Term
| when is the bilayer and trilayer embryoblast estabilished, respectively? |
|
Definition
| 2nd and 3rd week of gestation |
|
|
Term
| what is caudal dysplasia and what results from it? |
|
Definition
| failure of gastrulation to complete, can result in fused lower limbs |
|
|
Term
| cell of epiblast ingress through the primitive streak to become what? |
|
Definition
| endoderm (replacing hypoblast) and mesoderm |
|
|
Term
| what is a sacrococcygeal teratoma? |
|
Definition
it is the failure of primitive streak to properly degenerate at the end of gastrulation
It is derived from multipotent cells, so leads to diverse tissue types in the caudal region |
|
|
Term
| what are the three neural tube defects we learned? |
|
Definition
| spina bifida, anencephaly, and meningoencephalocele |
|
|
Term
| what causes spina bifida? |
|
Definition
| failure of posterior neuropore to close and/or vertebral neural arch defect |
|
|
Term
| what causes anencephaly and meningoencephalocele? |
|
Definition
| failure of the anterior neuropore and/or skull to close |
|
|
Term
| what does the paraxial mesoderm give rise to? |
|
Definition
| bone/cartilage, muscle, dermis |
|
|
Term
| what does the intermediate mesoderm give rise to? |
|
Definition
| urinary system and gonads |
|
|
Term
| what does the lateral plate mesoderm give rise to? |
|
Definition
| coelom space arises surrounded by somatic (limb skeleton) and splanchnic (most of gut except lining) layers |
|
|
Term
| what does the endoderm give rise to? |
|
Definition
| mucosa or ducts of the GI tract, lungs, liver, gallbladder, pancreas, urinary bladder |
|
|
Term
| intramembranous ossification |
|
Definition
| direct ossification of mesenchyme |
|
|
Term
| endochondral ossification |
|
Definition
| formation of cartilaginous template that is replaced by bone |
|
|
Term
| what does the skeleton develop from? (3) |
|
Definition
| paraxial mesoderm (somites), somatic layer of the lateral plate mesoderm, neural crest |
|
|
Term
| what does the paraxial mesoderm (somites) form? |
|
Definition
| base of skull, vertebrae, and ribs |
|
|
Term
| What does the somatic layer of the lateral plate mesoderm form? |
|
Definition
|
|
Term
| what does the neural crest form? |
|
Definition
| facial bones and cranial vault |
|
|
Term
|
Definition
| from 4 sclerotomes (2 on each side, split into cranial and caudal pieces on each side of the spine); form intersegmentally |
|
|
Term
| what drives cervical, thoracic, etc. vertebra differentiation? |
|
Definition
|
|
Term
| what does the neural tube form for the spine? |
|
Definition
|
|
Term
| what does the notochord form for the spine? |
|
Definition
|
|
Term
|
Definition
| only 2 ossification centers in a vertebrae; can cause improper dev. and scoliosis (ossification center doesn't form or somites/sclerotomes divide improperly |
|
|
Term
| myotomal cells separate from the dermamyotome to form XXX dorsally and XXX ventrally |
|
Definition
|
|
Term
| what does the apical ectodermal ridge do? |
|
Definition
| influences new cells to be added to the distal ends of limbs |
|
|
Term
| what is the amelia condition? |
|
Definition
| congenital absence of a limb likely resulting from failure of limb outgrowth |
|
|
Term
| what is the phocomelia condition? |
|
Definition
| acute, temporary failure of limb outgrowth; limb lacks intermediate elements; can be caused by teratogens |
|
|
Term
| what is polydactyly and how is it caused? |
|
Definition
| digit duplications caused by errors in preaxial-postaxial patterning |
|
|
Term
| what is syndactyly and how is it caused? |
|
Definition
| fusion of adjacent digits - can be caused by absent cell death or lack of AER regression |
|
|
Term
| dorsal side of the lower limb ends up where when the child is born? |
|
Definition
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