Embryology — Flashcards

Flashcard 411: What is the embryonic origin of the posterior pituitary?_____

Answer: neuroectoderm

Flashcard 412: Deoxygenated blood is returned to the placenta via the _____

Answer: umbilical arteries

Flashcard 413: Which branchial pouch (wings) gives rise to the inferior parathyroids?_____

Answer: 3rd pouch (dorsal wings)

Flashcard 414: The thyroid develops at the base of the tongue (primitive pharynx) and then travels along the _____ duct to the anterior neck Bonus: forms from which arch?

Answer: thyroglossal Bonus: 1st and 2nd pharyngeal arches (floor of the primitive pharynx)

Flashcard 415: Which gene(s) are produced at the **apical ectodermal ridge** (AER) to regulate the **proximo-distal** axis of limb development?

Answer: FGF (Fibroblast Growth Factor) genes

Extra: Major signaling centers in limb development: - **AER** (Apical Ectodermal Ridge): Secretes **FGF** (stimulates proximo-distal outgrowth). - **Dorsal ectoderm**: Produces **Wnt-7a** (regulates dorsal-ventral axis). - **ZPA** (Zone of Polarizing Activity): Produces **Shh** (regulates antero-posterior axis). - **Hox genes**: Regulate segmental organization (location) of limbs.

Flashcard 416: During which week of gestation does gastrulation occur?_____

Answer: 3

Flashcard 417: What congenital abnormality arises due to hyperplasia of the frontonasal prominence?_____

Answer: Orbital hypertelorism

Flashcard 418: The mesonephros later contributes to the _____ genital system

Answer: male

Flashcard 419: What is the adult derivative of the wall of the telencephalon? _____

Answer: Cerebral hemispheres

Flashcard 420: During which week of gestation is the bilaminar disc (of epiblast and hypoblast) formed?_____

Answer: Week 2