves
leads to drooping of the eye and an eye that deviates laterally at rest
damage to the oculomotor nerve
results in double vision and impairs the ability to rotate the eye laterally
damage to the trochlear nerve
muscle fiber or gland cell that responds to the efferent impulses (by contracting or secreting)
effector
lesion/damage to this nerve will lead to bell's palsy
facial nerve, cranial nerve 7, cn7
this cranial nerve innervates muscles of facial expression
facial nerve, cranial nerve 7, cn7
A patient has lost the ability to taste food. Which nerve may have been damaged?
facial nerves (cn7)
Drooping of the upper eyelid, and double vision are potential symptoms of damage to the olfactory nerve.
false
mechanism by which a neuron/circuit is tuned to one feature/property of a stimulus in preference to another; usually involves interplay of several stimulus features
feature abstraction
this nerve provides motor, parasympathetic, and sensory information to your nose and throat and helps raise part of the throat, enabling swallowing
glossopharyngeal nerve, cranial nerve nine, cranial nerve ix, cn9
precommand level
highest in motor hierarchy cerebellum and basal nuclei programs and instructions (modified by feedback)
damage to this nerve would cause difficulty in speech and swallowing, but now effect on visceral organs
hypoglossal (cn12)
simple arcs: monosynaptic reflex complex arcs: involve multiple synapses with chains of interneurons, polysynaptic reflex
integration center
inborn reflex, unlearned, unpremeditated, involuntary, built into our neural anatomy, keeps us alive
intrinsic reflex
segmental level
lowest level on motor hierarchy spinal cord contains central pattern generators (cpgs)
L1, L4, femoral and obturator nerves
lumbar plexus
how intense the stimulation is; increases stimulus intensity increases because of frequency coding
magnitude estimation
projection level
middle-level motor hierarchy motor cortex (pyramidal pathways) and brain stem nuclei (vestibular, red, reticular formation) conveys instruction to spinal cord motor neurons and sends a copy of that information to higher levels)
conducts efferent impulses from the integration center to an effector organ
motor neuron
respond to potentially damaging stimuli that result in pain
nociceptors
types of receptors
nociceptors, thermoreceptors, photoreceptors, and chemoreceptors
Mixed cranial nerves containing both motor and sensory fibers include all EXCEPT which of the following?
olfactory (cn1)
A patient is suffering from the inability to distinguish various types of odors. This patient may have damage to which of the following?
olfactory nerve (cn1)
sensory nerve of vision
optic nerve, cranial nerve 2, cn2
the ability to take in the scene and recognize familiar patters, significant patterns, or unfamiliar patterns
pattern recognition
the ability to detect a stimulus has occurred; the simplest level of perception
perceptual detection
list the major factors of sensory perception
perceptual detection, magnitude estimation, spatial discrimination, feature abstraction, quality discrimination, and pattern recognition
respond to light
photoreceptors
innervated muscles and skin of the perineum, and helps stimulate erection and control urination
pudendal nerve
the ability to differentiate the submodalities of a particular sensation; each sensory modality has several submodalities
quality discrimination
site of stimulus action
receptor
sciatic (composed of tibial and common fibular nerves); l4-s4
sacral plexus
the thickest and longest nerve in the body supplies the entire lower limb except for the anteromedial thigh, transection to this results in an almost entirely useless leg
sciatic nerve
largest branch of the sacral plexus
sciatic nerve (L4-S3)
motor hierarchy, lowest to highest
segmental level projection level precommand level
transmits afferent impulses to the central nervous system
sensory neuron
reflexes that activate skeletal muscle
somatic reflexes
allows us to identify the site or pattern of stimulation
spatial discrimination
cause muscle contraction in response to increased muscle length (stretch)
stretch reflexes
elicited by gentle cutaneous stimulation, clinically important, known as abdominal and plantar
superficial reflexes
muscles relax and lengthen in response to tension
tendon reflexes
destruction/damage to this nerve results in an eye that cannot move laterally
the abducens nerve, cn6
considered an accessory to the vagus, formerly called spinal accessory nerve
the accessory nerve, cranial nerve xi, cranial nerve 11, cn11
As a cook chops red onions he begins to tear up due to activation of the lacrimal gland. Which of the following nerves provided the stimulus?
the facial nercve (cn7)
the first two pairs of cranial nerves attach to
the forebrain
this cranial nerve innervates some tongue-moving muscles
the hypoglossal nerve, cranial nerve xii, cranial nerve 12, cn12
supplies four of the six eye muscles
the oculomotor nerve; cranial nerve 3 (CN3)
responsible for the sense of smell
the olfactory nerve; cranial nerve i, cn1
lesions of this nerve will lead to loss of sensation on that side of the face
the trigeminal nerve, cn5
what nerve means wanderer
the vagus nerve
A doctor asks her patient to follow the motion of her finger as she moves it up and down, left and right. Which of the following cranial nerves is NOT being tested?
the vestibulocochlear nerve (cranial nerve VIII, cn8)
lesion of this cranial nerve will lead to deafness and dizziness
the vestibulocochlear nerve (cranial nerve viii, cn8)
respond to temperature changes
thermoreceptors
how are the twelve nerve pairs named
they are named after the structures they serve to function and are numbered from most rostral (front) to most caudal (back)
supplies sensory fibers to the face and motor divers to the chewing muscles
trigeminal nerve, cranial nerve 5, cn5
damage to this nerve would keep the eye from moving inferolaterally
trochlear nerve
innervates the superior oblique muscle
trochlear nerve
innervates an extrinsic eye muscle that loops through a pulley-shaped ligament in the orbit
trochlear nerve, cranial nerve 4, cn4
The second cranial nerve forms a chiasma at the base of the brain for partial crossover of neural fibers.
true
how many nerve pairs are associated with the brain
twelve
nerve involved in movement of the digestive tract
vagus (cn10)
longest cranial nerve
vagus nerve
what cranial nerve extends beyond the head and neck to the thorax and abdomen
vagus nerve, cranial nerve x, cn10
this cranial nerve extends past the head and neck and innervates the thorax and abdomen
vagus, cranial nerve 10, cn10
Problems in balance may follow trauma to which nerve?
vestibulocochlear (cn8)
a sensory nerve for hearing and balance
vestibulocochlear nerve, cranial nerve viii, cranial nerve 8, cn8
autonomic, they activate visceral effectors such as smooth/cardiac muscles/glands
visceral reflexes