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The Embryonic Disk Overview Structure & content Study tools Technical notes For teaching staff New in this version Users & comments


Text and images
© Jeremy Cook 1997–2008




Hypertext glossary


Study tools : 2
Animations and self-assessment

Animations: the flexibility of ToolBook allows us to go beyond the text, diagrams and photographs found in printed books to offer animations of developmental processes.

Many sequences, such as those showing embryonic folding and neurulation, heart folding and palatal closure, appear in viewers with reversible ‘video’ controls and time-lines.Other animated diagrams move spontaneously as soon as they are visible.

Animations include:

  • Lacunar flow in the early placenta
  • Migration of epiblast cells in gastrulation
  • Primitive streak, notochord, neural plate
  • Folding of the primitive heart tube
  • Longitudinal folding of the embryo (day 14-35)
  • Lateral folding and somite dispersal
  • Remodelling of the primitive pharynx
  • Cell cycle mini-game: why are germ cells immortal?
  • Migration of primordial germ cells
  • Maturation of ovarian follicles
  • Thyroid migration and remodelling of pharyngeal pouches
  • Elongation of posterior lens fibres
  • Formation of the secondary palate
  • Splitting an opening by intussusception
  • Ascent of the kidney
  • Rotation of the ventral pancreatic bud

Self-assessment questions: 'The Embryonic Disk' includes a bank of over 1600 true/false question-pairs and associated explanations on gametogenesis, early development, organ and systems development and the germ line.

Topic and level are set by the student. Twenty questions at a time are chosen at random from a larger set, using a different ‘seed’ each time, and either a true or a false statement is presented for each question, again at random.

For teaching staff: the questions are based on a well-established bank developed by us for use at UCL, and they use a confidence-assessment approach to scoring that we have found to be valuable in helping students reflect on their knowledge. These questions may be copied and used for assessment purposes on certain easy-to-meet terms and conditions.