Chapter 16 Eye and Ear

Chapter 16  Eye and Ear

Complete Chapter Questions And Answers
 

Sample Questions

7. ________ Tunica vasculosa lentis
a.
Scleral venous sinus
b.
Optic nerve
c.
Corneal epithelium
d.
Central artery of retina
e.
Pupillary membrane

ANS: E
The anterior part of the tunica vasculosa lentis, a vascular layer around the embryonic lens, is called the pupillary membrane. When the distal part of the hyaloid artery degenerates, the tunica vasculosa lentis, including the pupillary membrane, also degenerates. Remnants of this membrane often appear as tissue strands in normal eyes of infants, but these strands usually cause little disturbance of vision and tend to disappear in old age.

8. ________ Ganglion cells of retina
a.
Scleral venous sinus
b.
Optic nerve
c.
Corneal epithelium
d.
Central artery of retina
e.
Pupillary membrane

ANS: B
As the neural layer of the retina develops from the inner layer of the optic cup, the axons of ganglion cells in the retina pass into the inner wall of the optic stalk and gradually convert it into the optic nerve.

9. ________ Hyaloid artery
a.
Scleral venous sinus
b.
Optic nerve
c.
Corneal epithelium
d.
Central artery of retina
e.
Pupillary membrane

ANS: D
The hyaloid artery passes along the retinal fissure to the optic cup, where it supplies blood to the developing neural layer of the retina and to the embryonic lens. The distal portion of this artery usually degenerates, but the proximal part persists as the central artery of the retina. Persistence of the distal part of the hyaloid artery is a fairly common abnormality. It may persist in whole or in part, but it usually is not patent. The hyaloid arterial remnant appears as a thin line or thick cord in the vitreous humor.

10. ________ Surface ectoderm
a.
Scleral venous sinus
b.
Optic nerve
c.
Corneal epithelium
d.
Central artery of retina
e.
Pupillary membrane

ANS: C
The corneal epithelium is derived from the surface ectoderm. The lens functions as an inductor and influences the surface ectoderm to develop into the epithelium of the cornea. The substantia propria of the cornea is derived from mesenchyme.