Dears,
in Kaplan's home study program it is mentioned that there is a 5th phayrngeal pouch that forms the ultimobranchial bodies which give rise to calcitonin secreting parafollicular (C) cells of the thyroid.
but in High Yield embryology... it is mentioned that the 5th pharyngeal pouch completely regresses in human and that the ultimobranchial bodies come from the ventral wing of the 4th pharyngeal pouch (which is against what is written in kaplan)... which one is correct???
second thing... whether the parafollicular cells (which are rised from ultimobranchial bodies of endodermal orgin) are originated from the 4th or 5th pharyngeal pouches that means that they are of endodermal orgin... how come they are always classified as of neural crest cell origin?? is it migration thing or what??
Can any one explain please
in Kaplan's home study program it is mentioned that there is a 5th phayrngeal pouch that forms the ultimobranchial bodies which give rise to calcitonin secreting parafollicular (C) cells of the thyroid.
but in High Yield embryology... it is mentioned that the 5th pharyngeal pouch completely regresses in human and that the ultimobranchial bodies come from the ventral wing of the 4th pharyngeal pouch (which is against what is written in kaplan)... which one is correct???
second thing... whether the parafollicular cells (which are rised from ultimobranchial bodies of endodermal orgin) are originated from the 4th or 5th pharyngeal pouches that means that they are of endodermal orgin... how come they are always classified as of neural crest cell origin?? is it migration thing or what??
Can any one explain please