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Ocular Block 8 > Ocular Development > Flashcards

Ocular Development Flashcards

1
Q

What kinds of things are typically derivatives of surface ectoderm

A

Surface of body and things that continually change/grow/ proliferate throughout life

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2
Q

What are the layers of the optic cup

A
  • inner layer
  • outer layer
  • optic fissure
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3
Q

What goes through the optic fissure

A

Hyaloid artery

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4
Q

What happens if the optic fissure does not close before birth

A

Coloboma

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5
Q

The nerve fibers that emerge from the retinal ganglion cells in the 6th week travel along

A

The inner wall of the optic stalk to reach the brain

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6
Q

What happens to the optic stalk in the eighth week

A

The lumen of the stalk is gradually obliterated by growth of the the retinal ganglion cells that travel along the inner wall of the optic stalk, and by the eight week, the hollow stalk is transformed into the solid optic canal

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7
Q

What are the two sources of vasculariszation of the eye in development

A
  1. Choroid layer around the eye

2. Transient hyaloid artery

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8
Q

Where does the hyaloid artery come from

A

Ophthalmic artery

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9
Q

How does the hyaloid artery gain access to the lentiretinal space

A

Via the optic fissure on the ventral surface of the optic stalk

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10
Q

What does the hyaloid artery supply

A

Developing retina and initially the lens

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11
Q

Branches of the hyaloid artery extend over the lens and are known as the

A

Tunica vasculosa lentis

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12
Q

When do the lips of the optic fissure fuse

A

By day 37

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13
Q

What happens when the optic fissure closes

A

Encloses the hyaloid artery and its accompanying vein in TCA canal within the ventral wall of the optic stalk

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14
Q

When is the hyaloid vasculature maximally developed

A

10 weeks

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15
Q

Lens maturation and hyaloid artery supply

A

When the lens materus during fetal life and ceases to need a blood supply, the portion of the hyaloid artery that crosses the vitreous body degenerates and is removed by macrophages

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16
Q

What is the hyaloid artery degenerated by

A

Macrophages

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17
Q

As an adult, the course of the hyaloid artery is marked by a conduit through the vitreous body called the

A

Hyaloid canal (cloquets canal)

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18
Q

What does the proximal portion of the hyaloid artery become

A

CRA

19
Q

Vascularization of the retina as the hyaloid artery

A

Is regressing and is predominant during the final trimester

20
Q

What happens when a premie is born with their retinas

A

The vasculature has not developed yet, so they get retinopathy. Need to be put on oxygen to allow the vessels to mature properly

21
Q

When does the mesenchymal capsule that surrounds the optic cup differentiate into 2 layers?

A

Week 6 and 7

22
Q

What are the two layers that the mesenchymal capsule that surrounds the optic cup differentiate into

A
  1. Inner pigmented vascular layer called the choroid

2. Outer, fibrous layer called the sclera

23
Q

What is the choroid layer homologous to

A

Pia mater and arachnoid membranes

24
Q

What is the scler homologous to

A

Dura mater

25
Q

What does the choroid develop from

A

Neural crest cell-derived mesenchyme and mesoderm

26
Q

The anterior sclera begins as a condensation of __________

A

Mesenchymal tissue that is continuous with the cornea

27
Q

What are the 3 tissue origins of the cornea

A
  1. Head mesoderm: endothelium
  2. Neural crest cells: stroma
  3. Surface ectoderm: outer corneal epithelium
28
Q

Mesenchyme overlying the lens

A

Splits into two layers that enclose a new cavity called the anterior chamber of the eye

29
Q

What is the anterior wall of the anterior chamber continuous with

A

Sclera

30
Q

What is the posterior wall of the anterior chamber continuous with

A

Choroid

31
Q

This thin remaining layer, called the __________, regresses early in fetal period (between 6-8 months) to form the opening called the pupil

A

Pupillary membrane

32
Q

What happens when the pupillary membrane does not break down

A

Leaves strands that traverse the pupil. The posterior chamber eventually underlies the iris and part of the ciliary body

33
Q

What does the iris stroma develop from

A

Mesenchymal tissue of both neural crest and mesodermal origin

34
Q

The posterior iris epithelium and the circumferential arranged smooth muscle bundles of the pupillary muscles in the iris originate from

A

The neuroepithelium of the optic cup

35
Q

Inner layer of the optic cup becomes what portion of the iris

A

Posteiror border of the iris

36
Q

Just posterior to the developing iris, the optic cup diffentiates and folds to form the

A

Ciliary body

37
Q

Mesenchymal cells that invade the choroid of the ciliary body differentiate to form the _____________, which controls the shape and hence the focusing power of the lens

A

Smooth muscle bundles of the ciliary muscle

38
Q

What are eyelids derived from

A

Surface ectoderm

39
Q

What is the space between the fused eyelids and the cornea called

A

Conjunctival sac

40
Q

When do the eyelids separate

A

5-7 months

41
Q

What are the eyelid muscles derived from

A

Mesoderm

42
Q

What are the lacrimal glands derived from

A

Surface ectoderm

43
Q

When does the lacrimal gland mature

A

6 weeks after birth

44
Q

Mittendorfs dot

A

Never goes away. Remnants of the hyaloid artery stuck to the back of the lens

Ocular Block 8 (6 decks)

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