**Question:** Optic vesicle is derived from -

A. Ectoderm
B. Mesoderm
C. Hypoblast
D. Yolk sac

**Core Concept:** The optic vesicle is a developmental structure that plays a crucial role in the formation of the eye during embryonic development. It is part of the process known as neurogenesis, which is the formation of neurons in the central nervous system.

**Why the Correct Answer is Right:** The optic vesicle is derived from the ectoderm, which is one of the three germ layers in the early embryo. It is formed during the process of neurulation, where ectoderm cells migrate and fold to create the neural plate and eventually the neural tube. In the context of the eye, the optic vesicle develops into the optic cup, which gives rise to the neural retina and other eye structures.

**Why Each Wrong Option is Incorrect:**

A. Mesoderm: The optic vesicle is not derived from mesoderm, which is responsible for forming the skeletal muscles, blood vessels, and connective tissues.

B. Hypoblast: Hypoblast is the inner cell mass of the embryo, not involved in the development of the optic vesicle.

D. Yolk sac: The yolk sac is an extraembryonic structure that stores nutrients for the developing embryo, not involved in the formation of the optic vesicle.

**Clinical Pearl:** Understanding the origin of the optic vesicle from ectoderm is essential for understanding eye development and any potential anomalies or diseases related to the eye. A proper understanding of embryonic development can assist in diagnosing and treating conditions like anophthalmia, microphthalmia, and coloboma, which are developmental abnormalities involving the eye.