Embryology Flashcards
what side of the trilaminar disc is the amniotic cavity on?
the dorsal side, the side of the ectoderm
what side of the trilaminar disc is the yolk sac on?
the ventral side, side of the endoderm
what forms at the two areas of the trilaminar disc where there is no mesoderm and the ectoderm and the endoderm are connected?
the mouth and anus
what leads to the axis formation in the embryo?
the notochord formation
describe the formation of the neural tube
the notochord sends out signals to the ectoderm causing it to thicken, this forms the neural plate in the midline. this plate sinks downwards so there are crests on either sides (like two hills and a valley). these two sides join up in the midline forming the neural tube
what do some of the cells in the crest of the neural fold do?
they proliferate rapidly and separate to form the neural crest cells and migrate to form a variety of structures.
in the head and neck region what do the neural crest cells mix with?
the mesoderm
what are somites derived from?
the paraxial mesoderm
what sort of structures do somites form?
axial skeleton bones and muscle
how many somites develop in human embryos?
around 33
what are the pharyngeal/brachial arches?
a series of arches which develop around the future mouth and pharynx
what supports the primitive pharynx?
the pharyngeal/brachial arches
how many brachial arches develop in humans?
5
what brachial arch disappears resulting in five brachial arches being present in development?
number 5
what lines the outside of the brachial arches?
ectoderm
what forms the clefts between the brachial arches?
the ectoderm
what is in the middle of the brachial arches?
the mesoderm and the neural crest cells
what does the mesoderm in the brachial arches go onto form?
cartilage and muscle
what is on the inside of the brachial arches?
endoderm
what forms the pouches between the arches?
endoderm