
Locate epiblast on this anatomical reference. Read the original plate labels to confirm the view and adjacent structures.
Zoom in, then drag to inspect. Keyboard: + / − to zoom, arrows to pan, 0 to reset. Tap the numbered markers to explore parts.
germ layers: labelled anatomical figure. Original source colours and labels retained.
Image: OpenStax / University of Hawaiʻi adapted teaching figures; original contributors credited at source · Source / original · CC BY 4.0 — figure credits at sourceNumbered markers and focused views are Mediveerse learning overlays; the original reference is linked above.
Primitive streak and gastrulation
Understand what you see.
Gastrulation establishes definitive ectoderm, mesoderm and endoderm and key body axes.
Zoom into the original labels. Practise pointing out each structure, then explain it aloud. Diagrams are teaching references; specimen appearance and slide staining vary.
How to recognise it.
- Midline epiblast thickening
- Appears caudally during week three
- Ingressing cells establish germ layers
Point them out.
Tap a number to open its reference, zoom in and locate the structure. Numbers stay the same across views. This key follows landmarks visible in the reference images.
Think first. Then reveal.
Say your answer aloud before opening the suggested response.
01How do you identify primitive streak and gastrulation?+
Midline epiblast thickening. Appears caudally during week three. Ingressing cells establish germ layers.
02Which cells form all three definitive germ layers?+
Epiblast cells. Ingressing cells replace hypoblast to form definitive endoderm and form intraembryonic mesoderm; remaining epiblast is ectoderm.
03When does the streak normally regress?+
It regresses as gastrulation progresses; persistent remnants may be associated with sacrococcygeal teratoma.
04Which structures should you point out on this reference?+
Primitive node; Primitive groove; Epiblast. Gastrulation establishes definitive ectoderm, mesoderm and endoderm and key body axes.
Read the references.
Credited anatomical plates, microscopy and university teaching references. Individual image credits appear below the viewer. Historical plates can use older terminology; use the lesson text for current names.