Ch. 15 - Special Senses Flashcards
Medial rectus
- Moves eye medially
- Oculomotor III
- muscle responsible for crossing ones eyes
Superior rectus
- elevates eye
- Oculomotor III
- muscle responsible for looking up
Inferior rectus
- Depresses eye
* Oculomotor III
Inferior oblique
- Elevates eye and turns it laterally
* Oculomotor III
Superior oblique
- Depresses Eye And turns it laterally
- Trochlea IV
- damage to Trochlear nerve causes inability to contract this muscle
Lateral rectus
- Moves eye laterally
- Abducens VI
- damage to cranial nerve VI causes inability to contract this muscle
- inability for eyeball to look right would indicate dysfunction of this muscle
Optic chiasm
- point where optic nerves are connected to each other just inside the cranial cavity and anterior to the pituitary gland
- area where medial ganglion cell axons cross over and project to opposite side of brain
- Half of the fibers of each optic nerve decussate here before reaching the visual cortex
Fovea centralis
• The portion of the retina with the greatest visual acuity
Vitreous humor
• A jelly like substance in the posterior cavity of the eye
Optic tract
- track that extends from the optic chiasma to the lateral geniculate nucleus of the thalamus
- The route of the ganglionic axons beyond the chiasma
Visual cortex
- Area in the occipital lobe of the cerebral cortex that integrates visual information and produces the sensation of vision
- The cerebral area that integrates messages from retina
Cataract
- increased cloudiness of the lens resulting in decreased vision or loss of vision
- treatment involves removal of the lens
Macula degeneration
- acute loss of vision; both eyes are typically involved
* Central vision is affected, while peripheral vision remains intact
Myopia
- difficulty seeing distant objects
- nearsighted
- eyeball is too long and the focal point is in front of the retina
Astigmatism
- cornea or lens is not uniformly curved, so images not sharply focused
- a type of refractory error
- The cornea or the lens is elliptically rather then spherically curved
Glaucoma
- increased intraocular pressure that can lead to loss of vision
- A state of elevated pressure with in the eye that occurs when the scleral venous sinus is obstructed so the aqueous humor is not reabsorbed as fast as it is secreted
- maybe caused by increased aqueous humor fluid production or failure to drain
- excessive pressure build up in aqueous humor; may destroy retina or optic nerve, resulting in blindness
Auditory ossicles
- tiny bones in the middle ear
* malleus, incus, stapes
Organ of corti
• structure in the cochlea in which hair cells transduce movements from soundwaves into electrochemical signals
Endolymph
• A fluid contained in the membranous labyrinth of the inner ear
Perilymph
• fluid between the membranous and bony labyrinth
Auditory tube
• connects the middle ear to the pharynx
Oval window
- A membrane covered opening that leads from the middle ear to the vestibule of the inner ear
- ossicles connect the structure to eardrum
Conjunctivitis
- inflammation of conjunctiva, usually from bacterial infection
- pink eye is an example of this
Why does a persons nose run when he cries?
• tears drain into the nasal cavity via the nasolacrimal duct
Intrinsic eye muscles
- ciliary muscles
- sphincter pupillae
- dilator pupillae
Color vision
• is a function of cone cells
Vestibulocochlear nerve - CN VIII
• responsible for hearing and balance
Olfactory nerve - CN I
• responsible for sense of smell
Optic nerve - CN II
• responsible for vision
Oculomotor nerve - CN III
• responsible for eye movements by controlling for the extraocular muscles
Trochlear nerve - CN IV
• responsible for eye movement
Trigeminal nerve - CN V
• responsible for cutaneous sensations of the face and controlling the muscles of mastication
Abducens nerve - CN VI
• responsible for eye movement
Facial nerve - CN VII
• responsible for the muscles involved in facial expressions, as well as part of the sense of taste and production of saliva