Special Senses: the visual system Flashcards Preview

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Flashcards in Special Senses: the visual system Deck (35):
1

• Lacrimal apparatus

o Lacrimal gland, lacrimal canaliculi, lacrimal sac, and nasolacrimal duct

2

• Lacrimal glands

o Situated superior to the lateral aspect of the eye
o Release a dilute salt solution (tears)

3

• Lacrimal puncta

o an opening through which fluid enters each lacrimal canaliculum.

4

• Lacrimal canaliculi

o form the first part of the nasolacrimal drainage apparatus that drains tears produced by the lacrimal gland.

5

• Nasolacrimal duct

o carries tears from the lacrimal sac into the nasal cavity.

6

• Lysozyme

o Antibacterial enzyme
o Contained in lacrimal secretion

7

• Eyelids/palpebrae

o Protect the anterior surface of each eye

8

• medial commissure (canthus)/lateral commissure (canthus)

o form the lateral and medial corners of the eyes.

9

• lateral caruncle

o fleshy raised area at the medial commissure
o produces whitish oily secretion

10

• conjunctiva

o mucous membrane
o lines the internal surface of the eyelids and continues over the anterior surface of the eyeball to its junction with the corneal epithelium

11

• ciliary glands

o modified sweat glands
o lie between the eyelash hair follicles and help lubricate the eyeball

12

• tarsal glands


o are a special kind of sebaceous gland at the rim of the eyelids inside the tarsal plate

13

• extrinsic eye muscles

o attached to the exterior surface of each eyeball
o control eye movement and make it possible for the eye to follow a moving object
o lateral rectus, medial rectus, superior rectus, inferior rectus, inferior oblique, superior oblique

14

• fibrous layer


o protective layer composed of dense avascular connective tissue

15

• cornea

o where light enters the eye

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• vascular layer

o called uvea
o middle layer of internal eye

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• choroid

o blood rich nutritive region containing a dark pigment that prevents light scattering within the eye

18

• ciliary muscles

o smooth muscles important in controlling lens shaoe and ciliary processes

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• pupil

o a rounded open which lets light pass

20

• intrinsic muscles of the eye

o spincter pupillae of iris
o dilator pupillae of iris
o ciliary muscles

21

• retina


o innermost sensory layer of the eye
o three layer: photoreceptors, bipolar cells, and ganglion cells

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• pigmented layer

o abuts the choroid and extends anteriorly to cover the ciliary body and the posterior side of the iris

23

• neural layer


o extends anteriorly only to the ciliary body
o contains the photoreceptors (cones and rods)

24

• optic disc/blind spot

o where the optic nerve leaves the eyeball
o located in a weak spot in the fundus(posterior wall)

25

• macula lutea/yellow spot

o an area of high cone density

26

• fovea centralis

o a tiny pit about 0.4 mm in diameter
o contains only cones and is in the area of greatest visual acuity

27

• lens

o a flexible crystalline structure held vertically the in eyes interior by the ciliary zonule attached to the ciliary body

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• ciliary zonule

o suspensory ligament

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• scleral venous sinus

o reabsorbs aqueous humor

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• optic nerve


o bundle of fibers where axons of the ganglion cells leave the retina

31

• sclera

o White of the eye
o Forms bulk of the fibrous layer

32

• conjunctivitis

o inflammation of the conjunctiva often accompanied by redness of the eye

33

• sty

o an inflammation of one of the ciliary glands or small oil gland

34

• cataracts

o cause vision to become hazy or entirely obstructed

35

• glaucoma

o when intraocular pressure reaches dangerously high levels the retina and optic nerve are compressed resulting in pain and possible blindness