Term | Definition |
sensory receptor definition | a nerve ending that responds to a stimulus in the internal or external environment of an organism (ie. pain). In response to stimuli the sensory receptor initiates sensory transduction by creating action potentials. |
major types of sensory receptors (8) | baroreceptor (pressure), chemoreceptor (chemicals), mechanoreceptor (touch, sound, etc.), nociceptor (pain), osmoreceptor (diff. in osmolality), photoreceptor (light), proprioceptor (body in env.), thermoreceptor (temp.), |
The PNS connects the ___ with ___. | CNS, organs |
Cranial nerves emerge... | directly from the brain: CNI and CNII emerge from the cerebrum; remaining 10 emerge from brainstem. |
Cranial nerves: sensory | convey info only from PNS to CNS, |
Cranial nerves: motor | one particular cranial nerve acts on one particular muscle |
Cranial nerves: mixed | contains both sensory and motor components |
All cranial nerves, except the Vagus nerve (CN X), deal exclusively with... | the muscles of the jaw, face, tongue, neck, pharynx and larynx. |
CNI | Olfactory (sensory)- innervation: the nasal epithelium; function: smell; pathology: anosmia (loss of sense of sense of smell) |
CNII | Optic (sensory)- innervation: retina; function: vision; pathology: blindness |
CNIII | Oculomotor (motor)- innervation: all eye muscles except those supplied by CN IV and CN VI; function: eye movement, pupil constriction, eyelid open; pathology: oculomotor nerve palsy (eyelid drooping) |
CNIV | Trochlear (motor)- innervation: superior oblique muscle; function: eye movement; pathology: trochlear nerve palsy (superior oblique is weak or paralyzed-> double vision or vertical diplopia) |
CNV | Trigeminal (mixed)- innervation: (s) face, eyes, scalp, nasal mucosa, teeth, anterior 2/3 of tongue (m) muscles of jaw, velum & middle ear; function: facial sensation, mastication; pathology: loss of facial sensation, weakness/loss of mastication |
CNVI | Abducens (motor)- innervation: lateral rectus muscle; function: contract lateral rectus muscle to abduct (turn out) eye; pathology: abducens (abduction) nerve palsy->horizontal diplopia |
CNVII (type and innervation) | Facial (mixed)- Innervation:(s)taste from anterior 2/3 of tongue, oropharynx, auricle (m)all muscles of facial exp., salivary glands, lacrimal glands, stapedius muscle of M.E., digastric and stylohyoid |
CNVIII | Vestibulocochlear (sensory)- innervation: cochlea, utricle, saccule, & semicircular canals; function: hearing & balance; pathology: deafness & vertigo |
CNIX | Glossopharyngeal (mixed)- I.:(s)posterior 1/3 of tongue, velum, pharynx, tonsils (m)stylopharyngeus, muscle and parotid (salivary) gland; F.:taste, salivation, control of pharyngeal muscles; P.: anesthesia of dorsal 1/3 tongue, taste loss, gag reflex loss |
CNX (function and pathology) | Vagus (mixed)- F.: swallowing, talking, cardiac, gastrointestinal tract, respiration, taste (conveys sensory info about state of body's organs) P.: includes dysphagia, hoarseness of voice, loss of cough reflex, loss of taste (hard palate) |
CNXI | Accessory (motor)-I.: pharyngeal muscles and velum muscle, neck muscles: trapezius (shrugging)& sternocleidomastoid (rotates head); F.: control of pharyngeal & palate muscles, movement of neck & shoulder; P.: head rotation/shrugging weakness |
CNXII | Hypglossal (motor)-I.: intrinsic and extrinsic muscles of the tongue; F.: tongue movement; P.: atrophy, deviation, protrusion, &/or fasciculation (twitching) of tongue muscles |
Describe the ethmoid bone | Full of very tiny holes so that nerve endings can get through, crossing over the cribriform plate and spreading over the mucosa. Smells reach these fibers, which then send signals to brain. Only place where nerve endings can regenerate. |
vestibular schwannoma | tumor of vestibular portion of CN VIII->ipsilateral sensorineural hearing loss + vertigo |
pathological nystagmus | involuntary eye movement characterized by smooth pursuit in one direction and saccadic movement in the other |
3 major branches of the trigeminal nerve | ophthalmic nerve (s), maxillary nerve (s), and mandibular nerve (b) |
ophthalmic nerve | scalp, forehead, upper eyelid, cornea, nose |
maxillary nerve | lower eyelid, cheek, nares, upper lip, upper teeth and gum, palate |
mandibular nerve | lower teeth and gum, chin, jaw, anterior 2/3 of tongue |
muscles involved in mastication | masseter, temporalis, medial pterygoid, lateral pterygoid, digastric, mylohyoid, eustachian tube/velum: tensor veli palatini, & middle ear: tensor tympani |
CNV lesions (sensory) | loss of tactile sensation along one or more branches (e.g. anterior 2/3 of tongue, tooth/gum); trigeminal neuralgia |
trigeminal neuralgia | severe sharp shooting pain along one or all branches of CN V |
CNV lesions (motor) | paralysis of muscles on one side of jaw. Jaw deviates to side of lesion when closes (due to action of pterygoids on normal side) |
CNVII (function and pathology) | Facial (mixed)-Function: facial exp., taste, salivation, lacrimation; Pathology:facial paralysis, loss of taste, dry mouth, loss of tears |
5 branches of the facial nerve | temporal, zygomatic, buccal, mandibular, cervical (in descending order) |
CNVII lesions | commands sent to the upper part of the face receives bilateral innervation from UMN (upper motor neuronal) tracts BUT portion controlling the lower part of face receives contralateral innervation.(UMN lesions affect lower side of face; LMN entire face) |
CNX (Innervation: s) | Vagus (mixed)-(s)taste, major sensory nerve (head, neck, chest, abdomen) |
CNX (Innervation: m) | Vagus (mixed)-(m)majority of viscera (heart, respiration, digestion), pharyngeal constrictor muscles, palatal muscles, intrinsic musculature of the larynx (e.g. cricothyroid muscle involved in pitch changes) |
CNX lesion of pharyngeal branch | hyper nasality, nasal regurgitation, chocking when drinking fluid, loss of gag reflex, dysphagia (difficulty in swallowing), & paralysis of pharyngeal musculature. Uvula deviates away from side of lesion. |
CNX lesion of laryngeal branch | flaccid/paralysis of vocal folds, hoarse/breathy voice, laryngeal stridor (high-pitched sound heard when a person is breathing) |
saying to remember cranial nerve names in order | Oh, Oh, Oh To Take A Family Vacation! Go Vegas After Hours! |
saying to remember sensory/motor/both in order | Some Say Marry Money, But My Brother Says Big Bucks Makes Money |
spinal nerves are ____ nerves that... | mixed, carry sensory and motor signals from the periphery to the CNS and vice versa |
__ pairs of spinal nerves correspond roughly to each _______________ | 31, segment of the vertebral column |
sections of spinal nerves: | 8 cervical (C1-C8), 12 thoracic (T1-T12), 5 lumbar pairs (L1-L5), 5 sacral pairs (S1-S5), and 1 coccygeal |
dermatome | area of skin mainly supplied by a single spinal nerve |
A relfex requires: | stimulus at peripheral receptor, processing in CNS (spinal cord or brainstem), motor response at peripheral effector). May be either monosynaptic or polysynaptic |
Varicella-Zoster virus | can cause 2 diseases: chickenpox (varicella) and shingles (herpes zoster or zona). After recovering from chickenpox, the virus is dormant in the nerve roots. It can stay that way forever or can wake up due to weak immune system or stress. |
nerve plexus | network combining spinal nerves that serve the same area of the body |
cervical | head, neck, and shoulder |
brachial | chest, shoulder, arms, and hands |
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