Ocular Anatomy (1st Ppt) Flashcards
1
Q
How much does an eyeball measure in diameter? [Answer in cm and in]
A
2.5cm (1in)
2
Q
How much of the anterior cavity is exposed?
A
1/6
3
Q
Mention the three layers of the wall of the eyeball:
A
1) Fibrous tunic
2) Vascular tunic
3) Nervous tunic
4
Q
T or F: The fibrous tunic is avascular
A
True
5
Q
What does the fibrous tunic consist of? [2]
A
1) Cornea
2) Sclera
6
Q
What is the cornea? [3]
A
- Transparent coat
- Curved
- Helps focus light onto retina
7
Q
What is the sclera? [3]
A
- White
- Gives shape to the eyeball
- Protects internal tissues
8
Q
The sclera covers the entire eyeball except for the _______.
A
Does not cover the cornea
9
Q
What is the fibrous tunic? [2]
A
- Superficial coat
- Dense fibrous connective tissue
10
Q
The junction of the sclera and cornea is an opening known as ______.
A
Canal of Schlemm
11
Q
What does the vascular tunic consist of? [3]
A
1) Choroid
2) Ciliary body
3) Iris
12
Q
Mention 5 characteristics of the choroid:
A
- Posterior
- Highly vascularized
- Lines the internal surface of the sclera
- Provides nutrients to the posterior surface of the retina
- Has some pigmented granules, but the line is not blunt like the RPE
13
Q
Mention 3 characteristics of the ciliary body:
A
- Continues from the choroid anteriorly
- Extends from the ora serrata to a point just posterior to the sclero-corneal junction [canal of schlemm]
- Muscles contracts & releases to see in far/close distances
14
Q
Mention 2 characteristics of Ciliary processes:
A
- Secretes aqueous humor
- Suspensory ligaments or zonular ligaments (attached to lens)
15
Q
Define ciliary muscles:
A
- Inside ciliary body
- Accommodation of lens
- Shifted the lens
16
Q
Mention 4 characteristics of the iris:
A
- Colored portion of the eyeball
- Center hole = pupil
- Melanocytes and smooth muscle (circular and radial muscles)
- Regulates amount of light entering
17
Q
Mention the eye cavities + their chambers
A
1) Anterior Cavity
- Anterior Chamber
- Posterior Chamber
2) Posterior Cavity
- Vitreous
18
Q
Mention 2 characteristics of the Retina. What tunic does it belong to?
A
- Third and inner coat of the eyeball
- Beginning of the visual pathway
–> Belongs to the nervous tunic
19
Q
How many layers does the retina have in total? Briefly describe them.
A
- Has 1 pigmented layer: Known as RPE (Retinal Pigment Layer). The melanin absorbs rays of light that enter the retina. *It’s not a neural layer
- Has 9 neural layers: all have neurological components
20
Q
What are the 3 main cells that compose the retina? Describe them
A
1) Photoreceptors
2) Bipolar cells
3) Gangliar cells
–> This is the specific part of the retina that sends information perceived to the optic nerve
21
Q
What are 4 characteristics of the lens?
A
- Posterior to the pupil
- Transparent
- Lacks blood vessels
- *Helps focusing images on the retina
22
Q
T or F. The lens does not divide the eyeball into 2 cavities.
A
False, it do.
23
Q
The lens divides the eyeball into 2 cavities, what are they?
A
1) Anterior Cavity
2) Vitreous chamber (posterior cavity)
24
Q
Mention 2 characteristics about the anterior cavity?
A
- Anterior to the lens
- 2 chambers filled with aqueous humor that contributes to the intraocular pressure
• Anterior chamber
• Posterior chamber
25
What is the Anterior chamber composed of?
Everything anterior to the lens
26
What is the posterior chamber composed of?
Iris- lens (including zonular fibers)
27
How often is the aqueous humor replaced in the body?
Replaced every 90 min
28
What is another name for suspensory ligaments? What is their function?
1) Zonular fibers
2) Dilate or constrict pupil on ciliary body's command
29
What are the characteristics of the Vitreous chamber and Vitreous itself? [4]
- Between lens and retina
- Vitreous
• Jelly-like substance
• Contribute to intraocular pressure
• Holds retina against choroid
• Even surface for the reception of clear images
30
What are the characteristics + functions of the eyelid? [4]
- Shade the eyes during sleep
- Protects the eyes from excessive light
- Protects eye from foreign objects
- Spread tears
- Upper eyelid is more movable
31
What does the eyelid consist of? [4]
- Skin
- Muscle
- Glands
- Conjuctiva
• Palpebral
• Bulbar
32
What is the palpebral fissure?
Space between upper and lower eyelid
33
What is the canthus? What other name does it have?
- Either of the angles of the eye [lateral or medial]
- Lateral / Medial commissure
34
What is the function of eyelashes and eyebrows?
Protection
35
What is the lacrimal apparatus? Mention its 5 structures.
A) Structures that produce and drain lacrimal fluid or tears
B) • Lacrimal glands
• Lacrimal ducts
• Lacrimal punctum
• Lacrimal canaliculi
• Lacrimal sac
36
What is the function of the Lacrimal sac?
Empties to the nasolacrimal duct
37
What are the 6 extrinsic muscles that move the eyeball?
- 4 rectus
• Superior
• Inferior
• Lateral
• Medial
- 2 obliques
• Superior
• Inferior
38
T or F. The fibrous tunic is vascularized.
False, the cornea nor sclera have blood. The nutrients are provided by vascular tunic.
39
What are 2 characteristics of the sclera?
- Densest and hardest structure of the eye
- White in color
- Gives protection from projectiles
40
What 3 structures of the Uvia?
Iris, Ciliary body, and choroid
41
What is the Ora serrata?
The jagged anterior margin of the retina
42
4 biggest components of the eye:
43
What are suspensory ligaments?
- Accommodates lens
- Attached to Ciliary body
44
What liquid does the ciliary body produce?
Aqueous humor
45
3 characteristics of the Schlemm Canal:
- Is considered a vein
- drains aqueous humor to veins *NOT TEARS
- does not drain blood
46
What does the limbus join?
- End of cornea with sclera
47
T or F. The lens is avascular.
True
48
Mention the 3 total avascular structures:
Cornea, sclera and lens
49
What is the macula?
- The center of vision (best vision) since it has the most cones of the retina [HD TV]
50
What eye disease does a white lens indicate?
Cataract
51
The aqueous humor goes through ___. Where does it drain? What is the function of it?
- Ciliary processes
- Sinus
- Nourishes the lens and cornea
52
What is the sclemm canal?
It's a circular canal in the limbus
53
T or F. All 5 layers of the cornea are avascular.
False, all layers are vascular.
54
Describe the 5 layers of the cornea.
1) Epithelium: outside layer; keeps things out
2) Bowman's layer
3) Stroma: Main component of the cornea & densest part
4) Descemet's membrane
5) Endothelium: forms cells & maintains metabolic activity
55
Mention 3 vascular eye structures:
-Iris: contracts
-Ciliary body: aqueous humor
-Choroid
56
Describe the dilator muscle. Mention its other name.
1) Dilates the eye (makes pupil bigger)
2) Mydriasis
57
Describe the sphincter muscle. Mention its other name.
1) It's a constrictor. Smaller pupil
2) Miosis [not to be confused with meiosis]
58
Choriod has both vessels:
Veins [oxygenated blood, brings blood in] and arteries [deox blood, takes out blood]
59
What are vortex veins?
Takes out all deox blood from the eye globe
60
T or F. Every fiber in the optic nerve is individual.
True
61
What is the episclera? [3]
- The only structural part of the sclera
- Only part of the sclera that has vessels [aka vascularized]
- It provides nutrients to sclera
62
Bruch's membrane: other name, what it is, and it's functions [2]
-Also called Lamina Vitrea
- It's a five layered extracellular membrane located between the retina [RPE] and choroid
- Requires elasticity to stretch & return to its size as intraocular pressure fluctuates, as well as accommodate changes in choriodal blood volume
63
Describe the conjuctiva: [4]
- Covers sclera and ends anteriorly to the limbus
- "It's like a sac in the front"
- Does not penetrate the posterior
- membrane must be moist
64
What is the function of the levator muscle?
Opens and closes eyelid
65
What does the lacrimal gland produce?
Tear film
66
What is the tear film composed of? [3]
1) Water- Moisture
2) Fat- delays evaporation of water
3) Mucus- Attaches tearfilm to the eye
67
What is the anterior pole? What is the posterior pole?
Anterior pole- Front of the eye, where the cornea is
Posterior pole- Back of the eye, where the optic nerve is
68
How is the equator of the eye?
Vertically center of the eye
69
The sandwich:
Outer --> Inner eye
Sclera, choroid, retina
SCE
70
Function of circular and radial muscles of the ciliary of processes [that control how much the iris open & closes]:
Circular: Constricts [Miosis]. Also called Sphincter muscle. the muscle of the
Radial: Dilates [Mydriasis]. Also called the dilator muscle.
