Embryology and Development — Flashcards

Flashcard 241: The lens fibers are produced by mitosis of the epithelial cells in the _____ zone.

Answer: pre-equatorial

Flashcard 242: What are the skeletal derivatives of the sixth arch?_____

Answer: Arytenoid cartilage

Flashcard 243: What are the muscular derivatives of the second arch?_____

Answer: Stapedius, Stylohyoid, Facial Muscles (Buccinator, Platysma, Posterior belly of digastric) (5)

Flashcard 244: The choroidal vessels are formed from the _____derm

Answer: meso

Flashcard 245: The crystalline lens is derived from which embryologic layer?

Answer: Surface ectoderm

Flashcard 246: The optic groove appears by _____ weeks

Answer: 4 (Day 22)

Extra: The optic groove (optic sulcus) appears at approximately **day 22** of development, which is the beginning of the **4th week**. It is the first morphological sign of eye development, appearing in the neural folds of the future forebrain (prosencephalon).

Flashcard 247: Cervix:corpus ratio before puberty is _____

Answer: 2:1

Flashcard 248: Which chorionic villi contain an outer layer of syncytiotrophoblast, an intermediate core of cytotrophoblast and an inner core of EEM with fetal capillaries?_____

Answer: Tertiary

Flashcard 249: The primary ossification center of the tibia appears at _____ week of intra-uterine life.

Answer: 7th

Flashcard 250: The cochlea is developed sufficiently by _____ weeks of gestation

Answer: 20