Part 1: Structure of Eye Flashcards
(48 cards)
1
Q
Outer layer of the eye consists of:
A
- sclera
- cornea
2
Q
Sclera:
A
- fibrous outer portion of the eye
- insertion for extraocular muscles
- continuous with the cornea
3
Q
The extraocular eye muscles insert onto the:
A
sclera
4
Q
Ciliary body:
A
- continuous with the choroid
- includes the ciliary muscle (for accommodation of the lens)
5
Q
Ciliary processes:
A
- secrete aqueous humor
6
Q
Iris:
A
- pigmented region which contains smooth muscle that controls the size of the pupil
7
Q
Optic disk:
A
- region of the retina from which all of the nerve fibers emerge to form the optic nerve
8
Q
Blind spot of the eye:
A
- at site of optic disk
- region of the retina where there are no photoreceptors
9
Q
The fovea is located where in the eye?
A
- pigmented region on the retina called macula lutea
10
Q
Is the optic nerve part of the CNS or PNS?
A
- CNS
- CNS diseases will affect vision and the optic nerve
- i.e. multiple sclerosis
11
Q
Blood supply to the retina:
A
- central artery of the retina
- central vein of the retina
- surrounded by optic nerve
- no collateral blood supply
12
Q
The optic nerve is surrounded by:
A
- subarachnoid space containing CSF
- dura
13
Q
What structures are medial to the fovea?
A
optic disk and optic nerve
14
Q
Increasing intracranial pressure via CSF may lead to what in the eye?
A
- impingement of the central artery and central vein of the retina.
- CSF surrounds the optic nerve, optic nerve surrounds the artery and vein
15
Q
The region posterior to the lens is the:
A
vitreous body.
16
Q
The region anterior to the lens contains:
A
- anterior chamber and posterior chamber
- both contain aqueous humor
17
Q
Anterior chamber location:
A
- between cornea and iris
18
Q
Posterior chamber location:
A
between iris and lens
19
Q
Structure, location, and function fo vitreous body:
A
- behind lens
- contains vitreous humor
- maintains architecture of eye to prevent the eye from collapsing in on itself
20
Q
Aqueous humor is secreted by:
A
- epithelial cells of the ciliary processes
21
Q
Aqueous humor pathway through eye from secretion to excretion:
A
- secreted into posterior chamber by ciliary processes
- passes through pupil into anterior chamber
- absorbed into venous channels in the Canal of Schlemm
22
Q
Canal of Schlemm:
A
- contains veins of the eye that absorb aqueous humor to maintain constant intraocular pressure
23
Q
Excess secretion of aqueous humor or inadequate drainage of aqueous humor will result in:
A
- increased intraocular pressure
- may lead to glaucoma
24
Q
Refraction of light occurs when light entering the eye passes through:
A
- cornea
- aqueous humor
- lens
- vitreous body
Ultimately, light ray focused on fovea.
25
The point of greatest refraction when light enters the eye is where?
cornea
26
What is the only site of light refraction in the eye that can be adjusted to alter refraction?
* the lens
* lens is altered in shape to ensure the light ray is focused on the fovea
27
Eye lens location:
* suspended from the ciliary body by the suspensory ligaments.
28
What controls the shape of the lens?
* Smooth muscle of ciliary muscle controls shape of lens by controlling shape of ciliary body.
29
Contraction of the ciliary muscle leads to:
* decrease in radius of ciliary body
* slackening of the suspensory ligaments
* lens becomes thicker due to intrinsic elasticity
* **_more refractive_**
30
What occurs when focusing on near objects?
* contraction of ciliary muscle
* leads to thickening of lens and more refractive power
31
Relaxation of the ciliary muscle causes:
* suspensory ligaments to stretch the lens
* lens becomes thinner and less refractive.
32
What occurs when focusing on distant objects?
* relaxation of ciliary muscle
* leads to thinning of lens and less refractive power
33
Presbyopia:
* loss of lens elasticity with age
* lens unable to become thicker when ciliary muscle relaxes
* near vision compromised
34
The three components of the accomodation reflex (to focus on near object):
1. relaxation of ciliary muscle (lens thickening)
2. convergence of eyes
3. pupillary restriction
35
The two divisions of the oculomotor nerve (CN3):
* superior division
* inferior division
36
The three branches of Trigeminal V1 (opthalmic division):
1. Frontal nerve
2. Lacrimal nerve
3. Nasociliary nerve
37
Contents of the Optic Canal:
1. Optic Nerve
2. Ophthalmic Artery
38
Contents of Superior Orbital Fissure:
1. Oculomotor Nerve (CN3; superior and inferior divisions)
2. Frontal nerve (V1 branch)
3. Lacrimal nerve (V1 branch)
4. Nasociliary nerve (V1 branch)
5. Trochlear Nerve (CN4)
6. Abducens Nerve (CN6)
7. Superior Ophthalmic Vein
39
Contents of Inferior Orbital Fissure:
* Inferior Ophthalmic Vein
* Infraorbital N. (V2)
* Zygomatic N. (V2)
40
Ophthalmic veins are what kind of veins?
* **emissary veins**
* communicate veins of the face, cavernous sinus and pterygoid venous plexus.
* spread of infection from face to brain
41
What nerve is closest to the internal carotid artery in the cavernous sinus?
* CN6 (abducens)
* symptoms will appear via this nerve first furing internal carotid aneurism in the cavernous sinus
42
The superior opthalmic vein is a continuation of:
* the cavernous sinus
43
Contents of the cavernous sinus:
* CN3
* CN4
* CN5-1 (V1)
* CN6
* Internal carotid artery
* cavernous sinus
* pituitary gland
44
The roof of the orbit is formed mostly by the:
* frontal bone
* related to frontal sinus and anterior cranial fossa
45
The floor of the orbit is formed mostly by the:
* maxilla
* related to maxillary sinus.
46
The medial wall of the orbit is formed mostly by the:
* ethmoid and sphenoid bones
* related to ethmoid air cells and nasal cavity.
47
The lateral wall of the orbit is formed mostly by the:
* zygoma and sphenoid bones
* related to infratemporal fossa and middle cranial fossa
48
Conjunctival sac structure:
* Palpebral Conjunctiva (anterior; on eyelid)
* Bulbar Conjunctiva (posterior; on eye)
