A pharyngeal groove (or branchial groove, or pharyngeal cleft
) is made up of ectoderm unlike its counterpart the
pharyngeal pouch on the
endoderm
Endoderm is the innermost of the three primary germ layers in the very early embryo. The other two layers are the ectoderm (outside layer) and mesoderm (middle layer). Cells migrating inward along the archenteron form the inner layer of the gast ...
al side.
The first pharyngeal groove produces the
external auditory meatus
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter.
Stru ...
(ear canal).
The rest (2, 3, and 4) are overlapped by the growing 2nd
pharyngeal arch
The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arche ...
, and form the floor of the depression termed the
cervical sinus, which opens ventrally, and is finally obliterated.
See also
*
Branchial cleft cyst
A branchial cleft cyst is a cyst as a swelling in the upper part of neck anterior to sternocleidomastoid. It can, but does not necessarily, have an opening to the skin surface, called a fistula. The cause is usually a developmental abnormality aris ...
References
Animal developmental biology
Pharyngeal arches
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