Special Sense Organs Part 2

Question 1

What coat/tunic of the eye is an outgrowth of the diencephalon and can be considered a specialized portion of the brain?

Answer 1

nervous tunic or retina

Question 2

What is the retina in contact with externally? internally?

Answer 2

choroid externally;

vitreous body internally

Question 3

What are the 10 layers of the retina from external to internal?

Answer 3

Pigmented layer (cementing layer), Photosensitive layer (rods and cones), External limiting membrane, Outer nuclear layer, Outer plexiform layer, Inner nuclear layer, Inner plexiform layer, Ganglion cell layer, Nerve fiber layer, and Internal limiting membrane. 
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Question 4

What are the 5 cells involved in the vision pathway?

Answer 4

Rod/Cone, Bipolar, Ganglionic, Multipolar, and cells in Broadman area 17

Question 5

What do rods and cones synapse with?

Answer 5

Inner nuclear layer

Question 6

What do bipolar cells from the inner nuclear layer synapse with?

Answer 6

ganglionic cell layer cells

Question 7

From the Ganglionic cell layer, where do multipolar cells carry info to?

Answer 7

Lateral geniculate body

Question 8

From where do axons form the optic radiation? where do they synapse?

Answer 8

lateral geniculate body; synapse in BA 17 of occipital lobe

Question 9

What retinal structures are visible upon funduscopic exam?

Answer 9

optic disc and macula lutea

Question 10

T/F: the optic disc is the point where the optic nerve attaches to the eyeball, appears white or yellowish, and contains many photoreceptors.

Answer 10

False; contains no photoreceptors

Question 11

Where do major blood vessels enter the eyeball?

Answer 11

optic disc

Question 12

What is the darker area in the center of the fundus?

Answer 12

macula lutea

Question 13

Where is the fovea centralis?

Answer 13

in the middle of the maculae lutea

Question 14

Where is the area of clearest vision?

Answer 14

macula lutea

Question 15

What photoreceptors are found in the macula lutea?

Answer 15

cones only

Question 16

What are the refractory components of the eyeball?

Answer 16

Cornea, Aqueous humor, Lens, and Vitreous body

Question 17

What refractory component of the eyeball is the most anterior and also the primary refractory structure?

Answer 17

cornea

Question 18

What is the clear fluid secreted by the ciliary processes on the posterior aspect of the ciliary body?

Answer 18

Aqueous humor

Question 19

T/F: aqueous humor is secreted into the anterior chamber.

Answer 19

False; secreted into the posterior chamber of the anterior segment (posterior to the iris)

Question 20

After passing through the pupil into the anterior chamber and then travelling laterally, where does the aqueous humor ultimately leave the eyeball?

Answer 20

through the scleral venous sinus

Question 21

What results from increased pressure within the anterior segment of the eyeball?

Answer 21

glaucoma which can lead to blindness

Question 22

Which refractory component of the eyeball is transparent, biconvex, and avascular?

Answer 22

lens

Question 23

What does increasing the convexity of the lens allow for?

Answer 23

near vision

Question 24

What separates the anterior segment of the eye from the posterior segment?

Answer 24

lens

Question 25

What is presbyopia?

Answer 25

lens gets harder with age resulting in more difficult near vision

Question 26

What forms when the lens becomes less and less transparent?

Answer 26

cataracts

Question 27

What refractory component of the eye fills the posterior segment, is gelatinous and transparent, and contains a vestigial structure connecting the optic nerve and posterior aspect of the lens? what is this vestigial structure called?

Answer 27

vitreous body;

hyaloid canal

Question 28

What did the hyaloid canal contain during development and what is its functional purpose in the adult?

Answer 28

fetal hyaloid artery;

serves no purpose in the adult

Question 29

What are the 3 accessory structures of the eye?

Answer 29

extraocular muscles, lacrimal apparatus, and tarsal glands

Question 30

What are the 6 extraocular muscles considered to be accessory structures of the eye?

Answer 30

superior rectus, inferior rectus, lateral rectus, medial rectus, superior oblique, and inferior oblique muscles

Question 31

What glands are located superolaterally to the eyeball and secrete tears to the surface of the eye via excretory ducts? How are tears drained from the eyeball?

Answer 31

lacrimal glands;

lacrimal ducts below and medial to the eyeball drain tears into the lacrimal sac

Question 32

What is the most superior part of the nasolacrimal duct and where is it found specifically?

Answer 32

lacrimal sac found in a groove between the lacrimal bone and the maxilla

Question 33

Where does the nasolacrimal duct drain tears from and into? He told a story about his daughter here.

Answer 33

drains from lacrimal sac into inferior nasal meatus (which can sometimes clog, especially in kids)