Histology of the Eye and Ear Flashcards
1
Q
Special sebaceous glands whose secretion retards evaporation of tears
A
Tarsal (meibomian) glands
2
Q
Blockage of Tarsal (Meibomian) glands leads to _______, or inflammation of the gland
A
Chalazion
3
Q
Infections of these glands causes a “stye”
A
Sebaceous (Zeis) gland of eyelashes
4
Q
Gland that produces tears; located beneath the conjunctiva
A
Lacrimal gland
5
Q
The lacrimal gland is made up of ____ ____ glands; approximately 12 ducts empty beneath the upper lid; drains into ______ duct
A
Tubuloacinar serous
Nasolacrimal
6
Q
2 types of conjunctiva lining the space between the inner eyelid and ending just lateral to the cornea
A
Palpebral conjunctiva
Bulbar conjunctiva
7
Q
The palpebral and bulbar conjunctiva are made up of thin mucous membrane with _____________ epithelium + _____ cells
A
Stratified columnar; goblet
8
Q
Development of the eye begins with evagination of _______ from the forebrain, forming the _____ _____
A
Neuroectoderm; optic vesicles
9
Q
Invagination of the optic vesicle forms the ____ _____, connected to the forebrain by an ____ ____
A
Optic cup; optic stalk
10
Q
Optic vesicles induce overlying ______, forming a lens vesicle located within the cup
A
Ectoderm
11
Q
The inner layer of the optic cup forms the ____ _____
The outer layer of the optic cup forms the ____ ____ ____
A
Neural retina
Retinal pigmented epithelium
12
Q
The inner layer of the optic cup forms the neural retina while the outer layer forms the retinal pigmented epithelium. What 3 things does the outer mesenchyme form?
A
Choroid
Sclera
Cornea
13
Q
What is formed by the rim of the optic cup
A
Iris
Ciliary body
14
Q
Ectoderm overlying the lens vesicle forms the lid and ______ ____ ____
A
Outer corneal epithelium
15
Q
During eye development, blood vessels enter via a groove called the ___ ___
A
Optic fissure
16
Q
What is the site where detached retina occurs?
A
Inner/outer optic cup layers
17
Q
3 basic layers of the eye from outer to inner
A
Corneosclera
Vascular coat (uvea)
Retina
18
Q
The corneoscleral layer of the eye is the outer fibrous coat, and is penetrated by the _____ n.
It consists of the sclera and retina
A
Optic
19
Q
Composition of the sclera
A
Dense CT
20
Q
What part of the corneoscleral layer of the eye do extrinsic mm attach to?
A
Sclera
21
Q
The anterior surface of the cornea is transparent and continuous with the _____
A
Sclera
22
Q
3 components of the vascular coat (Uvea) layer of the eye
A
Choroid
Stroma of ciliary body
Stroma of iris
23
Q
Describe function of choroid contained in vascular coat (uvea) layer of the eye
A
Heavily pigmented; absorbs scattered light
Rich blood vessels lined with fenestrated capillaries for providing nutrients to retina
Well-attached to retina
24
Q
Which part of the vascular coat (uvea) of the eye contains the ciliary mm responsible for accommodation?
A
Stroma of ciliary body
25
Function of stroma of iris (part of vascular coat/uvea layer of eye)
Contractile diaphragm where pupil is central aperture
26
The inner coat of the eye is the retina, which rests on the _____
Choroid
27
3 components of the retina layer of the eye
Epithelium of ciliary body and iris
Neural retina
Retinal pigmented epithelium (RPE)
28
Function of neural retina
Contains photoreceptors and support cells
29
4 primary functions of retinal pigmented epithelium (RPE) in retina layer of eye
Absorbs light
Prevents reflections
Major component of blood-retinal barrier
Phagocytosis
30
3 chambers of the eye
Anterior chamber
Posterior chamber
Vitreous (body) chamber
31
The anterior chamber of the eye is the space between the ____ and ____
Cornea; iris
32
The posterior chamber of the eye is the space between the posterior surface of the ______ and the anterior surface of the ______
Iris; lens
33
The vitreous chamber of the eye is the space between the posterior surface of the _____ and the ____ ____
Lens; neural retina
34
The vitreous chamber of the eye is filled with ____ ____ to help maintain its shape; it is made up of 99% water with proteins and hyaluronan
Vitreous humor
35
_____ = thick fibrous opaque layer pierced by blood vessels and posteriorly by optic n.
Sclera
36
Chief refractive element of eye that is continuous with sclera, made up of 5 layers
Cornea
37
5 layers of cornea from superficial to deep
```
Corneal epithelium
Bowman’s membrane
Corneal stroma
Descemet’s membrane
Corneal endothelium
```
38
Corneal epithelium type
Nonkeratinized stratified squamous
39
Stem cells for the corneal epithelium are located in the ____ region
Limbus
40
Anterior basement membrane for corneal epithelium
Bowman’s membrane
41
Describe orientation of cells in corneal stroma, as well as its vascularization
Unique orientation of cells and stroma
Avascular
42
Very thick posterior basement membrane for corneal endothelium
Descemet’s membrane
43
Corneal endothelium type
Simple squamous epithlium facing the anterior chamber
44
T/F: the corneoscleral coat is not innervated
False; it is well innervated with afferent nerves extending to the surface
45
The vascular coat of the eye consists of what 3 components?
Choroid
Ciliary body
Iris
46
The choroid of the vascular coat consists of an inner vascular layer (choriocapillary) and ______ membrane which is a thick amorphous ECM layer
Bruch’s
47
The _____ ____ is comprised of 17-34 thickened ridges of anterior vascular coat located between the iris and choroid
Ciliary body
48
Smooth muscle originating at corneoscleral junction; drives accommodation of the lens
Ciliary muscle
49
Function of ciliary processes in vascular coat of eye
Secretion of aqueous humor and formation and anchoring of zonular fibers forming suspensory ligament of the lens
50
_____ forms the contractile diaphragm in front of the lens
Iris
51
The iris arises from the anterior border of the ____ _____; the pupil is the central aperture.
It contains ______ (radial band) and ______ ______ (circular band) mm., as well as posterior pigmented epithelium
Ciliary body
Dilator; sphincter pupillae
52
Aqueous humor is secreted into the ____ chamber by ciliary processes.
Fluid passes through the pupil to enter the ______ chamber. Excess fluid is taken up by ____ _____, aka the trabecular network and canal of Schlemm
Posterior
Anterior; limbus apparatus
53
Named angle between the sclera/iris and ciliary muscle seen on histological slide
Iridocorneal angle
54
Functions of aqueous humor
Provides nutrients and oxygen to avascular structures and maintains ocular shape
55
Risks of excess aqueous humor production
Increased intraocular pressure, may lead to glaucoma
56
The lens is a transparent, bi-concave structure suspended by _____ fibers
Zonular
57
3 components of lens
Capsule
Subcapsular lens epithelium
Lens fibers
58
Composition of lens capsule
Flexible, elastic ECM
59
Cells on the periphery of the subcapsular lens epithelium proliferate and migrate to make mature lens fibers cells.
What happens to the rate of this proliferation/migration with age?
Decreases
60
Describe composition of lens fibers cells
Filled with crystallins (all organelles are lost)
Central lens nucleus laid down during embryonic/fetal development
61
Lens accomodation is provided by tension from ciliary body, transmitted via ______ fibers, thus changing lens shape
Zonular
62
Condition characterized by loss of lens elasticity with age
Presbyopia
63
Condition characterized by loss of transparency of lens or capsule
Cataracts
64
The retinal pigmented layer is a layer of ______________ epithelial cells resting on _____ membrane of the choroid
Simple cuboidal; Bruch’s
65
3 primary functions of retinal pigmented layer
Serves as blood-neural retinal barrier (from choroid) — absorbs stray light
Phagocytoses membranous discs shed from rods and cones
Isomerizes all-trans RA to 11-cis RA, transporting it back to photoreceptors
66
What layer of the retina contains photosensory cells but does not contain lymphatics?
Neural retina
67
Blind spot in retina where optic nn from ganglion layer exit the eye
Optic disc
68
10 layers of retina
1. RPE (not part of neural retina)
2. Rod/cone ends of photoreceptors
3. Outer limiting membrane
4. Outer nuclear layer
5. Outer plexiform layer
6. Inner nuclear layer
7. Inner plexiform layer
8. Ganglion layer
9. Layer of optic n. fibers
10. Inner limiting membrane
69
Which retinal layer serves as the apical boundary of Muller cells (row of zona adherens attaching apical ends of Muller cells)?
Outer limiting membrane
70
Which retinal layer contains cell bodies (nuclei) of photoreceptor cells?
Outer nuclear layer
71
Which retinal layer contains processes of rods/cones, as well as the horizontal, amacrine, and bipolar cells connecting them?
Outer plexiform layer
72
Which retinal layer contains cell bodies of horizontal, amacrine, and bipolar cells, as well as the nuclei of muller cells?
Inner nuclear layer
73
Which retinal layer contains processes of interconnecting ganglion, amacrine, bipolar, and horizontal cells?
Inner plexiform layer
74
Which retinal layer contains cell bodies (nuclei) of ganglion cells?
Ganglion layer
75
Which retinal layer contains processes of ganglion cells?
Layer of optic nerve fibers
76
Which retinal layer forms the inner limiting membrane of Muller cells?
Inner limiting membrane
77
Which are more numerous - rod cells or cone cells?
Rod cells
120 million rod/7 million cone photoreceptor cells
78
Which are more sensitive - rod cells or cone cells?
Rod cells
79
3 classes of cone cells
Blue
Green
Red
80
Area of highest concentration of cones; avascular; and surrounded by macula lutea
Fovea centralis
81
In terms of visual pigments, rods have ______, and cones have ______
Rhodopsin; iodopsin
82
General structure of rods and cones
Outer segment: photosensitive part comprised of series of plasma membrane discs; discs connected to inner segment via modified cilium; discs shed during normal functioning; phagocytosed by RPE cells
Connecting stalk: contains basal body of cilium
Inner segment: major organelles
83
Autosomal dominant genetic disorder caused by a mutation in the Rb gene on chromosome 13q14.1
Retinoblastoma
84
What type of gene is Rb
Tumor suppressor gene (G1–>S transition in cell cycle)
85
Clinical features of retinoblastoma
Malignant tumor of retina that develops in children younger than 5
Leukocoria (white pupil) — abnormal white light reflection off retina
Strabismus — misalignment of eyes
86
Auditory portion of inner ear
Cochlea
87
What are the 3 components of the vestibular portion of the inner ear?
Semicircular canals, utricle, saccule
88
The _____ _____ is what interconnects the cavities and canals within inner ear bones, including semicircular canals, vestibule (saccule+utricle), and cochlea
Bony labyrinth
89
The _____ _____ lies within the bony labyrinth and consists of small sacs and tubules forming continuous spaces enclosed by an epithelium
Membranous labyrinth
90
3 spaces associated with membranous labyrinth of inner ear
Endolymphatic space: within membranous labyrinth
Perilymphatic space: between bony and membranous labyrinths
Corticolymphatic space: lies within organ of Corti
91
Spiral space within bone containing cochlear duct
Cochlear canal
92
The ____ ____ divides cochlear canal into 3 parallel soft tissue-lined compartments.
What are the 3 compartments?
Cochlear duct
3 compartments:
Scala media
Scala vestibule
Scala tympani
93
The scala media (cochlear duct) is the middle compartment which contains _______
It consists of the ____ ____, which is the lateral wall of scala media and the source of the above substance
Endolymph; stria vascularis
94
Turnover of endolymph in the scala media involves resorption into what structures via the endolymphatic duct and sac?
Dural venous sinuses
95
The scala vestibule contains ______ moved by the stapes at the ____ window; it is continuous with the scala tympani
The scala tympani is connected to the ____ window
Perilymph; oval
Round
96
What specialized structure is found on the floor of scala media resting on the basilar membrane?
Organ of corti
97
Inner spiraling bony shelf serving as support for tectorial membrane and spiral ganglia
Outer spiral lamina (OSL)
98
Composition of organ of corti
Hair cells (sensory)
Inner and outer phalangeal cells (support for hair cells)
Pillar cells (support between basilar membrane and tympanic lip)
99
In the organ of corti, there are 3 rows of outer hair cells and a single row of inner hair cells.
_____ of hair cells is embedded in overlying _____ membrane extending from the spiral lamina
Basilar membrane vibrates with sound, causing deflection of these structures; this is what initiates neural transduction carried by the ____ n.
Stereocilia; tectorial
Cochlear
100
Path of sound waves
Sound waves enter ear and cause TM to vibrate
TM vibration moves auditory ossicles; sound waves amplified
Stapes at oval window generates pressure waves in perilymph within scala vestibuli
Pressure waves cause vestibular membrane movement —> pressure wave formation in endolymph in cochlear duct and displacement of hair cells in organ of corti, initiating nerve signal in cochlear branch of CN VIII
Remaining pressure waves are transferred to scala tympani and exit inner ear via round window
101
The 3 semicircular canals are oriented in 3 axes. They are filled with ______ and are connected to utricle. Ends of canals have ______ with gelatinous-like cap called a cupulla (innervated hair cells with stereocilia are attached here).
The _____ is displaced by fluid motion within canal which serves as sensor of rotational velocity
Endolymph; ampullaris
Cupulla
102
The vestibule contains the ____ and _____.
Of these structures, each contain a ________ which is comprised of clusters of hair cells with stereocilia with overlying gelatinous material called the ______ membrane. This membrane is covered with calcium carbonate/protein crystals called _______.
This serves as sensor for gravity and ______ acceleration
Utricle; saccule
Macula; otolithic; otoconia
Linear
103
3 parts of audio-vestibular system
Outer ear
Middle ear
Inner ear
104
3 sensory systems in audio-vestibular system
Audition
Rotational velocity
Gravity/linear acceleration
105
3 nerves in internal acoustic meatus
Vestibular n.
Acoustic n.
Facial n.
106
How many maculae are present in the audio-vestibular system?
Only TWO maculae, responsible for detecting linear acceleration in THREE dimensions
