Embryo 1 and 2 Flashcards
sources of bone besides sclerotome
Somatic layer of lateral plate mesoderm: sternum and limb bones
Neural crest: bones of the skull
Head somitomeres forms the cranial vault and base of skull
The dermomyotome splits to give rise to the _________ and ________, and each of these gives rise to
The dermatome gives rise to dermis and subcutaneous tissue
The myotome gives rise to muscle
Myotome Shift: two muscle groups are formed (differentiate ventral and dorsal)
Dorsal– Epaxial (dorsal rami innervation)- back
Ventral– hypaxial (ventral rami)- body wall and limb
The notochord regresses, but persists to form the __________; mesenchyme forms the ________
Nucleu Pulposus, vertabrae
Importance of vitamin A
Retinoic acid which signals SHH and dictates the placement of digits
on day ___ gastrulation occurs in which the ___ cells proliferate and migrate through the ________ between the epiblast and hypoblast, forming the following three layers:
16, epiblast, primitive streak, Endoderm, intraembryonic mesoderm and ectoderm
on day ____ neurulation occurs, in which the ______ divides into the following 3 divisions:
22, intraembryonic mesoderm, Paraxial, Intermediate, and lateral plate mesoderm
does the cranial or caudal end of neural tube close first
cranial, then caudal
Paraxial mesoderm organizes into _____ and then ______ which eventually becomes the ____________
somitomeres, somites, axial skeleton and skeletal muscle
Somites by region, on what day do they appear for sure
4, 8, 12, 5, 5, 8-10, 35
Which somites disappear
1st occipital and last 7 coccygeal
The sclerotome gives rise to ____
cartilage and bone
Somites differentiate into ______ and _______
Sclerotomes and dermomyotome
Myotome shifts dorsal to form
epaxial/back muscles
Myotome shifts ventral to form
hypaxial/body wall and limb muscles
Upper limb buds appear by Day __
Lower limb buds by Day __
26, 28
contributes to: bones, tendons, ligaments, cartilage, fascia, joints, vessels, and dermis and is derived from the _______
mesenchyme, somatic layer of the lateral plate mesoderm
_____induces proliferation of underlying mesenchyme and causes adjacent mesenchyme to remain undifferentiated
AER
Mesenchymal cells aggregate at the posterior margin of the limb bud forming a
ZPA
Mesenchyme condenses to form digital rays by the ___ week for hands and by the ___ week for feet
6th, 7th
bone formation begins in the ___ week
8th
The axial artery (not axillary!) becomes the _______and continues as the ___________
brachial , common interosseous
Through growth of new vessels and regression of others the primary axial artery is represented by:
profunda femori, popliteal, posterior tibial
what is the critical period for limb anomalies
4-5th week
