How Do the Face-Building Cells Get to the Right Place?
Developmental domain · Lesson 4 of 20 · Principles of Biomedical Science (PBS)
Today's goal: Describe how cranial neural crest cells migrate in organized streams from the neural folds into the frontonasal process and the pharyngeal arches, and explain why correct migration is required to fill the facial prominences on schedule.
What a finished product looks like
This is a model of the work you should turn in. Use it to check your own: match the structure and the level of detail, do not copy it. Your wording should be your own.
Three labeled arrows from the neural folds:
- Forebrain/midbrain crest into the frontonasal process (midface, top of the nose).
- First-arch stream into the first pharyngeal arch (becomes the maxillary and mandibular processes).
- Hindbrain streams into the second and later arches (other neck and face structures).
Circled: the frontonasal process and the first arch, because they supply the lip-building prominences.
Consequence: If the maxillary-bound stream were short by half, the maxillary process would be hypoplastic (under-grown), which could leave a gap because it cannot reach across to fuse with the medial nasal process.
How this was built, step by step
The finished product above did not appear all at once. Here is the path from the question to the turned-in work, so you can follow the same steps.
- 1Start from today's question: How do cranial travel from the neural folds to the right facial blocks, and why does taking the correct route matter?
- 2Work the Model and the Explore questions to reason it out before writing anything.
- 3Pull the specific evidence the product needs from the reading and any database you used.
- 4Write it up in the required format: On a side-view sketch of the early , draw three arrows from the neural folds to the three destinations and label each. Circle the two destinations that supply the upper-lip prominences. Then finish a sentence with a real consequence: if the maxillary-bound stream were short by half, the would be ____, which could leave a gap because it cannot ____.
- 5Check it against the rubric, then submit.
| Criterion | Proficient | Developing | Beginning |
|---|---|---|---|
| Complete | Every required part of the artifact is present and filled in. | Most parts are present, but one is missing or left blank. | Several parts are missing. |
| Accurate | The science and data are correct and match the evidence. | Mostly correct, with a small factual slip. | Key science or data is wrong. |
| Scientific reasoning (CER) | States a claim, backs it with specific evidence, and explains the reasoning. | Has a claim and evidence, but the reasoning is thin or missing. | Gives an answer with no evidence or reasoning. |
| Professional communication | Clear, organized, and labeled the way a clinician or scientist would write it. | Readable but disorganized or missing labels. | Hard to follow. |
| Submitted | Turned in the right way (Schoology for routine work) and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
- CompleteProficient: Nothing is left blank: the model fills every part of "On a side-view sketch of the early embryo, draw three arrows from the neural folds to the three destinations and label each. Circle the two destinations that supply the upper-lip prominences. Then finish a sentence with a real consequence: if the maxillary-bound stream were short by half, the maxillary process would be ____, which could leave a gap because it cannot ____.".
- AccurateProficient: Every number and claim matches the case evidence.
- Scientific reasoning (CER)Proficient: It names a claim, cites the specific evidence, and explains the reasoning, not just the answer.
- Professional communicationProficient: It is organized and labeled like a real chart note.
- SubmittedProficient: It would be turned in on Schoology and confirmed.
WebXam problem for today's skill
One exam-style question that uses exactly what you practiced today. Try it before you reveal the answer, then read why each choice is right or wrong.
Tap an answer to see the full explanation. Nothing is recorded or graded.