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Flashcards in embryo 2 Deck (51)
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1

sources of bone forming tissue

mesoderm
neural crest

2

Mesoderm/Neural crest cells revert to ________ state

mesenchymal

3

Mesenchymal cells will differentiate into ________ and _______ to eventually form bone

osteoblasts or chondroblasts

4

during intremembranous ossification: At first, bone is arranged in ______ , which will reorganize as ______

spicules, osteons

5

joint formation begins when as condensed mesenchyme appears in _______

joint interzones

6

what will form the tissue that unites the bones of a joint

Mesenchyme

7

3 types of joints

-Fibrous (ex: sutures)
-Cartilaginous (ex: costochondral joints, symphyses)
-Synovial (ex: knee joint)

8

during formation of synovial joints, Mesenchymal cells surrounding joint interzone form _______ and _______

form fibrous joint capsule & reinforcing ligaments

9

Condensed mesenchyme in joint inter zone gives rise to

Ligaments inside joint capsule, synovial membrane, menisci

10

Paraxial mesoderm (sclerotome) forms all of the ________ except for the _____ and portion of the ______

axial skeleton, sternum and portion of the skull

11

forming vertebrae and IV disc starts with what

Sclerotome cells surround neural tube and notochord

12

Each sclerotome segment has a _______ portion cranially and a ______ portion caudally

less dense, dense

13

half of dense forms what and other half combines with less dense and forms what

IV disc, vertebrea bodies

14

______ are formed from sclerotome of paraxial mesoderm. Grow out as lateral extensions of costal processes developing from thoracic vertebrae & wrap around anteriorly

Ribs

15

________forms where costal process meets vertebra

Synovial joint

16

Sternum is induced to form by ribs at ventral midline from ________

lateral plate somatic mesoderm

17

Develops as two sternal bars that will fuse cranially to caudally during _____ week

10th

18

Primary curvatures

(develop during fetal period): thoracic & sacral

19

secondary curvatures

(develop after birth): cervical (once can hold head up) & lumbar (once begins walking)

20

Neurocranial bones form from what and what are by what ossification process(s)

paraxial mesoderm and neural crest cells
intramembranous and endochondral ossification

21

visocranium bones form from what and by which ossification process(s)?

neural crest cells from first 2 pharyngeal arches, ONLY by intramembranous

22

_______ forms by endochondral ossification (base of skull: sphenoid, clivus, petrous portion of temporal bone) (red + blue = chondrocranium)

“Chondrocranium”

23

_______: forms by intramembranous ossification (all other parts of neurocranium)

“Membranous neurocranium”

24

Fontanelles

enlarged membranous spaces where 2+ bones meet

25

Sutures:

Fibrous joints uniting the flat bones of the skull
During fetal period, are membranous and flexible joints

26

Craniosynostosis

Premature closure of suture(s)

27

Scaphocephaly

(premature closure of sagittal suture)

28

Brachycephaly

(premature closure of coronal suture)

29

Lateral plate mesoderm -->

mesenchyme --> pectoral & pelvic girdles, limb bones, sternum (= appendicular skeleton + sternum)

30

Paraxial mesoderm (sclerotome) -->

mesenchyme -->vertebral column, ribs, + portion of neurocranium (occipital & parietal bones, petrous portion of temporal bone, posterior half of sphenoid bone)