Ear

Question 1

sound conductor from the external to the internal ear

Answer 1

Middle ear

Question 2

converts sound waves into nerve impulses and registers changes in equilibrium

Answer 2

Internal ear

Question 3

The first indication of the developing ear can be found in approx how many days?

Answer 3

22 days

Question 4

thickening of the surface ectoderm on each side of the rhombencephalon

Answer 4

Otic placodes

Question 5

The otic placodes invaginate rapidly to form the

Answer 5

Otic or auditory vesicles (otocysts)

Question 6

Ventral component of a vesicle

Answer 6

Saccule

Cochlear duct

Question 7

Dorsal component of an otic vesicle

Answer 7

Utricle
Semicircular canals
Endolymphatic duct

Question 8

The epithelial structures from the components of the vesicles form the

Answer 8

Membranous labyrinth

Question 9

the saccule forms a tubular outpocketing at its lower pole (cochlear duct)

Answer 9

6th wk

Question 10

penetrates the surrounding mesenchyme in a spiral fashion until the end of the eighth week, when it has completed 2.5 turns

Answer 10

Cochlear duct

Question 11

The cochlear duct penetrates the surrounding mesenchyme in a spiral fashion until the end of what week

Answer 11

8th wk

Question 12

The connection of the cochlear duct with the remaining portion of the saccule is then confined to a narrow pathway, the ?

Answer 12

Ductus reunens

Question 13

Mesenchyme surrounding the cochlear duct soon differentiates into cartilage. This cartilaginous shell undergoes vacuolization, and two perilymphatic spaces, the scala vestibuli and scala tympani, are formed

Answer 13

10th wk

Question 14

In the 10th week, the cartilaginous shell undergoes vacuolization, and two perilymphatic spaces?

Answer 14

Scala vestibuli

Scala tympani

Question 15

The cochlear duct is then separated from the scala vestibuli by the ——– and from the scala tympani by the ————-

Answer 15

Vestibular membrane

Basilar membrane

Question 16

The lateral wall of the cochlear duct remains attached to the surrounding cartilage by the ————

Answer 16

Spiral ligament

Question 17

The median angle of the cochlear duct is connected to and partly supported by a long cartilaginous process, the ———-

Answer 17

modiolus

Question 18

the future axis of the bony cochlea

Answer 18

modiolus

Question 19

The epithelial cells of the cochlear duct further develop and form two ducts

Answer 19

Inner ridge - future spiral limbus

Outer ridge

Question 20

Sensory cells of the auditory system

Answer 20

Hair cells

Question 21

The outer ridge forms how many rows of hair cells

Answer 21

1 inner

3 or 4 outer

Question 22

Covers the hair cells

Answer 22

Tectorial membrane

Question 23

Fibrillar gelatinous substance attached to the spiral limbus, that rests with its tip on the hair cells

Answer 23

Tectorial membrane

Question 24

Rests with its tip on the hair cells

Answer 24

Spiral limbus

Question 25

Sensory cells + tectorial membrane

Answer 25

Organ of Corti

Question 26

Impulses received by the organ of corti are transmitted to the spiral ganglion and then to the nervous system by the -------

Answer 26

Auditory fibers of cranial nerve III

Question 27

Semicircular canals appear as flattened outpocketings of the utricular part of the otic vesicle

Answer 27

6th wk

Question 28

One end of each of the semicircular canal dilates to form the ----------, and the other, the ------------, does not widen

Answer 28

Crus ampullare | Crus nonampulare

Question 29

How many crura enter the utricle?

Answer 29

5 3 w/ an ampulla, 2 without *only two of the crus nonampullare fuse

Question 30

Cell in the ampullae form a crest, -----------, containing sensory cells for maintenance of equilibrium

Answer 30

Crista ampullaris

Question 31

Sensory area for equilibrium in the walls of the utricle and saccule

Answer 31

Maculae acusticae

Question 32

Impulses generated by the cristae and maculae carried to the brain by

Answer 32

Vestibular fibers of cranial nerve VIII

Question 33

During formation of the otic vesicle, a small group of cells breaks away from its wall and forms the

Answer 33

Statoacaoustic ganglion

Question 34

Other cells of the statoacoustic ganglion ar derived from the

Answer 34

Neural crest

Question 35

The statoacoustic ganglion splits into what portions?

Answer 35

Cochlear | Vestibular

Question 36

Supplies the sensory cells of the organ of Corti

Answer 36

Cochlear portion

Question 37

Supplies the sensory cells of the saccule, utricle, and semicircular canals

Answer 37

Vestibular portion

Question 38

Originates in th endoderm; derived from the first pharyngeal pouch

Answer 38

Tympanic cavity

Question 39

Expands in a lateral direction & comes in contact wt th floor of the 1st pharyngeal cleft

Answer 39

1st pharyngeal pouch

Question 40

Distal part of the pouch; widens and gives rise to the primitive tympanic cavity

Answer 40

Tubotympanic recess

Question 41

Proximal part of the pouch; remains narrow; forms the

Answer 41

Auditory tube (eustachian tube)

Question 42

Structure thru whc the tympanic cavity communicates wt the nasopharynx

Answer 42

Auditory tube (eustachian tube)

Question 43

Malleus and incus are derived from

Answer 43

The cartilage of the 1st pharyngeal arch

Question 44

The stapes is derived from

Answer 44

The 2nd pharyngeal arch

Question 45

The muscle of the malleus is innervated by

Answer 45

Tensor tympani | Mandibular branch of the trigeminal nerve

Question 46

The Muscle attached to the stapes is innervated by

Answer 46

Stapedius muscle | Facial nerve

Question 47

Late fetal life, tymapnic cavity expands dorsally by vacuolization of surrounding tissues to form

Answer 47

Tympanic antrum

Question 48

After birth, epithelium lined air sacs are formed when the tympanic cavity invades the mastoid process

Answer 48

Pneumatization Mastoid air sacs

Question 49

External auditory meatus develops from

Answer 49

The dorsal portion of th 1st pharyngeal cleft

Question 50

Epithelial cells at the bottom of the meatus proliferate, forming a solid epithelial plate, the meatal plug

Answer 50

Beginning of the 3rd mon

Question 51

The meatal plug dissolves | The epithelial lining of the floor of the meatus participates in formation of the definitive eardrum

Answer 51

7th mon

Question 52

The eardrum is made up of

Answer 52

1. Ectodermal epithelial lining - bottom of auditory meatus 2. Endodermal epithelial lining - tympanic cavity, 3. Interm layer of connective tissue/mesenchyme

Question 53

The major part of the eardrum is attached to the handle of the malleus, the rest forms the

Answer 53

Separation bet the external auditory meatus and the tympanic cavity

Question 54

The auricle develops from

Answer 54

6 mesenchymal prolifs at the dorsal ends of the 1st and 2nd pharyngeal arches, surrounding the 1st pharyngeal cleft

Question 55

-----------, three on each side of the external meatus, later fuse and form----------

Answer 55

Auricular hillock | Definitive auricle

Question 56

Intially, the external ears are located where?

Answer 56

In the lower neck region Wt development of the mandible , they ascend to the side of the head at the level of the eyes

Question 57

Cased by abnormal development of the membranous and bony labyrinths or by malformations of the auditory ossicles and eardrum

Answer 57

Congenital hearing loss

Question 58

Skin tags

Answer 58

Periauricular appendages

Question 59

Shallow depressions

Answer 59

Pit

Question 60

Pits indicate

Answer 60

Abnormal devt of the auricular hillocks

Question 61

Periauriclar appendages may be caused by

Answer 61

Accessory hillocks

Question 62

Transfer sound from the tympanic membrane to the oval window

Answer 62

Ossicles

Question 63

Eardrum

Answer 63

Tympanic membrane

Question 64

Sound collecting organ

Answer 64

External ear