Embryology — Flashcards

Flashcard 351: In which week of embryogenesis do genitalia begin to develop male/female characteristics? _____

Answer: Week 10 ("Tenitalia")

Flashcard 352: What is the embryonic origin of dura mater? _____

Answer: Mesoderm

Flashcard 353: The ganglion cells that fail to descend in Hirschsprung disease are derived from _____

Answer: neural crest

Flashcard 354: The neural tube begins as _____ (number) primary vesicles

Answer: three

Flashcard 355: What is the embryonic origin of parafollicular cells (C cells) of the thyroid?

Answer: Neural crest cells

Extra: Parafollicular cells (C cells) are derived from **neural crest cells** (migrating into the ultimopharyngeal body, which is derived from the 4th pharyngeal pouch). In contrast, the **follicular cells** of the thyroid gland are derived from **endoderm** (the thyroid diverticulum from the floor of the pharynx).

Flashcard 356: Which branchial arch gives rise to all intrinsic muscles of the larynx, except the cricothyroid? _____

Answer: 6th arch

Flashcard 357: In which period of lung development do pneumocytes develop? _____

Answer: Canalicular period (weeks 16–25)

Flashcard 358: The adrenal medulla is of _____ origin

Answer: neural crest

Flashcard 359: Breast tissue can develop anywhere along the _____, which runs from the axilla to the vulva (e.g. supernumerary nipples)

Answer: milk line

Flashcard 360: _____ chromosomes are characterized by very short p arms

Answer: Acrocentric