Embryology Flashcards
(29 cards)
What are the three germ layers
ectoderm, mesoderm, endoderm
What are the three primary structures of the development of the vertebral column
Notochord, mesodermal Semites, sclerotomes
What is another name for notochord
Chordae dorsalis
Where is the notochord derived from
Embryonic mesoderm
The notochord extends from the_________ to the _____.
Spheroid bone,coccyx region
The notochord represents the beginning of the ________ in all vertebrates
Axial skeleton
Where does the notochord first appear.
Narrow median rod of cells between the ectoderm and endodermhat is
What is the second step in the notochord process
Notochord then becomes surrounded by secondary mesoderm which becomes converted into the vertebral column
What is the last process in the notochord
The notochord disappears but its remnants become the nuclei purposes of the IVD
Where are somites located
Greek word meaning body, cuboidal bodies located around neural tube
Describe the mesodermal somites
Paired block-like formations lying on each side of the median line
What are the three differentiations of the mesodermal somites
myotomes, dermatomes, sclerotomes
What is the mesodermal stage marked by
1.mesenchymal condensation of the sclerotomes
What is the primordium marked by
Lower half of one sclerotome joins with the upper half of the sclerotome below.
Name the three directions that the mesoderm growths during primordium
- Medically to form the body
- Posteriorly around the neural tube to form the vertebral arch
- anterolaterally to form the TP’s and ribs
How is the intervertebral fissure formed
Becomes the IVD after mesenchymal tissue is forced into it
What are the three stages of vertebral development
Mesodermal, chondrification, ossification
When does the chondrification stage start and end
In the 4th week of embryonic development and ends in the 9th week
Where in the embryo does it start and what is happening
In the four centers: 2 in the body and 1 in each vertebral arch.
-begins laying down cartilage over the membranous vertebral column
When does primary ossification occur in the cervical, thoracic, and lumbar vertebrae
Occurs before birth
When does the second ossification occur in the cervical, thoracic and lumbar vertebrae.
After birth
Where are the Primary ossification centers in the cervical, thoracic and lumbar vertebrae
- 1 in vertebral body
- 1 in each vertebral arch (pedicle and lamina)
- One in each mammillary process
Where are the secondary ossification centers in the cervical, thoracic, and lumbar vertebrae
- 1 in each epiphyseal plate of the vertebral body.
- 1 in the tip of each transverse process
- 1 in the tip of the spinout process
Where are the ossification centers for the primary atlas
- 1 in vertebral body
- 1 in each vertebral arch
- Two in the odontoid process
