Clue 1: Orient yourself
What blocks the bridge before the boat clears?
Use the labels and the picture's left-to-right, near-to-far, or before-and-after order. Name only what you can point to.
The question
What blocks the bridge before the boat clears?
Why it matters: The face forms through a timed sequence of growth, movement, and joining. Locating the missed step helps researchers ask a testable question instead of treating every cleft as the same process. Today you practice the professional reasoning behind that work: Palatal shelves must rapidly elevate above the tongue, and jaw-tongue geometry can block that movement.
On your WebXam
Using Pierre Robin sequence to show a cleft can arise from a mechanical block, not a palate gene
For life
When something appears after you remove a signal, look for the brake that was holding it down.
Principle: Held down, not gone
Five principles we return to
Having it is not using it
Same instructions, different switches
Same look, different cause
Change one thing and watch
Boss or doorman?
Decides the result or only allows it
Held down, not gone
Remove the brake and it returns
Many roads, one ending
One result can begin many ways
Try the everyday version first
Drawbridges rotate only after a boat clears
A drawbridge changes position around a hinge. It can move safely only when the path is clear and the lifting parts act in the correct order.
Do not jump to the biology yet. Treat the picture as a small system. Track its parts, follow one change at a time, and keep more than one explanation open until the picture supplies a way to separate them.
Clue 2: Trace one change
Which movement changes the bridge from vertical to horizontal?
Follow one object, stage, or path. Point to the first place where the situation changes instead of jumping to the ending.
Clue 3: Keep the cause open
Could intact bridge parts still fail to meet?
List more than one explanation that still fits. Name the extra observation that would help you separate those possibilities.
Now inspect the illustration
Work from the visible evidence. A useful answer names the part of the picture that supports it and leaves unknown causes open.
- 1What blocks the bridge before the boat clears?
- 2Which movement changes the bridge from vertical to horizontal?
- 3Could intact bridge parts still fail to meet?
Tier 1 check
Finish with the everyday model
Use the everyday picture to answer today's question in plain words: What blocks the bridge before the boat clears?
You can complete today's required check without opening the technical details below.
Ready for the real names? Optional tier 2
Technical rules and limits
Rule 1: A structure may need room before it can move.
Rule 2: Shape change can be rapid and coordinated.
Rule 3: A mechanical block can cause failure without missing parts.
Where the analogy stops: Palatal elevation is driven by tissue forces and growth, not hinges.
Carry the previous idea forward
The secondary palate begins as paired shelves whose cell growth must create enough tissue to reach the midline.
Today's technical takeaway
Palatal shelves must rapidly elevate above the tongue, and jaw-tongue geometry can block that movement.
Now map the same rules onto biology
Use jaw and tongue position to explain shelf elevation
Boat clears the channel
Tongue descends as jaw space increases
Bridge leaf rotates
Palatal shelf elevates
Blocked bridge
Small jaw and high tongue can prevent elevation
Educational illustration, not a clinical photograph. Use the labels and evidence cards to make the biological claim.
Mateo's case file: evidence supplied in this lesson
DEV07-E1
Palatal shelves first grow vertically beside the tongue.
Why it matters: Their early position is not the final roof position.
DEV07-E2
The shelves elevate to a horizontal position above the tongue.
Why it matters: Movement is required before midline contact.
DEV07-E3
A small jaw can keep the tongue high and mechanically block elevation.
Why it matters: Geometry can cause cleft palate even when shelves exist.
Make the clinical decision
You are reviewing two fetal MRI teaching diagrams.
Diagram A shows shelves present but vertical beside a high tongue. Diagram B shows shelves horizontal above the tongue.
AIdentify elevation failure in A and completed elevation in B.
BCall both diagrams identical because shelves are present.
CDiagnose a named syndrome from shelf position alone.
Choose the comparison and cite the evidence that separates presence from position.
Evidence required
DEV07-E1 + DEV07-E2 Claim ceiling
You may identify a mechanical elevation problem. You may not assign a syndrome without the full clinical pattern.Go deeper Optional tier 3
Everything required for today is above. Open these only if you want the explainer, source trail, or download files.
The everyday model and Tier 1 check are the complete required path for this lesson.
Use these checks to keep your place. They are not turned in through the portal.
Check off as you finish
- Worked through the everyday picture and answered its three questions.
- Completed the Tier 1 check in plain words.
Turn in: Developmental lesson 7: Getting Above the Tongue: Palatal Shelf Elevation
Go to Schoology to turn this in.
Submit one PDF. Put your first and last name in the document header. Name the file: FirstName LastName - Assignment Title - YYYY-MM-DD.pdf.
Open Schoology PDF upload helpIf you cannot get in, see Mr. Mendoza. Do not skip the work.
Optional legacy technical materials Open only if you want the original notes, vocabulary, artifact, and CER work
Before this page, you should know
- The roof of the mouth behind the lip is the secondary ; it begins as two palatal shelves that bud from the maxillary processes at about human week 6.
- The shelves first grow vertically (downward), one on each side of the tongue, and are made mostly of neural-crest-derived .
Today's new idea is only
Elevation needs two things at once: the shelf must remodel from the inside AND the space above the tongue must open up, and blocking either one leaves the shelves vertical and the .
Goal: Explain how the vertical palatal shelves rotate to a position above the tongue, and identify one mechanical and one cause of failed elevation.
Know by the end
- Elevation is the step where each vertical rotates to above the tongue at about human week 8.
- Elevation depends on internal remodeling of the shelf, including the water-holding matrix molecule , plus external room as the tongue descends and the head grows wider.
- A cause of failed elevation is a shelf that cannot remodel; a mechanical cause is something blocking the path.
- In a small jaw holds the tongue up, mechanically blocking elevation, and about 85 percent of these babies have a even when palate genes are normal.
1
The rotation
Model start: The second act of building is elevation: each vertical rotates to a position above the tongue at about human week 8.
- Elevation is a fast remodeling of the shelf's inside; a key matrix molecule is ____, which holds water and swells the .
- At the same time, the ____ (tongue) descends and the head grows wider, opening room above the tongue.
2
Two kinds of failure
- A ____ reason: the shelf itself cannot remodel properly (matrix or problems).
- A ____ reason: something blocks the path, classically a small jaw holding the tongue up ().
3
Crossing one possibility off for Mateo
- In Pierre Robin a ____ holds the tongue up, and about 85 percent of these babies have a .
- If Mateo's jaw and tongue are normal, we can ____ the mechanical (Pierre Robin) explanation and keep looking at other steps.
Everything you need for today is on this page. These links are optional.
What to read
Read the short plain-language explanation written for this lesson. Plain-language explainer for this lesson
Why this source matters
This explanation gives you the background for today's idea without making you decode a research paper: Elevation needs two things at once: the shelf must remodel from the inside AND the space above the tongue must open up, and blocking either one leaves the shelves vertical and the .
Words to unlock first
elevationhorizontalverticalhyaluronanPierre Robin sequence
Reading moves
- Skim the title and abstract first to get the gist.
- Circle the one sentence that states the main claim.
- Box the evidence the authors give for that claim.
- Mark one sentence that confuses you, and move on.
Stop point
Stop after the final 'Use it now' section. The research citations are available separately for advanced readers.
Your output
Write one claim-evidence sentence: state the main idea, then name the example or evidence that supports it.
Where this fits
Tested on (Ohio WebXam)
Genetics of Disease · 072130
PLTW lesson
MI · Developmental domain · Interacting structures and movement in development (shelf elevation)
WebXam domain
Molecular and Genetic Technology
Evidence to produce
Add the "Act 2: Elevation" entry to Mateo's developmental chart: describe the position change, name one tissue cause and one mechanical cause of failed elevation, then make a call about the small-jaw (Pierre Robin) route for Mateo given his normal jaw and otherwise normal exam, and note what your decision rules out.
Lab / skill
Principles of Biomedical Science (PBS) · Human Body Systems (HBS)
Everything required for today's decision is already in the case file and plain-language explainer. The links below are original papers and database records for teachers and advanced readers, not assigned student reading.
- Claim: For the palatal shelves to elevate, two things must happen: ____ and ____.
- Evidence: In , a ____ holds the tongue up, and about ____ percent of these babies have a .
- Reasoning: This matters for Mateo because if his jaw and tongue are normal, we can ____ the mechanical (Pierre Robin) explanation and keep looking at other steps.
How this is graded (rubric)
For: Add the "Act 2: Elevation" entry to Mateo's developmental chart: describe the position change, name one tissue cause and one mechanical cause of failed elevation, then make a call about the small-jaw (Pierre Robin) route for Mateo given his normal jaw and otherwise normal exam, and note what your decision rules out.
| 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 through the route named under Submit here and confirmed. | Turned in, but in the wrong place or unconfirmed. | Not turned in. |
How the model answer scores against this rubric
- CompleteProficient: Nothing is left blank: the model fills every part of "Add the "Act 2: Elevation" entry to Mateo's developmental chart: describe the position change, name one tissue cause and one mechanical cause of failed elevation, then make a call about the small-jaw (Pierre Robin) route for Mateo given his normal jaw and otherwise normal exam, and note what your decision rules out.".
- 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 attached to your class form or handed in, and confirmed.
What's next: The shelves remodel and rise above the tongue once the tongue drops and the head widens. But now the two shelves sit almost edge to edge at the , still separate. What actually lets two separate edges of become one continuous roof? We chase that next time.