Histology of the Eye and Ear Flashcards
Tunics of the eyes
-briefly highlight structures within
Outer tunic:
- what is sclera, what does it transition to?
- transition zone called
what is this structure
- how does corneal epithelium anchor to next layer? which is?
- what is descemets’s membrane?
- characteristics or corneal endothelium
Cornea:
- where are myelinated nerves fround?
- when do they become unmyelinated?
- what does the stroma consist of?
- is the stroma vascular?
- what is the cornea permeable to?
- tarsal glands do what? blockage leads to?
- sebaceous glands (zeis)
- lacrimal gland: made up of?
- palpebral/bulbar conjuctiva: epithelium type, what space do they line
Embryology of the eye:
- where does optic vesicle form from?
- optic cup inner layer vs outer layer formations
- where does detached retina occur
- outer mesenchyme forms?
Chambers of the eye
Vascular coat:
- consists of?
- what is ciliary body?
- what muscle drives accomodation
- ciliary process function
- where does iris arise from?
- pupil contains what muscles
Aqueous humor and iridocorneal angle:
- how is aqueous humor secreted into posterior chamber
- how does it get into and out of the anterior chamber?
- glaucoma risk
Lens structure:
- suspended by what fibers?
- three components of lens?
- tension from ciliary body transmitted via?
- presbyopia?
- Cataracts?
distant vs close vision
both bowman’s membrane
what are the layers of the retina
What are the retinal layers?
Retinal layer:
- RPE type of epithelium rests on which membrane of the choroid?
- blood-neural retinal barrier?
- isomerization?
Rods and Cones:
- which are more sensitive
- classes of cone cells
- molecules in rods vs cones
- General structure: outer, inner, connections
Accomodation
Three components contribute to the accommodation process:
1.
The ciliary muscle.
2.
The ciliary body.
3.
The suspensory ligaments, inserted at the equatorial region of the lens capsule.
When the ciliary muscle contracts, the ciliary body moves toward the lens. Consequently, the tension of the suspensory ligaments is reduced, and the elastic capsule of the lens enables the lens to acquire a spherical shape. A rounded lens facilitates close vision.
When the ciliary muscle relaxes, the ciliary body keeps the tension of the suspensory ligaments that pull at the circumference of the lens. Thus, the lens remains flat to enable distant vision. This condition is known asemmetropia (Greek emmetros , in proper measure; opia , pertaining to the eye), or normal vision.
If the eyeball is too deep or the curvature of the lens is not flat enough, the image of a distant object forms in a plane in front of the retina. Distant objects are blurry because they are out of focus, but vision at close range is normal. This condition is called myopia (Greek myein, to shut), or nearsightedness.
If the eyeball is too shallow and the curvature of the lens is too flat, the distant image is formed at a planebehind the retina. Distant objects are well resolved but objects at a closer range are not. This condition is called hyperopia (Greek hyper, above), or farsightedness.
Older people become farsighted as the lens loses elasticity. This form of hyperopia is known as presbyopia(Greek presbys , old man).
Accommodation difficulties can be improved by the use of lenses. A diverging lens corrects myopia; a converging lens corrects hyperopia.
Clinical significance of detached retina
The clinical significance of the detachment of the nonsensory retinal pigmented epithelium from the sensory retina is highlighted by the following functions of the pigmented epithelium:
1.
The transport of nutrients from the choroidal blood vessels to the outer layers of the sensory retina.
2.
The removal of metabolic waste products from the sensory retina.
3.
Active phagocytosis and recycling of photoreceptor disks shed from the outer segment of the cones and rods.
4.
The synthesis of basal lamina components of Bruch’s membrane to which the retinal pigmented epithelium is firmly attached.
5.
It is essential for the formation of the photopigment rhodopsin because it regenerates the bleached photopigment by converting all -trans retinol into retinal, which is returned to the photoreceptor byinterstitial retinoid-binding protein (IRBP) , a major protein in the interphotoreceptor matrix
Retinoblastoma:
- inheritance pattern what gene/chromosome
- what is gene supposed to do
- clinical features
Parts of ear overview
-outer, middle, inner
