Eye and Ear B

Question 1

What does control of shape of lens do>

Answer 1

Vissual accomodation

Question 2

From what does the upper eylid develop from?

Lower Eyelid?

Answer 2

Upper: Frontonasal Process

Lower: Maxillary process

Question 3

What occurs to eyelids during gestation, and late gestatin or postnatally?

Answer 3

Gestation: grow together and fuse

Late Gestaion or postnatally: reopen

Question 4

3 distinct subdivisions of ear

Answer 4

External ear

Middle Ear

Inner Ear

Question 5

What part of the ear derives from firsth pharyngeal cleft and surrounding mesenchyme?

Answer 5

External Ear- Auricle

External Auditory Meatus

Outer lining of Tympanic Membrane

Question 6

What produces the exteranl Auditory meatus or Ear canal?

Answer 6

Inward expansion of First Pharyngeal Cleft

Question 7

What produces the meatal plug?

Answer 7

Eptihelial cells at blind end of cleft can grow and produce this plug

Question 8

What does the outer portion of tympanic membrane form from?

Answer 8

Outer ectodermal lining at bottom of Ext. Aud. Meatus

Question 9

What comprises eardrum?

Answer 9

Inner Endodermal Lining from pouch

Mesenchyme between outer membrane and inner one

Question 10

What do auricles develop from?

Answer 10

Mesenchymal tissue in the First and Second pharyngeal arches that surround the first pharyngeal cleft

Question 11

Explain auricle development

Answer 11

Observed as nodules or “auricular hillocks” that enlarge, change shape and fuse in a very species specific manner

Move from base of neck to more definitive location

Question 12

What is the middle ear made up of?

Answer 12

Tympanic Cavity

Auditory Tube

Middle Ear Ossicles

Middle Ear muscels

Question 13

What is the partition between the external and middle ear?

Answer 13

Tympanic membrane (eardrum)

Question 14

What does the dorsal blind end of First Pharyngeal Pouch give rise to?

Answer 14

Auditory of Eustachian Tube and primitive Tympanic cavity

Question 15

What are ossicles derived from?

Answer 15

Mesenchyme of First and Second Pharyngeal Arches

Question 16

Ossicles and their derivation

Answer 16

Malleus (Hammer) : 1 Pharyngeal Arch

Incus (Anvil): 1 Pharyngeal Arch

Stapes (Stirrup): 2nd pharyngeal arch

Question 17

Muscles related to Ossicles

Answer 17

Tensor tympani - from 1st arch innvervated by Cranial Nerve V

Stapedius - From 2nd arch and innervated by Cranial Nerve VII

Question 18

What does the inner ear consist of?

Answer 18

Membranous labyrinth

Vestibular and Acoustic Ganglia associated with Vestibulocochlear nerve VIII

Question 19

What does the membranous labyrinth consist of?

Answer 19

Vestibulocochlear Organ

Question 20

What is the Vestibulocochlear Organ involved in?

Answer 20

Hearing

Balance

Question 21

What does the inner ear arise from?

Answer 21

Paired thickenings of ectoderm (octic placodes)

Question 22

What occurs to oticc placodes?

Answer 22

Invaginated placodes pinch off into otic vesicles that separate from ectoderm

Vessicles fill with endolymph fluid

Cells bud off the otic vesicle epithelium forming ganglia

Question 23

What does the first elongation of inner ear form?

Answer 23

Endolymphatic duct

Question 24

What two regions form in otic vesicle?

Answer 24

Utricle (dorsally)

Saccule (Ventrally)

Question 25

What develops from Utricle portion of otic vessicle?

Answer 25

Semicircular ducts

Question 26

What form at the ends of each semicircular duct?

Answer 26

Ampullae

Question 27

What are ampullae

Answer 27

Sensory organs of balance

Question 28

What forms from the ventral part of the otic vessicle?

Answer 28

Conchlear duct

Question 29

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Question 30

Slide 28