Embryo 1 and 2 Flashcards Preview

Musculoskeletal System > Embryo 1 and 2 > Flashcards

Flashcards in Embryo 1 and 2 Deck (24)
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1
Q

sources of bone besides sclerotome

A

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

2
Q

The dermomyotome splits to give rise to the _________ and ________, and each of these gives rise to

A

The dermatome gives rise to dermis and subcutaneous tissue

The myotome gives rise to muscle

3
Q

Myotome Shift: two muscle groups are formed (differentiate ventral and dorsal)

A

Dorsal– Epaxial (dorsal rami innervation)- back

Ventral– hypaxial (ventral rami)- body wall and limb

4
Q

The notochord regresses, but persists to form the __________; mesenchyme forms the ________

A

Nucleu Pulposus, vertabrae

5
Q

Importance of vitamin A

A

Retinoic acid which signals SHH and dictates the placement of digits

6
Q

on day ___ gastrulation occurs in which the ___ cells proliferate and migrate through the ________ between the epiblast and hypoblast, forming the following three layers:

A

16, epiblast, primitive streak, Endoderm, intraembryonic mesoderm and ectoderm

7
Q

on day ____ neurulation occurs, in which the ______ divides into the following 3 divisions:

A

22, intraembryonic mesoderm, Paraxial, Intermediate, and lateral plate mesoderm

8
Q

does the cranial or caudal end of neural tube close first

A

cranial, then caudal

9
Q

Paraxial mesoderm organizes into _____ and then ______ which eventually becomes the ____________

A

somitomeres, somites, axial skeleton and skeletal muscle

10
Q

Somites by region, on what day do they appear for sure

A

4, 8, 12, 5, 5, 8-10, 35

11
Q

Which somites disappear

A

1st occipital and last 7 coccygeal

12
Q

The sclerotome gives rise to ____

A

cartilage and bone

13
Q

Somites differentiate into ______ and _______

A

Sclerotomes and dermomyotome

14
Q

Myotome shifts dorsal to form

A

epaxial/back muscles

15
Q

Myotome shifts ventral to form

A

hypaxial/body wall and limb muscles

16
Q

Upper limb buds appear by Day __

Lower limb buds by Day __

A

26, 28

17
Q

contributes to: bones, tendons, ligaments, cartilage, fascia, joints, vessels, and dermis and is derived from the _______

A

mesenchyme, somatic layer of the lateral plate mesoderm

18
Q

_____induces proliferation of underlying mesenchyme and causes adjacent mesenchyme to remain undifferentiated

A

AER

19
Q

Mesenchymal cells aggregate at the posterior margin of the limb bud forming a

A

ZPA

20
Q

Mesenchyme condenses to form digital rays by the ___ week for hands and by the ___ week for feet

A

6th, 7th

21
Q

bone formation begins in the ___ week

A

8th

22
Q

The axial artery (not axillary!) becomes the _______and continues as the ___________

A

brachial , common interosseous

23
Q

Through growth of new vessels and regression of others the primary axial artery is represented by:

A

profunda femori, popliteal, posterior tibial

24
Q

what is the critical period for limb anomalies

A

4-5th week