11418505
Description
Flashcards by Megan Cobarruvias, updated more than 1 year ago
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Created by Megan Cobarruvias
over 6 years ago
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| Question | Answer |
| If an animal lacks a menace response,what does it imply? | Optic nerve is damaged = no SSA signal; Facial nerve damaged = failed motor to orbicularis oculi m. via palpebral branch of the auriculotemporal n. (VII) |
| What would be the consequences of a tumor in the occulomotor nerve nucleus? | Ptosis: upper eyelid cannot be raised due to paralysis of levator palpebrae superioris m. Lateral strabismus: undamaged lateral rectus m. and retractor bulbi m. contraction deviates eyeball to the lateral side (eye m. innervated by CN III non-functional |
| What does the lack of blink response at the medial canthus suggest? | Suggests injury to the ophthalmic n. (V); specifically the frontal n. and infratrochlear n. of the nasociliary branch |
| Describe the cause of Horner's Syndrome and name its clinical signs. | Injury to sympathetic division of the autonomic nerves that innervate the eye Signs: ptosis, constricted pupil of the eye (miosis), sunken eye (enophthalmos), conjunctival hyperemia and prolapse of the nictitating membrane |
| What part of the cat is abnormal? Which cranial nerves are close to this structure? | Tympanic bulla May require a tympanic bulla osteotomy The glossopharyngeal, vagus, accessory, and hypoglossal nerve all exit the skull through the tympano-occipital fissure (hypoglossal canal opens into fissure) |
| What is the cause of medial strabismus? | Damage to the abducens n. (CN VI) causes inability to retract eyeball due to non-functional lacteral rectus and retractor bulbi |
| What response is elicited by the upper lip pinch test? Which muscle is being pinched and what cranial nerve innervates it? | Initiates snarling response; pinching orbicularis oris m. to activate muscles of facial expression innervated by the facial nerve |
| If the nostrils (interior) are tickled with a feather tip or cotton bud elicits no reaction, which cranial nerve branch is most likely affected? | Caudal nasal branch of the maxillary n. (V) Caudal nasal nerve runs through sphenopalatine foramen to innervate nasal mucosa and ventral nasal meatus |
| What makes up the pharyngeal plexus? | The pharyngeal branches from the distal and proximal vagal ganglia (CN X), pharyngeal branch of the glossopharyngeal n. (CN IX), branches from the hypoglossal n., and postganglionic sympathetic axons from the cranial cervical ganglion |
| Which types of fibers from the pharyngeal plexus mediate the gag reflex? How is it mediated? | GSA (pharyngeal mucosa) and GSE (pharyngeal m.) When a bitter substance is in the caudal 1/3rd of the tongue/laryngopharynx, the hyopharyngeus, thyropharyngeus, and cricopharyngeus contract simultaneously to prevent entry into the esophagus. The hyoglossus, genioglossus and geniohyoideus m. pull the tongue rostrally to spit out |
| Describe the sensory input for cough reflex | SVA and pharyngeal GVA of the cranial laryngeal n. (CN X) signal to close the aditus laryngis when food or water reaches the oropharynx; accidental entry irritates laryngeal mucosa via GVA |
| Describe the motor response of the cough reflex | Cranial laryngeal n. contracts cricothyroideus and caudal laryngal n. contracts the cricoarytenoideus dorsalis and all other muscles of the larynx to produce the cough |
| If a dog is vestibular, which cranial nerve may be involved? How is this cranial n. being affected? | Vestibulocochlear n. Inflammation from an inner ear infection may be affecting the nerve's ability to transmit impulses relating to the position of the head relative to gravity and to linear and angular acceleration. |
| Why can the vestibular n. and the cochelar n. be affected independently? What parts of the ear do they innervate? | Vestibular and cochlear nerve have two separate ganglia and two separate nuclei of origin. The vestibular n. innervates the hair cells in cristae ampullare and macula utericuli and sacculi of membranous labyrinth. The cochlear n. innervate hair cells of the spiral organ in the cochlear duct |
| What possible effects could result from damage to the mandibular n. (V)? | Atrophy of masticatory muscles, temporal fossa, zygomatic arch. If bilateral, will caused dropped lower jaw. |
| If a patient presents with dorsolateraral strabismus and abnormal position ov vessels in the fundus, what cranial n. could be affected? | Trochlear n. (CN IV); dorsal oblique m. non-functional |
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