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Human Anatomy > Lecture 19 Content > Flashcards

Lecture 19 Content Flashcards

1
Q

What makes up the Fibrous Tunic of the eye?

A
  1. Sclera

2. Cornea

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2
Q

describe the sclera?

A

Dense CT “white of the eye”

  • attachment site for extrinsic eye muscles
  • elastic/mechanical support for globe
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3
Q

Describe the cornea?

A
  • modified sclera (1/6th of globe)
  • avascular, several nerve endings
  • transparent bulge @ anterior suface
  • bulge refracts light before it hits lens
  • all nutrients from air
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4
Q

What makes up the Vascular Tunic?

A
  1. Choroid
  2. ciliary body
  3. Iris
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5
Q

Describe the Choroid layer?

A

inner surface of globe (posterior)

  • vascular = helps nourish retina
  • black pigmentation absorbs stray light
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6
Q

Describe the cilary body?

A

composed of muscles and ligaments

  • smooth muscles - radial and circular (sphinter-like) fibers
  • suspensory “ligaments” of lens
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7
Q

Describe the Iris?

A

colored portion of the eye

  • smooth muscles - radial and circular (sphincter like) fibers
  • muscle contractions controls diameter of pupil (hole)
  • separates the anterior cavity into ant/post chambers
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8
Q

What makes up the anterior cavity?

A

has 2 chambers anterior to the lens

  1. anterior chamber - anterior to the iris
  2. posterior chamber - posterior to the iris
  3. aqueous humor
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9
Q

describe the Aqueous humor?

A

fills anterior cavity

  • produced by the ciliary process
  • returned to blood supply via the canal of Schlemm
  • helps control intra occulor pressure
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10
Q

What makes up the posterior cavity?

A

posterior to lens (aka vitreous chamber)

  • lens to retina
  • vitreous humor (gel-like) fills posterior cavity
  • assist sclera in maintaining shape of eyeball
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11
Q

What is the suspensory ligaments?

A

barrier between ant/post. cavity

  • composed of 3 membrane (fused)
  • lens is sandwiched between between layers
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12
Q

What is Glucoma?

A

several different types

  • circulation of aqueous humor is blocked
  • increased pressure > damage to the optic nerve
  • edema in cornea > cloudy/grey-green eye
  • offten assoc. w/ high blood pressure (+/- family history
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13
Q

The neural tunic is composed of what?

A

RETINA

  • posterior pigmented layer
  • anterior pigmented layer
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14
Q

What does the Posterior pigmented layer of the Neural tunic do?

A
  • dark pigment absorbs stray light

- supports anterior neural layer

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15
Q

What does the anterior “neural” layer do in the neural tunic?

A

Anterior Neural layer contains 9 layers

  • neurons, neuroglia, and blood vessels
  • ganglia = integration and preliminary processing
  • 130 million photoreceptors in a circular sheet
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16
Q

What are the 2 photoreceptors in the eye?

A

Rods : dim light (light/dark) 125 million per eye

Cones: 6 million per eye - most in the fovea centralis

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17
Q

Describe cones in the eye?

A
  • requires “high energy” - bright light
  • cone receptors turned to specific wave-lengths
  • absense of any one type of cone = color blindness
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18
Q

What does the Macula Lutea and the fovea centralis do?

A
  • center of visual axis
  • contains high concentration of cones
  • spot of greatest resolution (sharpest focus)
19
Q

What is the blind spot?

A

Point where point where optic nerve exits the globe

  • point where blood vessels enter/exit the globe
  • located very close to and just medial to the fovea
19
Q

What is the blind spot?

A

Point where point where optic nerve exits the globe

  • point where blood vessels enter/exit the globe
  • located very close to and just medial to the fovea
20
Q

Describe the globe of the eye and the retina?

A

formed as lateral diverticula of the diencephalon

  • each diverticulum collapses to form eye cup
  • retina this early in neural tube arrangement**
  • retina subsequently appears to be installed backwards
20
Q

Describe the globe of the eye and the retina?

A

formed as lateral diverticula of the diencephalon

  • each diverticulum collapses to form eye cup
  • retina this early in neural tube arrangement**
  • retina subsequently appears to be installed backwards
21
Q

What are some of the clinical implications/ mechanical limitations of the eye?

A

light receptors (rods and cones) pointing the wrong way
receptors buried behind 9 layers
Blind spot where axons and blood vessels leave globe’
Result of 70 % of the image is lost
ONLY SEE 30%

22
Q

describe the pineal gland?

A

tied to light reception diurnal behavior patterns

- out-pocketing of the diencephalon

23
Q

Describe the Iris and what CN is it associated with?

A

CN III
- complicated circular and radial muscles (antagonist)
- sympathetic simulation > dilation of pupil
- parpsympathetic simulation > contraction of pupil
= regulates the amount of light that asses to retina

24
Q

describe the ciliary muscles? and what CN is it associated with?

A
  • complicated internal ring of muscles
  • contraction REDUCES tension of the suspensory ligament
  • suspensory “ligaments” affect how the lens stretched
  • shape of lens affects where the eye focuses
  • CILIARY MUSCLES DO NOT PULL UPON SUSPENSORY LIG.
25
Q

Describe the Lens?

A
  • thick biconvex disc of specialized fibers
  • orientation of fibers makes the lens transparent
  • no Blood vessels
  • suspended from sclera by suspensory ligaments
26
Q

what is accommodation? and what does it do? close and far objects?

A

ability to focus
- requires change in lens shape - little or lens movement
close objects?
- ciliary muscles contract, slack on suspensory ligaments and lens BULDGE
Far objects?
- ciliary muscles relax, ligaments tighten and lens FLATTENS

27
Q

what is presbyopia?

A
  • lens becomes stiff with old age
  • ability to change shape of lens slows
  • refractive property of lens also change
  • can’t focus on near objects = (far-sighted)
  • lens is ridged
28
Q

What are cataracts?

A

(abnormal lens)

  • combo of structural/bio-mechanical problems
  • lens becomes cloudy (less light passes to retina)
  • focusing becomes “patchy” across retina
29
Q

What does the levator palpebrae superioris do? and CN associated with it?

A

Lift upper eyelid (CN III)

30
Q

What does the obicularis oculi do and CN associated with it?

A

closes both eye lids (CN VII)

31
Q

What does lateral rectus do and what CN is associated with it?

A

lateral movement - abducens CN VI

32
Q

What does medial rectus do and what CN is associated with it?

A

medial movement - oculomotor CN III

33
Q

What does superior rectus do and what CN is associated with it?

A

superior movement - oculomotor CN III

34
Q

What does inferior rectus do and what CN is associated with it?

A

Inferior movement - occulomotor - CNIII

35
Q

What does Superior oblique do and what CN is associated with it?

A

inferior and abduction (laterally)

- Trochlear CN IV

36
Q

What does inferior oblique do and what CN is associated with it?

A

superior and abduction (laterally)

- oculomotor (CN III)

37
Q

What does the palpebrae do?

A

upper and lower eyelids

38
Q

What does the Canthi do?

A

medial and lateral canthus (w/ caruncle)

39
Q

What is the conjunctiva?

A 
single layer (skin ) that covers anterior surface of eye 
- conjunctivitis = pink eye conjunctival inflammations
40
Q

What is the lacrimal gland?

A

superolateral corner of orbit

  • secretes teas that bathe conjunctiva and cornea
  • wash, moisten, minimize friction
41
Q

What is the lacrimal apparatus?

A
  • tears are squeezed into medial canthus with each eye blink
  • tears drain through (lacrimal puncta) into canaliculi
  • lacrimal sac > nasolarimal duct > nasal cavity
42
Q

what is the Trochlea used for?

A

sling of CT for superior oblique muscle

Human Anatomy (14 decks)

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