Unit VIII Flashcards
Special sense organ of vision Pg 281
Eye
What germ layer is the eye derived from? Pg 281
Ectoderm
What are the retina and pigmented structures derived from? Pg 281
Neuroectoderm of the forebrain
What are the lends and cornea derived from? Pg 281
Surface ectoderm
What are the fibrous coats derived from? Pg 281
Neural crest mesenchyme
What are the 3 coats or tunics of the eye? Pg 281
1) fibrous
2) vascular
3) nervous
What are the components of the fibrous tunic? Pg 281/2
Sclera and cornea
What maintains shape if the pressure inside the eye increases? Pg 281
Sclera
Where do the extraocular muscles attach? Pg 282
Sclera
Where does the sclera transition to the cornea? Pg 282
Limbus
What is the primary refractory part of the eyeball? Pg 282
Cornea
What is the shape of the cornea? Pg 282
Convex to the anterior
What are the 5 layers of the cornea? Pg 282/3
1) corneal epithelium
2) anterior limiting lamina
3) substantia propria
4) posterior limiting lamina
5) endothelium
What are the components of the vascular tunic? Pg 283
Choroid, ciliary body, iris
What is darkly pigmented to limit the passage of light to and from the retina? Pg 283
Choroid
How is the choroid attached to the sclera? Pg 283
Loosely, except where the optic nerve penetrates it
What suspends the lens and produces the aqueous fluid? Pg 283
Ciliary body
What contains the ciliary muscle? Pg 283
Ciliary body
Aqueous fluid is produced where in the eye? Pg 283/7
Posterior chamber of the anterior segment
What is the action of the ciliary muscles? Pg 283
Allows the lens to become more convex, allowing for near vision
What divides the anterior and posterior chambers of the anterior segment of the eye? Pg 283
Iris
What two muscles control the size of the pupil? Pg 283/4
1) sphincter pupillae
2) dilator pupillae
What is the action and arrangement of the sphincter pupillae? Pg 284
Constriction of the pupil, circumferentially arranged
What is the action and arrangement of the dilator pupillae? Pg 284
Dilation of the pupil, radially arranged
What are the components of the nervous tunic? Pg 284
Retina
Why is the retina considered a specialized portion of the brain? Pg 284
Because it is an outgrowth of diencephalon
What are the 10 layers of the retina from external to internal? Pg 284/5
1) pigmented layer
2) outer segment (rods and cones)
3) external limiting membrane
4) outer nuclear layer
5) outer plexiform layer
6) inner nuclear layer
7) inner plexiform layer
8) ganglion cell layer
9) nerve fiber layer
10) internal limiting membrane
Where does detached retina occur? Pg 284
Pigmented layer
5 cells involved with the vision pathway? Pg 286
Photoreceptors -> inner nuclear layer(bipolar) -> ganglionic cell layer(multipolar) -> lateral geniculate body -> brodmann area 17
Point at which the optic nerve attaches to the eyeball Pg 286
Optic disk
True or False: the optic disk has photoreceptors Pg 286
False, NO photoreceptors
What is the area of clearest vision? Pg 286
Fovea centralis/Macula lutea
What is the center of the macula lutea? Pg 286
Fovea centralis
____(rods or cones) are the only photoreceptors in the fovea centralis Pg 286
Cones
What are the refractory components of the eye? Pg 286
Cornea, aqueous humor, lens, vitreous body
What separates the anterior segment from the posterior segment? Pg 287
Lens
Condition of the lens hardening with age Pg 287
Presbyopia
Condition of the lens becoming less and less transparent Pg 287
Cataracts
What fills the posterior segment? Pg 287
Vitreous body
A vestigial structure connecting the optic nerve and posterior aspect of the lens Pg 287
Hyaloid canal
What did he hyaloid canal contain? Pg 287
Fetal hyaloid artery
What extraocular muscle is supplied by the trochlear nerve? Pg 287/8
Superior oblique
What extraocular muscle is supplied by the abducens nerve? Pg 287/8
Lateral rectus
What extraocular muscles are supplied by the oculomotor nerve? Pg 287/8
Superior rectus, inferior rectus, medial rectus, inferior oblique
Pathway of the lacrimal apparatus Pg 288
Lacrimal gland -> excretory ducts -> lacrimal ducts -> lacrimal sac -> nasolacrimal duct -> inferior nasal meatus
What are the tarsal glands? Pg 288
Modified sebaceous gland
What do the tarsal glands do? Pg 288
Produces an oily substance to reduce the evaporation of tears
What is the arterial supply to the eye? Pg 289
One medial/one lateral long posterior ciliary artery, 6-12 short ciliary arteries, 6-8 anterior ciliary arteries, and central retinal artery
What is the only artery to supply the retina? Pg 289
Central retinal artery
What is the venous drainage from the eye? Pg 289
One medial/one lateral long posterior ciliary vein, 6-8 anterior ciliary veins, and central retinal vein
What is the nerve supply to the eyeball? Pg 290
Branches of the nasociliary nerve of the ophthalmic division trigeminal
Ectodermal thickening on lateral “head” Pg 290
Placode
What does the auditory vesicle give rise to? Pg 290
Membranous inner ear
What is the auditory tube and tympanic cavity derived from? Pg 290
First pharyngeal pouch
What is the malleus derived from? Pg 290
Dorsal end of the ventral mandibular cartilage
What is the incus derived from? Pg 290
Dorsal end of the first pharyngeal arch
What is the stapes derived from? Pg 290
Dorsal end of the second pharyngeal arch
What is the tympanic membrane derived from? Pg 290
Interstitial mesoderm
What is the external acoustic canal derived from? Pg 290
First pharyngeal groove
What is the auricle derived from? Pg 290
Groove next to the first pharyngeal groove
What is the purpose of the auricle? Pg 291
Funnel sound waves
3 extrinsic muscles of the auricle Pg 292
1) anterior auricular
2) superior auricular
3) posterior auricular