Vision I Flashcards

1
Q

We each have ___ eyes
Eyes contain __% of the body’s sensory receptors
You only see ___of the eye’s total surface

A

2
70%

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2
Q

The rest of the surface of the eye is in the orbit, which is composed of how many bones?

A
7: Frontal
Lacrimal
Ethmoid
Zygomatic
Maxillary
Palatine
Sphenoid
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3
Q

How is information from the eyes transmitted to the brain?

A

Via the optic nerve, or Cranial Nerve II

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4
Q

What is a commissure?

A

Where eyelids meet

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5
Q

What is the lacrimal caruncle?

A

A little bit of flesh on the medial commissure.

Contains sebaceous and sweat glands

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6
Q

What are the three functions of the eyelid?

A

1-To shade the eye
2-Protects the eye
3-Eyelid spreads lubricating tears across the eye

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7
Q

What is the palpebral fissure?

A

The area between eyelids

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8
Q

What is the sclera?

A

The white part of the eye, goes around the eyeball

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9
Q

What is the palpebral conjunctiva?

A

Covers the inside of the eyelid

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10
Q

What is conjunctiva?

A

A thin, transparent protective mucus membrane

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11
Q

What type of cells compose the conjunctiva?

A

Stratified epithelium

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12
Q

The conjunctiva is very ______ and can cause bloodshot eyes and is richly ________, which makes it sensitive to pain

A

vascular

innervated

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13
Q

What is conjunctivitis and what causes it?

A

Inflammation of conjunctiva
Aka: “Pink-Eye”
Can be caused by bacteria, viruses, allergens, or irritants

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14
Q

The bulbar conjunctiva covers the _______, while the palpebral conjunctiva covers the ________.

A

Eyeball

Eyelid

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15
Q

Eyelashes protect the eyes from these three things:

A

perspiration
foreign objects
direct rays of sun

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16
Q

What is the name of the sebaceous gland at the base of each eyelash?

A

Gland of Zeis

17
Q

What is the function of the Zeis gland?

A

Zeis glands make lubricating fluid,

18
Q

An infection of the Zeis gland is a ______.

A

stye

19
Q

What is the lacrimal gland?

A

A small gland medial to the eye, that create tears

20
Q

What is the excretory lacrimal duct? How many are there?

A

Ducts that transport tears to the conjunctiva. There are 6-12 per side.

21
Q

What is the inferior nasal meatus?

A

A space below the inferior nasal conchae in palatine bone, through which tears travel to the sinuses. This connects the eye to the nose.

22
Q

What are tears?

A

Make 1 mL a day, are a solution of mucus, salts and lysozyme (an antibacterial)

23
Q

What are the six extrinsic eye muscles?

A
Medial Rectus
Superior Rectus
Superior oblique
Lateral Rectus		
Inferior Rectus		
Inferior Oblique
24
Q

Describe the recti and oblique muscles in general.

A

4 recti; recti=straight

2 oblique; oblique= curved

25
Q

The eye muscles are slightly ______ in orientation.

The _______ muscles are needed to overcome angles

A

medial

oblique

26
Q

All eye muscles originate from the ______ _______, except the _______ _______.

A

Annular ring

Inferior oblique

27
Q

The inferior oblique muscle begins from where?

A

The medial orbit surface

28
Q

Superior oblique goes through the ______ before inserting on the eyeball

A

trochlea

29
Q

What is the trochlea?

A

A fibrocartilaginous loop on medial orbit, the superior oblique muscle travels through it.

30
Q

What is special about the motor units of the eye?

A

Fine movements of eyes to see tiny bits of detail (1 axon: 8 muscle fibers), vs 1:2000 in some skeletal muscle.

31
Q

Why does the eye need oblique muscles?

A

The superior and inferior recti cannot elevate or depress the eye without also turning it medially because they approach the eye from a posteromedial direction. For an eye to be directly elevated or depressed, the lateral pull of the oblique muscles is necessary to cancel the medial pull of the superior and inferior recti muscles

32
Q

What muscle raises the upper eyelid?

A

Levator palpebrae superioris