Topic # 8 Flashcards

1
Q
  • is a complex organ, with parts derived from ectoderm and mesoderm in the head
    region
A

eye

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2
Q

Parts of the Adult Eye

A
  1. Eyeball
  2. Muscles of the eye
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3
Q
  • wall, anterior compartment, posterior compartment and lens.
A

Eyeball

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4
Q
  • intrinsic and extrinsic muscles
A

Muscles of the eye

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5
Q

The wall of the eye consists of three layers or tunics

A

a. Fibrous tunic
b. Vascular tunic
c. Nervous tunic

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6
Q
  • cornea and sclera
A

Fibrous tunic

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7
Q
  • choroid, ciliary body and ciliary processes and iris
A

Vascular tunic

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8
Q
  • retina
A

Nervous tunic

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9
Q

is composed of anterior and posterior chambers that contain
aqueous humor.

A

The anterior compartment

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10
Q

The posterior compartment consists of the vitreous chamber that contains

A

vitreous
humor

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11
Q

eyes develop from the

A

optic field

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12
Q

Through tissue interaction between the optic field
and the head mesoderm, the single optic field separates into bilateral (2)

A

lateral eye-forming
regions

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13
Q

After formation of the five (5) brain vesicles the two (2) lateral eye-forming regions
associated w/ the diencephalon evaginate laterally to become bilateral

A

optic vesicles

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14
Q

, which connects w/ the diencephalon through the optic stalk, invaginates to form a doublewalled optic cup and the original lumen of the optic vesicle becomes slit-like

A

The optic vesicle

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15
Q

The outer wall of the optic cup thins out to become the

A

pigment layer of the retina.

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16
Q

The inner wall of the optic cup collapses and thickens to become

A

the sensory
(rods and cones) layer of the retina.

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17
Q

During invagination of optic cup a gap along the optic stalk,the ________
is created

A

choroid or optic fissure,

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18
Q

The vitreous or posterior compartment develops from the

A

concavity of the optic cup

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19
Q

The vitreous or posterior compartment develops from the

A

concavity of the optic cup

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20
Q

is formed from ectomesenchyme that
enters the compartment through the optic fissure

A

the vitreous body

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21
Q

The
surface ectoderm overlying the optic vesicles, by induction from the optic vesicles and placode
formation, thickens to form the

A

lens placode.

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22
Q

cells in the deep or inner pole of the lens elongate to form_______ that push
toward the cavity of the lens vesicle, almost obliterating it.

A

lens fibers

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23
Q

Cells in the outer or superficial pole of
the lens form a single layer of cuboidal or columnar epithelium called

A

lens epithelium

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24
Q

Cornea develops from 2 sources:

A

corneal epithelium
Surface ectoderm

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25
Q

Surface ectoderm that overlies the invaginated lens
vesicle, by induction from the

A

lens vesicle and optic cup

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26
Q

forms a 2-cell thick (basal and superficial)

A

corneal epithelium;

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27
Q

secrete a collagenous matrix called primary stroma

A

the basal cells

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28
Q

later on the corneal endothelial cells secrete into______ the primary
stroma causing it to swell

A

hyaluronic acid

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29
Q

Fibroblasts from mesoderm migrate to the primary stroma and produce_____
(that destros the hyaluronic acid); and coarse collagen

A

hyaluronidase

30
Q

Secondary stroma becomes the

A

substantia propria of the cornea.

31
Q

is formed by choroid ectomesenchyme and the superficial edge of the optic cup;

A

The Iris

32
Q

is the reduced opening of the optic cup

A

Pupil

33
Q

is derived from the thickened choroid
ectomesenchyme and caudal part of the overlapping portion of the optic cup

A

Ciliary apparatus (ciliary
body, ciliary processes and ciliary muscles)

34
Q

The sclera provides attachment to the
muscles of the eyeball. In chick, 14 bony rings called______ surround the outer margin
of the cornea

A

sclera ossicles

35
Q

Development of the Accessory Structures of the Eye

A
  1. Eyelids
  2. Conjunctival Sac
  3. Lacrimal Gland
36
Q

Formed by upper and lower folds of ectoderm (skin), each fold includes a mesenchyme
core

A

Eyelids

37
Q

➢ Derived from the space between the eyelid and the cornea

A

Conjunctival Sac

38
Q

➢ Develops by invagination and budding of conjunctival ectoderm.

A

Lacrimal Gland

39
Q

Malformations of the Eye

A
  1. Cyclopia
  2. Anophthalmia
  3. Coloboma
  4. Microphthalmia
  5. Medial strabismus
  6. Cataract
40
Q
  • development of a single eye in the center of the head due to failure of the optic
    field to separate into 2 lateral eye-forming regions
A

Cyclopia

41
Q
  • absence of eye due to failure of optic vesicles to form or to severe inference
    w/ normal growth of optic cup
A

Anophthalmia

42
Q
  • a defect due to failure of the optic fissure to close
A

Coloboma

43
Q
  • small undeveloped eye; results from failure of the vitreous body to exert
    sufficient pressure for growth, often because a coloboma allowed vitreous humor to escape.
A

Microphthalmia

44
Q
  • medial deviation of the eyeball. Common in Siamese cat.
A

Medial strabismus

45
Q
  • loss of clarity of the lens. Mainly affects dogs.
A

Cataract

46
Q

Divisions of the Ear

A
  1. Inner or Internal Ear
  2. Middle Ear
  3. Outer or External Ear
47
Q

An elaborate system of membranous labyrinth filled with

A

endolymph

48
Q

Lies within the bony labyrinth excavated ftom the temporal bone and separated from it by
the perilymphatic space filled with

A

perilymph

49
Q
  • contains sense organs for hearing (cochlea) and detecting
    head acceleration (vestibular apparatus or vesticule), the latter is important in
    balance. Innervated by the cochlear and vestibular divisions of cranial nerve VIII.
A

Inner or Internal Ear

50
Q
  • contains bones (ossicles) that convey vibrations from the tympanic
    membrane (ear drum) to the inner ear.
A

Middle Ear

51
Q
  • channels sound waves to the tympanic membrane.
A

Outer or External Ear

52
Q

Parts of the Membranous Labyrinth

A
  1. Utricle
  2. Saccule
  3. Endolymphatic duct and sac
  4. Semicircular canals
  5. Ductus reuniens
  6. Cochlear duct
53
Q

At about 35 hrs of incubation in chick embryo, the surface ectoderm overlying the
dorsolateral wall of myelencephalon by _______, thickens to form a pair of auditory
or otic placodes

A

placode formation

54
Q

38 hrs of incubation, the otic placodes _____ to form auditory pits.

A

invaginate

55
Q

deepen to form an otic cup.

A

The otic pits

56
Q

gives off an evagination, the tubular
endolymphatic duct.

A

The dorsal wall

57
Q

At about 50 hrs of incubation the otic cup closes and separates from
the ectoderm (vesicle formation) forming an

A

otic vesicle (otocyst)

58
Q

is formed by apposition of endoderm of 1st pharyngeal pouch and
ectoderm of 1st branchial groove.

A

Tympanic membrane

59
Q

Dorsal part of forms the lining of
the ________auditory tube and tympanic cavity (in the horse a dilation of the auditory tube develops into
the guttural pouch)

A

the first pharyngeal pouch

60
Q

is derived from VA 1 and VA 2 (ectomesenchymal cells) flanking the 1st
branchial groove, that expand laterally.
.

A

pinna

61
Q

is composed of the nasal cavity, alae or wings, bridge, nostrils or anterior
nares, choanae or posterior nares, nasal septum and nasolacrimal duct.

A

The nose

62
Q

is the part of the nose that contains the nasal conchae. It is divided into
right and left chambers by the nasal septum

A

The nasal cavity

63
Q

Nasal placodes invaginate to form

A

olfactory or nasal pits.

64
Q
A

anterior nares

65
Q

Posterior opening of nasal pit ->

A

posterior nares.

66
Q

; the ectoderm

A

Nasal pit deepens to form the nasal cavity

67
Q

Depression between the lateral nasal process and the maxillary process of the visceral
arch 1 deepens to form the

A

nasolacrimal groove.

68
Q

closes over to form the nasolacrimal duct

A

The nasolacrimal groove

69
Q

closes over to form the nasolacrimal duct

A

The nasolacrimal groove

70
Q

are groups of specialized (chemoreceptive) epithelial cells localized
principally on the papillae of the tongue. Cranial nerve VII and IX innervate the taste
buds.

A

Taste buds