MFAC1522 Lecture Notes - Lecture 1: Pharyngeal Arch, Neurogenic Placodes, Neural Crest
24 Jun 2019
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Document Summary
Describe the relevant events in week 4 (1) breakdown of the buccopharyngeal (oral) membrane: which opens the git and. Describe the general contributions of the pharyngeal arches. The human has 5 different pharyngeal arches: pharyngeal arches 1, 2, 3, 4, and. 6, developed in a rostrocausal fashion (also decreases in size). Note that pharyngeal arch 5 does not form or regresses rapidly. Gives rise to the face, tongue, lip, jaw, palate, pharynx, cranial nerves in the neck, sense organ compartments and glands; face structures are mainly by arch 1 and. Arch 1 - elongates to form tubotympanic recess (which eventually forms the tympanic cavity, mastoid antrum and eustachian tube) Arch 2 - forms tonsillar sinus, mostly oblierated by palatine tonsil. Arch 3 - forms inferior parathyroid and thymus. Arch 4 - forms superior parathyroid, parafollicular cells of thyroid (c cells which secrete calcitonin, important for regulating plasma calcium levels) Arch 1 - mainly lost, but form part of maxillary artery.
