Eye and Ear Flashcards
1
Q
Structure of the eye
A
3 layers
- Outer layer (CT layer) = Tunica Fibrosa
- Sclera = CT
- Conea - Uvea
- Choroid - vascular layer which provides nutrients to the retina
- ciliary body
- Iris - Retina (innermost part)
- consists of rods and cones and neruons that will become the optic nerve
- mainly nerual (5/6)
- non neural retina lines the ciliary body and the iris
2
Q
Tunica Fibrosa
A
- outermost layer
- fibrous layer
- Sclera - covers most of the back of the eye
- Cornea - in contact with air on one side and fluid on the other
3
Q
Sclera
A
- CT layer
- acting as a capsule to hold the eye in place
- has typical CT materials - fibroblasts, amorphous components, etc.
4
Q
Cornea
A
- Has 5 layers
1. corneal epithelium (outermost layer)
- Bowman’s membrane
- thick layer of extracellular material
- noncellular - Stromal layer
- thickest layer - Descemel’s membrane
- Endothelium Layer
- squamous
Light must pass through all 5 layers of cornea before it gets inot the anterior chamber
5
Q
Canal of Schlemn
A
- Facilitates equilibrium of pressure within the eye
- Equilibrates the pressure in the anterior chamber
- if you have pressure that builds up in the anterior chamber, it can drain out through this canal
6
Q
Uvea
A
3 layers
- choroid - vascular
- ciliary body
- iris
7
Q
Choroid
A
- Blood vessels providing nutrients to the sclera (CT) and the retina
Choriocapillary layer - close to the retina
- subdivision of choroid
- blood vessels are much smaller - filled with capillaries
- immediately adjacent to the retina
8
Q
Ciliary Body
A
- contain muscle that can contract and change shape of lens for visual accommodation
- folds of epithelium = ciliary processes
- from the processes, you have zonule fibers
- by changing the shape of the muscle, you will pull or relax on the lens to change its shape for visual acuity
9
Q
Ciliary Processes
A
- Contain a double layer of low columnar to cuboidal epithelium
- Inner layer is pigmented with melanin granules
- outer layer is non pigmented
10
Q
Iris
A
- Double layer of epithelium continues from the ciliary processes to line the posterior iris
- eye color is due to amount of pigment in the epithelium
11
Q
Zonule Fibers
A
- from the ciliary processes, you get zonule fibers attached to the lens
- oxytalin fibers - first component of elastic fibers
- bridge between ciliary body and lens
- Pull on the lens - change lens shape
12
Q
Vitreous Chamber
A
- like a sponge
- a lot of hyaluronic acid
- glycosaminoglycans - hyrophobic - absorb a lot of water
- -holds a lot of water
13
Q
Retina
A
5/6 of the back of the eye ball is neural retina
forward 1/6 is non neural
- double layer epithelium that projects forward to line the ciliary body and iris
14
Q
3 Layers of the Retina
A
- Outer most/ deepest layer
- consists of rods and cones embedded in pigmented epithelium
- receive photons of energy in the form of light
- stimulate some visual stimulus - Bipolar neurons
- one side on the rods and cones
- the other on a ganglian cell
- Muller cell - sustantacular cell (support cell) - Ganglain Cell layer
- one end attaches to the bipolar neuron layer
- the other end forms axons and project to become the optic nerve
15
Q
Ora serrata
A
- Transition form the neural retina to the non neural retina
- non neural is double layer epithelium that lines the ciliary body and back of the iris
16
Q
Rods
A
- most sensitive to light
- only give you black, white and shades of grey
- Rhodopsin - responsible for perceptions of black, white and grey
- under low light conditions, the rods are able to pick up light that the cones cannot
17
Q
Cones
A
- give you color vision
- have iodopsin - gives perceptions of color
- cones need a good bit of light to be stimulated
- in the light they are able to pick up more photons of light
18
Q
Fobea Centralis
A
- macula
- only cones
- located at the back of the eyeball
- responsible for central vision and visual acuity
19
Q
Optic Nerve
A
- blind spot
- central artery of the retina runs through the optic nerve
- no rods or cones
20
Q
Lens
A
- outermost layer is lens capsule - CT, non cellular
- lens epithelium - simple cuboidal to columnar
- Differentiating lens fibers
- mature lens fibers
- light has to go through all of these layers plus the anterior chamber before reaching the rods and cones
21
Q
Eyelid
A
Innermost layer is the conjunctiva
- in contact with the eye ball
- layer of epithelial cells
Tarsal plate gives rigidity to the eye
- so you can move your eye
Meibomian Gland
- sebaceous glands
Orbicular Muscle
- contract to allow movement of the eye
Eyelashes
- prevents things from getting in the eye
22
Q
Conjunctiva
A
- Layer in contact with part of the eyeball
- predominantly stratified columnar to stratified squamous
23
Q
Lacrimal Apparatus
A
Lacrimal Gland
- produces tears
- secretes fluid onto the eye
24
Q
Extraocular Muscles
A
- Pull on the eye to that it can move around and to focus
25
Q
Structure of the Ear
A
3 Layers
- Outer ear
- eardrum - Middle ear
- articulating bones
- create a sound wave for inner ear - Inner ear
- cochlea (hearing)
- vestibular apparatus (balance and motion)
26
Q
Pinna
A
- Contains a lot of CT and elastic fibers
27
Q
External Auditory Meatus
A
- ear canal
- lined by epidermis
- Continuous with the ear lobe
- contains the ceruminous glands - gives rise to ear wax
28
Q
Tympanum
A
- Tympanic membrane (eardrum)
- 3 layers
1. Epidermis continuous with the canal
2. middle layer of fibrous CT
3. Inner layer of simple cuboidal and/or squamous
29
Q
Middle Ear
A
Malleus, incus, and stapes
- articulating bones
- transmit a sound wave from eardrum to the oval window
- when they articulate, they amplify the signal of sound
- stapes has a pad that pounds on the oval window of the inner ear
30
Q
Bony and Membranous Labyrinth
A
Bony Labyrinth
- bone “shell” around the membranous labyrinth
Membranous labyrinth
- the tissue within the bony labyrinth
- nerves are quite large and attach to the three components of the inner ear
31
Q
Inner Ear Sensory Regions
A
Vestibular Apparatus
- utricle and the saccule
- maculae is the sensory structure within - responsible for the perception of motion
Semicircular canals
- 3 of them in different orientations (x,y,z)
- cristae ampullares - responsible for 3D orientaion and motion
Cochlea
- Oran of Corti - responsible for hearing
32
Q
Cochlea
A
- sea shell shaped
- Oval window is being baned on by the stapes
- pressure wave passes down through cochlea
- causes the organ of Corti to vibrate, causing sensation of sound
- pressure goes back down and pushes on the round window
- vibration of the tectorial membrane is responsible for stimulating the hair cells of the of the organ of corti
33
Q
Middle Duct of Cochlea
A
- called scala media
- organ of corti is on the scala media
- one the back of the scala media, there is a layer of cells called the scala vascularis - secrete endolymph (maintains the viability of the cells of the organ of corti)
- surrounded by vesibular membrane
34
Q
Organ of Corti
A
- As the fluid within the canal is pushed by a pressure wave the tectorial membrane rubs against the hair cells
- vibrating due to sound creating a pressure wave
- the hair cells perceive the movement of tectorial membrane
- projects that on the cochlear nerve which then goes to the auditory nerve which is how you hear
35
Q
Stereocilia Bundles
A
- Hair cells - in a v shaped row
- Tectorial membrane rubbing on the hair cells transduces a signal perceived as sound
36
Q
Vestibular Apparatus
A
- within the utricle and the saccule there is a sensory structure called the macula
37
Q
Macula
A
- contains stereocilia and one long true cilia
- embedded in a gelatinous layer - has calcium carbonate crystals on top of it - otoliths or otoconia
- otoliths provide for inertia
- cilia and stereocilia bend with the movement of the gelatinous layer which provides for perception of linear acceleration
- sensory cells containing stereocilia and one true cilia at the end of the escalating ramped up bundle of stereocilia
38
Q
Cristae Ampullares
A
- at the base of semicircular canals perceive rotation
- The gelatinous layer rubs against the other side of the canal
- inertia is provided by the rubbing against the other side of the canal
39
Q
Semicircular canals
A
- canals are in X, Y, Z orientation allowing for perception of rotation
