How the Palate Begins: Secondary Palatal Shelf Outgrowth
Take the reading one piece at a time. For each piece: read it once, underline the sentence that says what happens, then look up any word in the list. Tap a word to see its definition.
Piece 1 of 2
Pull the craniofacial timeline. The primary palate (front triangle) forms at human weeks 5 to 6 (mouse about E11.5). At about week 6 (mouse about E11.5 to E12.5) the secondary palatal shelves grow out vertically beside the tongue: two shelves bud from the maxillary processes and point downward, like two curtains hanging on each side of the tongue. Later (week 8, Lesson 7) they will elevate to horizontal.
Piece 2 of 2
Scientists studied a mouse missing the gene Msx1. In normal mice the front of the palatal shelves grows by adding many new cells. In the Msx1 mutant the front of the shelf had too few dividing cells, the shelf stayed too small, and the palate ended up cleft. When the team added back a single growth signal (Bmp4) in the shelf, normal growth and a closed palate were rescued. So a palatal shelf is not just there; it is a block of tissue that must actively grow to the right size, and growth depends on signals telling cells to divide.
Reading the Research
- 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.
Now put it together: In one or two sentences, say what this whole reading is telling you about Mateo. Then go back to the lesson and fill in the guided notes.