W6_01 Eye: Anatomy and Physiology Flashcards

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1
Q

what divides the eye into the anterior and posterior segments?

A

the lens

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2
Q

what separates the anterior and posterior chambers?

A

the iris

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3
Q

name structures in the anterior segment of the eye

A
sclera
cornea
anterior chamber
iris
ciliary body
lens
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4
Q

name the perforation in the sclera to allow optic nerve penetration

A

lamina cribosa; meshwork that allows passage of CN II fibres

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5
Q

3 components of the conjunctiva

A

palpebral
forniceal
bulbar

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6
Q

describe episclera vasculature

A

2 layers: superficial and deep.

deep vessels are larger

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7
Q

name two pathologies of the episclera

A

episcleritis

scleritis (serious; due to rheumatoid arthritis)

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8
Q

what’s the division of diopter power in the eye?

A

cornea: 2/3 (~40D)
lens: 1/3 (~20)

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9
Q

3 reasons for transparency within the cornea?

A

avascularity
uniform structure
deturgescence

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10
Q

thickness of cornea?

A

centrally 0.54mm;

peripherally 1 mm

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11
Q

how many layers of the cornea?

A

5

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12
Q

what are the layers of the cornea?

A
epithelium
Bowman's membrane
stroma
Descemet's (basement) membrane
endothelium
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13
Q

difference between cornea and sclera?

A

collagen is coarse and irregular in sclera, causing opacity

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14
Q

components of the lens?

A

capsule
epithelium
nucleus
cortex

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15
Q

types of cataracts?

A
cortical
nuclear sclerosis (aging)
posterior subcapsular (steriods, diabetes)
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16
Q

where can intraocular lenses be implanted?

A

anterior chamber

posterior chamber

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17
Q

components of the uvea?

A

iris (anterior)
ciliary body (middle)
choroid (posterior)

18
Q

muscles in the iris?

A

sphincter muscle constricts (cholinergic)

dilator muscle dilates (adrenergic)

19
Q

function of the pars plicata?

A

producing aqueous humour for the anterior chamber

20
Q

functions of the ciliary body?

A

production of aqueous humour

accomodation

21
Q

how is aqueous humour drained?

A

trabecular meshwork to canal of schlem

uveascleral outflow to episcleral venous vessels

22
Q

what attaches the lens to the ciliary body?

A

zonules

23
Q

how do the lens, ciliary bodies, and zonules change in shape to accommodation?

A

ciliary body SM contracts; CB moves anteriorly
zonules relax
lens rounds up

24
Q

components of the posterior segment?

A

vitreous
retina
choroid
optic nerve

25
Q

vitreous pathology?

A
vitreous homorrhage (e.g. diabetics)
fungus endophthalmitis
26
Q

how big is the optic disc?

A

1.5mm in diameter

27
Q

what is the macula?

A

centre of retina;
fovea is centre of macula;
most detailed vision from here

28
Q

how many layers in the retina?

how many layers does light penetrate to get to rods/cones?

A
  1. light goes through 8 layers to reach rods/cones.
29
Q

choroidal pathology?

A

choroidal nevus

choroiditis

30
Q

describe the optic nerve pathway and lengths

A

intraocular (1 mm)
intraorbital (25mm)
intracannalicular (9 mm)
intracranial (16 mm)

31
Q

optic nerve pathology?

A

optic disc edema

glaucoma

32
Q

7 bones that make up the orbit?

A
frontal
sphenoid
zygomatic
maxillary bone
lacrimal bone
ethmoid bone
palatine
33
Q

what passes through the optic foramen? the optic foramen is in which bone?

A

optic nerve and opthalmic artery;

in sphenoid bone

34
Q

what passes through the superior orbital fissure? the fissure is made from which bone?

A

CN III, IV, V1, VI, superior opthalmic vein, vessels;

fissure is between greater and lesser wings of sphenoid

35
Q

layers of the tear film?

A

lipid layer
aqueous layer
mucin layer
corneal epithelium

36
Q

what produces the mucin layer of the tear film?

A

conjunctival goblet cells

37
Q

what produces the aqueous layer of the tear film?

A

accessory lacrimal glands (kraus and wolfring)

38
Q

what produces the lipid layer of the tear film?

A

meibomian gland in lid margin

39
Q

tear pathologies?

A

dry eye (loss of either layer)
blurry vision
can be caused by blepharitis

40
Q

lacrimal gland pathology?

A

congenital lasolacrimal duct obstruction

dacryocystitis