It was prepared for the purpose of stimulating group discussion in a conference setting. No warranties, either express or implied, are made with respect to its accuracy, completeness, or timeliness. The material does not necessarily reflect the current or past opinions of members of the UTMB faculty and should not be used for purposes of diagnosis or treatment without consulting appropriate literature sources and informed professional opinion. B. basically a gill slit type of development at this time with 5 pairs of mesodermal arches separated by 4 pairs of grooves or clefts externally and pouches internally. D. pouches develop into entoderm derivatives.
E. grooves develop into ectoderm derivatives.
F. pouches become glandular structures and in the process their connection to the ectoderm of the groove obliterates and remnants of this connection become branchial sinuses and cysts. G. each arch is associated with an artery, nerve, and cartilage bar. and muscle component. The nerves are anterior to the arteries except in the fifth arch, where it is posterior. Caudal to all arches is the XIIth nerve. The sternocleidomastoid muscle is derived from cervical somites posterior and inferior to the above arches.