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