Eye Development Quiz

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Questions and Answers

What embryonic layer is responsible for forming the retina, iris, and optic nerve?

Mesoderm

Surface ectoderm

Neuroectoderm (correct)

Outer ectoderm

At what stage does the optic vesicle form from the optic sulci?

Day 22 (correct)

Week 7

Day 18

Week 5

What structure does the optic vesicle become when it invaginates?

Optic stalk

Optic cup (correct)

Choroid fissure

Lens vesicle

What is the name of the structure formed at the mouth of the optic cup?

Future pupil Signup and view all the answers

Which embryonic layer contributes to the formation of the lens?

Surface ectoderm Signup and view all the answers

What is the role of the choroid fissure during eye development?

To permit the hyaloid artery to reach the inner chamber Signup and view all the answers

What happens during week 7 of eye development?

The choroid fissure closes Signup and view all the answers

Which structure connects the optic vesicle to the prosencephalon?

Optic stalk Signup and view all the answers

What forms the outer layer of the cornea?

Surface ectoderm Signup and view all the answers

Which congenital defect results from the failure of the choroid fissure to close?

Coloboma iridis Signup and view all the answers

Why is the cornea considered avascular?

It has no blood vessels. Signup and view all the answers

What is the primary cause of congenital cataracts during intrauterine life?

Rubella infection Signup and view all the answers

What separates the anterior and posterior chambers of the eye?

Iris Signup and view all the answers

How does the cornea maintain its transparency?

Through constant removal of water Signup and view all the answers

What layer of the eye covers the posterior 5/6ths and is primarily made of collagen?

Sclera Signup and view all the answers

At approximately what week do the eyelids open during prenatal development?

Week 26 Signup and view all the answers

What happens to the iridopupillary membrane during development?

It generally obliterates to allow communication between chambers. Signup and view all the answers

Which statement best describes the substantia propria of the cornea?

It is an avascular region. Signup and view all the answers

What is the function of the outer layer of the optic cup in the retina?

It acts as a simple, cuboidal, pigmented epithelium. Signup and view all the answers

What occurs if there is a separation of the inner and outer layers of the retina?

Retinal detachment may occur. Signup and view all the answers

From which embryonic origin are the ciliary body muscle and connective tissue derived?

Mesenchyme adjacent to the optic cup Signup and view all the answers

What structure is formed from the optic stalk?

Optic nerve Signup and view all the answers

Which statement best describes the anterior 1/5 of the inner layer of the optic cup?

It is pigment-free and non-photoreceptive. Signup and view all the answers

What is the fate of the hyaloid vessels as the optic stalk develops?

They become the central retinal artery and vein. Signup and view all the answers

What process occurs at approximately the 10th week postnatally concerning the optic nerve?

It undergoes complete myelination. Signup and view all the answers

What embryonic structure ultimately gives rise to the sclera of the eye?

Mesenchyme surrounding the optic cup Signup and view all the answers

What primary role does the retinal pigment epithelium play in the posterior retina?

It absorbs excess light and prevents scattering. Signup and view all the answers

What is the significance of the intraretinal space between the two layers of the retina?

It contains a small amount of fluid. Signup and view all the answers

What is the primary function of rods in the retina?

Night vision under low light conditions Signup and view all the answers

Which type of photoreceptor has the highest convergence with bipolar cells?

Rods Signup and view all the answers

What role do horizontal and amacrine cells play in the retina?

They enhance visual data for contrast. Signup and view all the answers

Which statement about cones is correct?

They are specialized for visual acuity. Signup and view all the answers

What substance is regenerated in rods under low illumination?

Visual pigment Signup and view all the answers

What is the role of zonular fibers in relation to the lens?

They maintain the ellipsoidal shape of the lens. Signup and view all the answers

At what age does the lens begin to lose its elasticity?

40 Signup and view all the answers

What is a cataract?

A clouded or opaque lens. Signup and view all the answers

What is the function of the sphincter pupillae muscle?

To constrict the pupil. Signup and view all the answers

What structure contains the ciliary muscle for lens accommodation?

Ciliary body Signup and view all the answers

What part of the retina is not photoreceptive?

Anterior portion Signup and view all the answers

What muscle enlarges the pupil?

Dilator pupillae Signup and view all the answers

What structure is responsible for providing blood supply to the retina?

Choriocapillaris Signup and view all the answers

Which of the following statements about the lens is true?

The lens's thickness is regulated by the ciliary body. Signup and view all the answers

Which cell type is found in the neural retina?

Retinal pigment epithelium Signup and view all the answers

Study Notes

Eye Development

The eye develops from three embryonic layers: neuroectoderm, surface ectoderm, and mesoderm.
On day 22, optic vesicles appear on the forebrain, later forming the optic cup and lens vesicle.
The optic vesicle contacts the surface ectoderm, inducing the formation of the lens placode.
The lens placode invaginates and detaches from the surface ectoderm, forming the lens vesicle.
The optic vesicle invaginates to form the double-layered optic cup.
The choroid fissure allows the hyaloid artery to reach the inner chamber of the eye.
The choroid fissure closes in week 7, forming the future pupil.
The optic stalk connects the optic vesicle to the prosencephalon and becomes the optic nerve.

Derivatives of the Optic Cup

The retina is formed by two layers: outer pigmented epithelium and inner photoreceptive layer.
The ciliary body is covered by epithelial layers from the optic cup and connective tissue from mesenchyme.
The iris is covered by epithelial layers from the optic cup and contains neuroectodermal smooth muscle fibers.
The optic nerve derives from the optic stalk and contains the central retinal artery and vein.

Other Eye Structures

The choroid and sclera are formed from mesenchyme surrounding the optic cup.
The cornea is transparent and avascular, while the sclera is opaque and vascular.
The anterior chamber forms in mesenchyme between the lens vesicle and surface ectoderm.
The iridopupillary membrane disappears, allowing communication between the anterior and posterior chambers.
The cornea develops from surface ectoderm and mesenchyme.

Congenital Defects

Coloboma iridis occurs when the choroid fissure fails to close.
Persistent iridopupillary membrane is caused by incomplete resorption of the iridopupillary membrane.
Congenital cataracts are caused by a lens becoming opaque during intrauterine development, sometimes due to rubella infection.

Eye Histology

The cornea is the outermost connective tissue layer containing pain receptors and responsible for light transmission.
The sclera covers the posterior 5/6ths of the eye and contains collagen and elastic fibers.
The lens is a biconvex structure suspended by zonular fibers and responsible for focusing light.
The uvea is the vascular middle layer of the eye.
The choroid contains a network of capillaries.
The ciliary body contains the ciliary muscle responsible for lens accommodation.
The iris regulates light entering the eye by adjusting the pupil size.
The sphincter pupillae constricts the pupil (miosis), while the dilator pupillae dilates it (mydriasis).
The retina is a thin tissue lining the posterior wall of the eye, composed of seven cell types.

Retina Cell Types

The retinal pigment epithelium (RPE) absorbs excess light, stores vitamin A, supports photoreceptors, and phagocytizes shed photoreceptor segments.
Photoreceptors (rods and cones) are light-sensitive neurons responsible for vision.
Rods are sensitive to low light and responsible for night vision.
Cones provide color vision and high acuity.
Bipolar cells connect photoreceptors to ganglion cells.
Horizontal and Amacrine cells modify visual data to enhance borders and contrast.
Muller cells provide metabolic support to retinal cells, similar to oligodendrocytes.

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Description

Test your knowledge on the fascinating process of eye development. This quiz covers the embryonic layers involved, the formation of the optic vesicle, and the derivatives of the optic cup. Challenge yourself and learn more about how the eye structure evolves from an early stage.