Lecture 8: Histo Of Eye & Ear

Question 1

What makes up the outer, middle and inner tunics of the eye?

Answer 1

Outer tunic = sclera and cornea

Middle tunic = uvea

Inner tunic = retina

Question 2

The __________ is the zone of transition of the epithelium of the conjunctiva with that of the cornea. This is also the boundary of the transparent cornea with the opaque sclera

Answer 2

Limbus

Question 3

What are the layers of the cornea from outer to inner?

Answer 3

Corneal epithelium -> Bowman’s layer -> stroma -> Descemet’s membrane -> corneal endothelium

Question 4

The stroma of the cornea is formed by _____________ oriented at an angle to one another. _____________, surrounded by ECM are present between these.

Answer 4

Collagen lamellae; fibroblasts

Question 5

T/F: Blood vessels are not present in the stroma of the cornea

Answer 5

T

Question 6

Where are myelinated versus unmyelinated nerves found in the cornea of the eye?

Answer 6

Myelinated nerves can be found in the stroma but become unmyelinated after crossing Bowmans layer, extending toward the surface in the intercellular spaces of the corneal epithelium

Question 7

What is the most common form of tissue allotransplantation with a success rate of over 90%?

Answer 7

Cornea transplant (penetrating keratoplasty)

Question 8

In the posterior 2/3 of the eye, the vascular layer is called the ___________. In the anterior part of the eye the vascular layer thickens to form the ____________.

Answer 8

Choroid; ciliary body

Question 9

What 3 major structures compose the uvea of the eye?

Answer 9

Choroid
Ciliary body
Uvea

Question 10

What attaches the ciliary muscles of the ciliary body to the lens of the eye?

Answer 10

Zonular fibers

Question 11

What does contraction of the ciliary muscles of the ciliary body do?

Answer 11

Relaxes the tension exerted by the zonular fibers on the lens and focuses the image that you are looking at

Question 12

What produces the aqueous humor of the eye?

Answer 12

The ciliary epithelium lining the ciliary processes which project from the ciliary body

Question 13

Where is epithelium found on the iris of the eye?

Answer 13

The iris has 2 surfaces. The anterior surface lacks an epithelial lining. The posterior surface is lined by a dual layer of pigmented epithelial cells (direct continuation of the pigmented layer of the retina)

Question 14

What does the stroma of the iris contain?

Answer 14

Melanocytes and myoepithelial cells forming the dilator pupillae

Question 15

The _________ pupillae consists of smooth muscle cells, has Ach receptors, and causes pupil constriction. The __________ pupillae consists of myoepithelial cells, contains alpha adrenergic recetors and causes pupil dilation.

Answer 15

Sphincter pupillae; dilator pupillae

Question 16

What are the layers of the retina in order from the outer region to the inner region?

Answer 16

1) pigmented epithelium
2) Inner and outer segments of rods and cones
3) Outer limiting membrane
4) Outer nuclear layer
5) Outer plexiform layer
6) Inner nuclear layer
7) Inner plexiform layer
8) Ganglion cell layer
9) Nerve fiber layer (axons of ganglion cells)
10) Inner limiting membrane

Question 17

What cell types are found in the inner nuclear layer of the retina?

Answer 17

Bipolar cells
Amacrine cells
Horizontal cells
Muller cells

Question 18

At the ____________ of the retina, tightly packed cones are arranged at an angle to the pigmented layer. Consequently, the outer nuclear layer and the other layers of the sensory retina dont obstruct the light pathway

Answer 18

Fovea centralis

See the best here

Question 19

Where in the retina are there the highest concentration of cones?

Answer 19

Fovea centralis -> cones are for seeing color, therefore this isnt the best spot for seeing things in the dark

Question 20

The axons of the ganglion cells of the retina turn into the optic nerve at the ______________, which lacks photoreceptors and corresponds to the blind spot of the retina

Answer 20

Optic Disk

**Worse place to see

Question 21

The ___________________ is a yellow spot on the retina produced by xanthophyll pigments within retinal cells which may absorb short wavelength light and provides for central vision

Answer 21

Macula lutea

Question 22

What are the 3 different types of photopigment sensitive cone populations of the retina?

Answer 22

Blue, green, or red -> when a single group of color-receptive cones is missing, the individual cant distinguish some colors from others, hence color blindness

Question 23

The ___________ and ___________ chambers of the eye contain aqueous humors, whereas the ___________ cavity contains a gelatin body which gives the eyeball its shape

Answer 23

Anterior and posterior chambers; vitreous cavity

Question 24

What are the 3 steps of the flow of aqueous humor in the eye?

Answer 24

1) aqueous humor produced by the epithelial lining of the ciliary processes
2) Aqueous humor flows from posterior chamber through pupil to anterior chamber, then through the trabecular meshwork and finally into the canal of Schlemm
3) Aqueous veins drain the canal of schlemm into the episcleral veins

Question 25

Explain glaucoma

Answer 25

Obstruction of aqueous humor that causes an increase in intraoccular pressure. Produces pain and nausea. Either by blockage of canal of Schlemm (most common) or inflammation preventing aqueous humor from reaching the trabecular meshwork

Question 26

Explain cataracts

Answer 26

Opacity of the lens of the eye caused by change in the solubility of lens proteins. Impairs vision and is usually the result of aging and diabetes

Question 27

Explain red eye

Answer 27

Subconjunctival hemorrhage (bleeding under conjunctiva) and conjunctivitis

Question 28

Where is endolymph found?

Answer 28

Utricle, saccule and the semicircular canals of the inner ear

Question 29

Where is perilymph found?

Answer 29

Scala tympani and scala vestibuli

Question 30

The space where the scala vestibuli and scala tympani come together is called the ____________

Answer 30

Helicotrema

Question 31

What is the difference in attachment between the inner and outer hair cells of the cochlea?

Answer 31

Inner are free floating

Outer are attached to tectorial membrane

Question 32

Endolymph has a high _____ content and perilymph has a high _____ content

Answer 32

K+; Na+

Question 33

A “stye” is an infection of what gland in the eye?

Answer 33

Sebaceous (Zeis) gland of eyelashes

Question 34

What layer of the retina is responsible for isomerizing all-trans retinal to 11-cis retinal and transporting it back to photoreceptors?

Answer 34

Retinal pigmented layer

Question 35

What type of epithelium lines the respiratory mucosa?

Answer 35

Pseudostratified columnar ciliated epithelium

Question 36

Describe lining mucosa of the oral cavity and where its found

Answer 36

• Soft surface texture, moist and ability to stretch
• Nonkeratinized stratified squamous epithelium
• FOund on ventral surface of tongue, soft palate, floor of mouth and makes up buccal, labial and alveolar mucosa

Commonly has underlying submucosa

Question 37

Explain masticatory mucosa of the oral cavity and where its found

Answer 37

• Rubbery surface with good resiliency
• Keratinized stratified squamous epithelium
• found on hard palate, attached to gingiva and dorsal surface of tongue

**Thin or absent submucosa

Question 38

Where is specialized mucosa of the oral cavity found?

Answer 38

On dorsal and lateral surfaces of the tongue in the form of lingual papillae

Question 39

WHat type of tonsil has a thin underlying capsule, invaginate mucosa with shallow ingoldings and no crypts?

Answer 39

Pharyngeal tonsil

Question 40

Where are pharyngeal tonsils located and what type of epithelium covers them?

Answer 40

Single structure along posterior wall of nasopharynx; pseudostratified columnar ciliated epithelium

Question 41

What type of tonsil has deep crypts, contains germinal centers and has dense CT that acts as a partial capsule?

Answer 41

Palatine tonsil

Question 42

Where are palatine tonsils located and what type of epithelium covers them?

Answer 42

Positioned bilaterally in oropharynx; stratified squamous epithelium

Question 43

What type of tonsil has germinal centers with varying number of crypts and lacks a distinct capsule?

Answer 43

Lingual tonsil

Question 44

Where are lingual tonsils located and what type of epithelium covers them?

Answer 44

Positioned along base of tongue; stratified squamous epithelium