Nervous System (PNS) Flashcards
(50 cards)
A bundle of neuron fibers found outside the cns
Nerve
Nerve Structure
- Endoneurium- Delicate (fiber)
- Perineurium- coarse (group of fibers)
- Epineruium- Tough (fascicles)
Nerve classification according to the direction of impulse
Afferent (Sensory) Nerves- Carries sensation
Efferent (Motor) Nerves - Carries motor fibers
Mixed Nerves- Both sensation and motor fibers
ALL SPINAL NERVES ARE MIXED
Supplies the head and neck except vagus nerves that extends to thoracic and abdominal cavities.
Cranial Nerves
How many cranial nerves in total?
12 pairs/ 24 total
Most cranial nerves are mixed, EXCEPT?
Optic, olfactory, vestibulocochlear nerves (SENSATION ONLY)
Give the cranial nerve and function
1 Olfactory (Sensation)
2 Optic Nerve (Sensation)
3 Oculomotor (Motor)
4 Trochlear Nerve (Motor)
5 Trigeminal (Both)
6 Abducent (Motor)
7 Facial (Both)
8 Acoustic Nerve (Sensory)
9 Glossopharyngeal (Both)
9 Vagus Nerve (Both)
11 Accessory Nerve (Motor)
12 Hypoglossal Nerve (Motor)
All nerves are located in the brainstem except?
CN1 (Olfactory) - Telencephalon
CN2 (Optic) - Diencephalon
LOCATED IN THE CEREBRUM
Location of the cranial nerve in the brainstem
Midbrain (CN3, 4)
Pons (CN 5, 6,7 ,8)
Medulla Oblongata (CN 7,8,9,10,11,12)
Sense of smell. To test is to allow patient to sniff aromatic substances
Cranial Nerve 1 - Olfactory
Vision. Tests to conduct will be snellen’s chart, confrontation test, ishihara, tonometry, retinoscopy, pupillary light reflex.
Cranial Nerve 2 (Optic Nerve)
Lesions in cranial nerve 2
- Myopia
- Hyperopia
Nerve supply for the muscles that direct the eyeball. Controls the cardinal gaze
Cranial Nerve 3, 4, 6
Give the muscles of Cranial Nerve 3, 4 ,6
Cranial Nerve 4- Superior Oblique (Downward and middle motion of eye)
Cranial Nerve 6 - Lateral Rectus
Cranial Nerve 3- Superior, Medial, Inferior Rectus and inferior oblique (Constricting of pupil)
Lesion in Cranial Nerve 2 and 3 will lead to an unequal pupil size named
Anisocoria
Largest cranial nerve because of its sensory distribution.
Motor: muscle for mastication TIME ( Temporalis, Internal Pyterygoid, Masseter, External Ptyerygoid)
Sensory: Sensation to face. General sensation in the anterior 2/3 or the tongue (pain and temp)
Reflex: Corneal Reflex
Testing: Sensory and muscle testing
Cranial Nerve 5: Trigeminal Nerve
Divisions in Facial Sensation of Tregeminal Nerve (5)
- Opthalmic Division (Afferent of Corneal Reflex)
- Maxillary Division
- Mandibular Division
Motor function is facial expression
Sensory: Taste for the anterior 2/3 of the tongue.
Autonomic: salivation and lacrima formation
Efferent of Corneal Reflex
Cranial Nerve 7 (Facial Nerve)
Lesion in CN7
Peripheral Lesion- Bell’s Palsy (cannot raise eyebrow)
Central Lesion- Stroke (can raise eyebrow)
Has 2 part function; 1 is vestibular (balance) lesion will result to disequilibrium 2. Cochlea (hearing) lession is deafness
Test - Tuning fork test
(Weber- Lateralization of hearing)
( Rinne- Compares air conduction)
Acoustic Nerve (CN8)
Sensory: Taste and general sensation to the posterior 1/3 of the tongue. Autonomic: Parotid gland (monitors carotid and body sinus)
Afferent of gag reflex
Glossopharyngeal Nerve (CN9)
Motor: muscle of pharynx and larynx. (Phonation)
Sensory: Gives sensation to the skin of pinna of the external of the ear and sensation to pharynx, larynx, and epiglottis
Autonomic: Innervates visceral organs of thorax and abdomen
Efferent of gag reflex in CN9
Vagus Nerve (CN10)
Has 2 part function
1. Cranial : supplies the pharyngeal muscle.
2. Spinal: Supplies SCM and trapezius
Cranial Nerve 11 (Accessory Nerve)
Supplies tongue muscles.
Cranial Nerve 12 (Hypoglossal Nerve)
