Unit 2_Special Senses: Vision Flashcards
What system do the following control:
Focus images on back of retina (fovea; where rods and cones are located)
Adjust dark/light intensity
Color detection
Shape and movement detection
Localize visual stimuli
Functions of the Visual System
What structure in the eye includes the socket, contains eyeball, blood vessels, nerves, and fractures can cause visual disturbance?
Orbit
What muscles under control of vestibular system and brainstem keep eye fixated on target?
Extraocular muscles
What structure protects eyes, includes Orbicularis oculi (closes eyelid - CN VII), Levator palpebrae superioris (opens eyelid - CN III), smooth muscle Sympathetic Nervous System (SNS) also opens eye?
Eyelid
What disease is caused by an injury to Orbicularis oculi (closes eyelid-CN VII) or a lesion of the nerve or facial motor nucleus in pons?
Bell’s Palsy
What disease is caused by an injury to Levator palpebrae superioris (opens eyelid-CN III) or a
lesion CN III or oculomotor nucleus in midbrain?
Ptosis
What structure is needed for tears, innervated by CN VII and a lesion CN VII or lacrimal nucleus in pons (Bell’s Palsy) inability to tear (dry eye)?
Lacrimal Glands
What structure of the eyeball is the bump on eye that helps with light refraction and focusing image, acts as a protective mechanism (blink reflex in response to touch), includes sensory innervation by CN V and reflex-CNV and CNVII?
Lesion either CNV or CNVII or facial motor nucleus in pons will impair blink reflex to touch.
Cornea
What structure of the eyeball includes the pupil (hole), constricts and dilates in response to light,
controlled by Para- & Sympathetic nerves, Para-constricts CNIII from Edinger Westphal nucleus in the midbrain, sympathetic nervous system stimulation causes dilation?
Iris
What structure of the eyeball is an extension of anterior wall of orbit, includes smooth muscles attach to lens (contracts and changes shape of lens), includes ciliary muscles – innervated by E-W nucleus in midbrain CNIII, helps with focusing on close objects?
Ciliary Body
What structure of the eyeball sits in retina and includes 2 kinds: Rods and Cones?
Photoreceptor
What kind of photoreceptor is the following:
-highly sensitive to light for night vision
-no color vision
-does not help with visual acuity
Rods
What kind of photoreceptor is the following:
-for colors and visual acuity
-low sensitivity to light
Cones
What is the point of entry of the optic nerve on the retina, insensitive to light?
The blind spot
What visual field includes the following:
Nasal retina from left eye
Temporal retina from right eye
Left Visual Field
What visual field includes the following:
Nasal retina from right eye
Temporal retina from left eye
Right Visual Field