Term
| What is the membrane that becomes the mouth area and mouth? |
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Definition
buccopharyngeal membrane - area
prechordal plate - mouth |
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Term
| What is the membrane that becomes the anus? |
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Definition
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Term
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Definition
| Depression in the primitive streak; Site along which cells migrate through the epiblast |
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Term
| In what order do the cells migrate through the primitive groove? |
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Definition
| endoderm first; mesoderm next; non-ingressing cells are ectoderm |
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Term
| What affects developmental cell fate? |
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Definition
| Location and timing of ingression through the primitive groove. |
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Term
| How does BMP4 and FGF affect mesoderm? What does inhibition of BMP4 do? |
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Definition
BMP4 and FGFs ventralize mesoderm into intermediate and lateral plate mesoderm;
Inhibition dorsalizes mesoderm to form notochord and somitic mesoderm (paraxial mesoderm) - The node secretes BMP antagonists which inhibit BMP4 and dorsalizes adjacent mesoderm |
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Term
| What determines left and right sides? |
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Definition
| FGF8 induces nodal on left side; SHH and Lefty1 block nodal on right |
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Term
| What are 5 roles of the notochord? |
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Definition
- defines our body axis
- defines our phylum (chordata)
- provides rigidity to the embryo
- signaling center to induce neural fates
- precursor for the axial skeleton
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Term
| Describe formation of the neural tube. |
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Definition
- Dorsal ectoderm is specified to become neural plate
- Lateral edges become elevated to form neural folds and mid region becomes depressed to form the neural groove
- Neural folds move toward each other and fuse to form the NT
- NT detaches from overlying ectoderm
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Term
| Describe fusion of the NT. |
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Definition
| Fusion begins in the middle at the 5th somite and proceeds in both directions (cranial and caudial) |
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Term
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Definition
| Cranial and caudal; transient openings at either end of the NT |
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Term
| When is neurulation complete? |
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Definition
| ~27 days when neuropores close |
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Term
Neural tube defects and examples
What is important for formation of the NT? |
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Definition
Occur when there is incomplete fusion of the neuropores; ex. spina bifida and anencephaly
folic acid, cholesterol, and numerous genes |
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Term
| What induces the neural plate formation? |
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Definition
| SHH from the notochord induces floor plate (ventral NT fates) - which becomes a source of SHH; BMPs from surrounding ectoderm (dorsal NT fates) |
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Term
| Describe formation of the neural crest and cell fates. |
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Definition
| Neural crest is formed by the dorsal most portion of the NT; cells at the lateral borders of the neural plate ectoderm dissociate from neighbors and undergo epithelial-mesenchymal transformation and migrate away from NT. Mesenchymal neural crest migrate through the mesoderm to form a wide variety of tissues. |
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Term
| What are the 4 neural crest cells regions (describe later)? |
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Definition
- cranial
- cardiac
- vagal/sacral
- trunk neural crest
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Term
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Definition
| migrate dorsolaterally to produce craniofacial mesenchyme; differentiates into cartilage, bone, neurons, glia, and connective tissue of face. Some enter pharyngeal arches, contribute to thymus, tooth primordia and middle ear/ jaw bones |
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Term
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Definition
| give rise to outflow tract septum (separating pulmonary/aortic circulations) and smooth muscle around large arteries arising from heart |
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Term
| vagal/sacral neural crest |
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Definition
| gives rise to parasympathetic ganglia of gut |
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Term
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Definition
Dorsolateral migrating trunk neural crest give rise to melanocytes;
Ventromedial migrating trunk neural crest (through anterior somite) form the dorsal root ganglia/nerves |
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Term
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Definition
- axial/ chordamesoderm
- paraxial mesoderm
- intermediate mesoderm
- lateral plate mesoderm
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Term
| What does axial/chordatamesoderm give rise to? |
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Definition
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Term
| What does paraxial mesoderm give rise to? |
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Definition
| head and somite (sclerotome - cartilage, myotome - skeletal muscle, dermatome - dermis) |
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Term
| What does intermediate mesoderm give rise to? |
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Definition
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Term
| What does lateral plate mesoderm give rise to? |
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Definition
parietal mesoderm (somatic) - with overlying ectoderm forms lateral and ventral body walls and thin serous membranes lining the body cavities
visceral mesoderm (splanchnic) with endoderm will form gut wall and thin serous membrane around each organ
visceral mesoderm of yolk sac differentiates into angioblasts |
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Term
| What does endoderm give rise to? |
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Definition
GI tract, epithelial lining of the lung buds and trachea, liver, gall bladder, and pancreas
hindgut and foregut |
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