THE CRANIAL NERVES HONORS ANATOMY PHYSIOLOGY CRANIAL NERVES
- Slides: 46
THE CRANIAL NERVES HONORS ANATOMY & PHYSIOLOGY
CRANIAL NERVES � 12 -pair �named “cranial” because each passes thru a foramina of the cranium �part of PNS �each with roman numeral (order from anterior posterior in which nerves arise from base of brain) & a name that indicates nerve distribution
CRANIAL NERVES �classified as: sensory 2. motor 3. mixed (sensory & motor) 1.
Cranial Nerve I: Olfactory �olfact = to smell �sensory �olfactory epithelium on superior surface of nasal cavity just inferior to cribiform plate of ethmoid bone �olfactory receptors are bipolar neurons each: single odor-sensitive dendrite their unmyelinated axons join above plate form rt or lt olfactory nerves
Course of Olfactory Nerve �olfactory nerves end in pair of olfactory bulbs: masses of gray matter resting just above cribiform plate where they synapse with next neurons in olfactory pathway
Course of Olfactory Nerve �axons of these neurons make up the olfactory tracts posteriorly to primary olfaction center in temporal lobe
Cranial Nerve II: Optic Nerve �optic = eye �sensory �rods & cones in retina: receptors initiating visual signals & relay them bipolar cells optic ganglion neurons their axons join forming optic nerves �pass thru optic foramen optic chiasm: a cross-over of medial half of each eye to opposite side (lateral half does not cross
Optic Chiasm
Optic Tracts �from optic chiasm optic tracts most axons thalamus synapse with neurons whose axons primary visual area of occipital lobe some axons synapse with motor neurons in midbrain extrinsic eye muscles
Cranial Nerve III: Oculomotor �oculo = eye �mixed, mainly motor �its motor nucleus in ventral part of midbrain � 2 branches pass thru superior orbital fissure
Oculomotor Nerve Extrinsic Muscles of Eye Inferior Branch Superior Branch �axons innervate: superior rectus 2. levator palpebrae superioris (upper eyelid) 1. medial rectus 2. inferior rectus 3. inferior oblique
Oculomotor Nerve �inferior branch also: 1. 2. parasympathetic innervation to intrisic muscle of eye (smooth muscle) ciliary muscle: adjusts lens for near/far vision circular muscle of iris: contracts/relaxes in response to amt of light (pupils constrict/dilate)
Oculomotor Nerve: Sensory �proprioception: nonvisual perception of movements & positions of body
Cranial Nerve IV: Troclear Nerve �trochle = pulley �mixed, mainly motor �smallest of the 12 cranial nerves �only 1 that arises from posterior of midbrain
Cranial Nerve IV: Troclear Nerve �motor: �axons from nucleus in midbrain superior orbital fissure �innervates superior oblique muscle �sensory: proprioception in superior oblique
Cranial Nerve IV: Troclear Nerve
Trigeminal Nerve V �largest of 12 cranial nerves �mixed: sensory: ganglion in temporal bone motor: neurons in pons
Cranial Nerve V: Trigeminal Nerve �tri: has 3 branches Ophthalmic: sensory only: upper eyelids, eyes, lacrimal glands, upper nasal cavity, side of nose, forehead, anterior ½ of scalp 2. Maxillary: sensory only: mucosa of nose, palate, part of pharynx, upper teeth, upper lip, lower eyelids 3. Mandibular: sensory: anterior 2/3 of tongue (not taste), cheek, lower teeth motor: muscles of mastication 1.
Trigeminal Nerve
Cranial Nerve VI: Abducens Nerve �ab: away / ducens: to lead (nerve impulses causes abduction of eyeball) �mixed mainly motor �nucleus in pons (motor): innervates lateral rectus muscle �sensory: proprioception in lateral rectus
Abducens Nerve
On Which Side is VI not Functioning?
Cranial Nerve VII: Facial Nerve �mixed �sensory: taste buds anterior 2/3 of tongue, proprioceptors in face & scalp �motor: nucleus in pons innervates muscles of facial expression + stylohyoid muscle & posterior belly of digastric muscle �parasympathetic: lacrimal glands, palatine glands, salivary glands: sublingual & sub-mandibular
Facial Nerve
Cranial Nerve VIII: Vestibulocochlear Nerve �vestibule: small cavity; cochlear: snail-like �mixed, mainly sensory � 2 branches Vestibular: 1. equilibrium 2. Cochlear: hearing motor: hair cells of spiral organ
Cranial Nerve IX: Glossopharyngeal Nerve �glosso: tongue, pharyngeal: throat �Mixed �sensory: taste buds & somatic sensory receptors on posterior 1/3 tongue, proprioceptors in swallowing muscles, baroreceptors (stretch) in carotid sinus, chemoreceptors in carotid bodies �motor: from nuclei in medulla, exit thru jugular foramen, innervate stylopharyngeus muscle (elevates pharynx & larynx) �parasympathetic: motor: stimulate parotid gland to secrete saliva
Cranial Nerve X: Vagus Nerve �vagus: wanderer, vagrant �mixed �distributed from head abdomen
Vagus Nerve �sensory: skin of external ear taste buds in epiglottis & pharynx proprioceptors in muscles of neck & throat baroreceptors in arch of aorta & chemoreceptors in aortic bodies visceral sensory receptors in most organs of thorax & abdominal cavities
Vagus Nerve �parasympathetic motor: heart & lungs glands in GI tract smooth muscle of airways, esophagus, stomach, gall bladder, small intestine, most of large intestine
Distribution of Vagus Nerve
Cranial Nerve XI: Accessory Nerve �mixed �originates from both the brainstem & spinal cord �cranial root: motor: from medulla thru jugular foramen supplies voluntary muscles of pharynx, larynx, & soft palate �spinal root: mixed, mainly motor:
Cranial Nerve XI: Accessory Nerve �spinal root: mixed, mainly motor: neurons in anterior gray horn of C 1 – C 5 axons come together foramen magnum jugular foramen innervates sternocleidomastoid & trapezius muscles sensory: proprioceptors in muscles it supplies
Cranial Nerve XII: Hypoglossal �hypo: below, glossal: tongue �mixed �sensory: proprioceptors in tongue muscles medulla �motor: nucleus in medulla hypoglossal canal muscles of the tongue (speech, swallowing)
Development of the Nervous System �begins developing in 3 rd wk from a thickening of ectoderm called the neural plate
Development of the Brain & Spinal Cord
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- Cranial nerves
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- Cranial nerves labeled with roman numerals
- Sensory cranial nerves
- Which cranial nerves are ipsilateral
- Afferent cranial nerves
- Nucleus solitarius cranial nerves
- Crematic reflex
- Ventricles brain
- Olfactory nerve
- Cranial nerves mnemonic
- Horizontal
- Optic chiasm
- Cranial nerve number face
- Figure 14-2 cranial nerves labeled
- Brain nerves labeled
- Proprioception cranial nerves
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- Oculomotor paralysis
- Some say money matters cranial nerves
- Brachioradialis reflex
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- Cranial nerves labeled with roman numerals
- Minor salivary glands
- Cranial nerves
- Peripheral nerves and nerve plexuses
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- Cranial fossa nerves
- Cn 3 test
- Cranial nerves sensory and motor
- Sensory cranial nerves
- Hypoglossal cranial nerve test
- First and second cranial nerves
- Wrist anatomy nerves
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