06/02/2023 Notes Flashcards
What are cranial nerves?
Nerves that are part of the peripheral nervous system that originate on the inferior surface of the brain
How many cranial nerves are there?
12 pairs
What is CN I? Describe what information it sends and its function.
Olfactory Nerve relays sensory information and is responsible for sense of smell
Where are dendrites of olfactory neurons found?
Within the mucosa that covers the superior nasal conchae and adjacent nasal septum
What is cranial nerve II?
The optic nerve is a sensory nerve that relays information from photoreceptors in the retina to the visual cortex within the occipital lobes
What is the optic chiasm?
Converging of optic nerves within the optic foramen that cross nerves on the medial half to the opposite brain
What is bitemporal hemaniopia?
Blindness in the temporal field of vision in both eyes due to the growth of a pituitary tumor that puts pressure on the optic chiasma
What is fundoscopic examination used for when looking within the fundus of the eye?
Papilledema caused by increased intracranial pressure
What is cranial nerve III?
Oculomotor nerve is a motor nerve that controls the intrinsic and extrinsic movement of the eye
What does CNIII innervate?
Many extrinsic muscles of the eye and the intrinsic muscles of the eye that constrict the pupil and muscles that change the shape of the eye to allow focusing
Pressure or damage to the oculomotor nerve can cause what?
Palsy on the ipsilateral side of the head
What specific trauma/pressure can cause palsy on CNIII?
Rostrocaudal brain deterioration, tumors, or cerebral edema
What is CN IV?
Trochlear nerve is a small motor nerve that innervates that muscle of the eye that controls downward and lateral movement of the eye
What is CN V?
Trigeminal nerve is a large mixed nerve that has both sensory and motor functions
What are the sensory functions of the trigeminal nerve?
Involved with sensations of touch, temperature, and pain
What are the three branches of CN V?
Ophthalmic Nerve, Maxillary Nerve, and Mandibular Nerve
What is the photic sneeze reflex?
An inherited condition that causes an individual to sneeze repetitively when exposed to bright lights
Where can dental anesthesia be applied to dead nerves in the lower and upper jaw?
Mandibular foramen in the lower jaw and foramen rotundum in the upper jaw
What are the motor functions of the trigeminal nerve?
Innervates muscles involved with chewing (masseter, temporalis, and medial/lateraly pterygoids)
What is cranial nerve 6?
The abducens nerve is a small motor nerve that controls the extrinsic movement of the eye laterally
What is CN VII?
The facial nerve is a mixed nerve that controls significant quality of life
What are the motor functions of the facial nerve?
Innervates muscles of facial expression (epicranius, buccinators, orbicularis oris, platysma) and stimulates several salivary glands (sublingual and submandibular glands)
What are the sensory functions of CN VII?
Receives impulses of taste from the ANTERIOR portion of the tongue
What is CN VIII?
The vestibulocochlear nerve is a sensory nerve that is composed of both the vestibular and cochlear nerves
What does the vestibular branch of CN VIII do?
Responsible for equilibrium and balance, and sends information to several regions of the brain
What does the cochlear branch of the vestibulocochlear nerve do?
Responsible for hearing and sends information to the cerebral cortex
What is CN IX?
The glossopharyngeal nerve is a mixed nerve that innervates the posterior part of the tongue and a muscle in the throat
What is the motor function of CN IX?
Stimulates the swallowing reflex and secretion of saliva by the parotid gland
What are the sensory functions of the glossopharyngeal nerve?
Originate from chemoreceptors on the back portion of the tongue and sensors in the carotid sinus then enters the cranium to reach the pons and taste areas of insula
What is CN X?
Valgus Nerve is a mixed nerve that originates in the medulla oblongata and innervates several visceral organs of the thoracic and abdominal cavities
What is the longest cranial nerve?
CN X (valgus nerve)
What are the motor functions of CN X?
Innervates most pharynx muscles and the voice box (larynx)
Damage to the valgus nerve can result in what?
Difficulty swallowing, hoarseness, monotone, or mutism
What are sensory functions of CN X?
Receives input from external auditory canal and eardrum, pharynx, larynx, heart, lungs, esophagus, and abdominal organs except for the lower portions of large intestines
What is CN XI?
Accessory nerve is a motor nerve that arises from the medulla and spinal cord
What are the two components of the accessory nerve and their functions?
Cranial root component innervates pharynx muscles that contract while swallowing, and the spinal root innervates trapezius and sternocleidomastoids
What is CN XII?
Hypoglossal nerve is a motor nerve that innervates the muscles of the tongue and some nearby muscles that aid in tongue movement
Damage to the hypoglossal nerve results in what?
Impaired swallowing and difficulty with speech
What are the names of the 12 cranial nerves?
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
Facial
Vestibulocochlear
Glossopharyngeal
Valgus
Accessory
Hypoglossal
What two cranial nerves are involved with taste?
Facial Nerve (CN XII) and Glossopharyngeal Nerve (CN IX)
What is the smallest cranial nerve?
Trochlear Nerve (CN IV)
