Developmental Histo - Musculoskeletal Dvlpmt

Front 1

mesenchymal origins of axial skeleton and musculature(4)

Back 1

1)somites
2)intermediate mesenchime (nephrotome):kidney
3)lateral plate mesenchyme
4)notochord - nucleus pulposus of intervertebral disk

Front 2

derivitives of somites(3)and what they become

Back 2

1)dermatome- dermis of skin
2) myotome - skeletal mm
3)sclerotome - vertebrae, disc (annulus fibrosis, & ribs

Front 3

what makes up the lateral plate of the mesenchyme and what does it become

Back 3

1) splanchnopleure - smoothmuscle of gut
2) somatopleure - appendicular skeleton and vasculature

Front 4

intramembraneous bone development

Back 4

primarily in skull

Front 5

endochondral

Back 5

intracartilagenous, most bones except the skull

Front 6

describe bone bone formation from 4th week on

Back 6

4th week - mesenchyme migrates to area
5th week mesenchyme condences
6th week - chondrification
7-12 weeks - ossification of primary centers
bith to 9nd year - ossification of secondary centations and formation of epiphyseal plates
18th-25th year - fusion of epiphyseal plates and end of bone growth

Front 7

Development of vertebrae

Back 7

Vertebrae arise from sclerotome, which is the most medial part of the somite.
Each vertebral segment derives from a part of two separate somites.
These come together to form a single vertebra.
The intervertebral disk derives from mesoderm remaining behind after mesodermal migration.

Front 8

spinal bifida

Back 8

late closure of caudal neuropore results in delay of inductive signal for neural arch, until the point where mesenchyme is not responsive to such a signal (hence, no neural arch forms)

Front 9

hemivertebra

Back 9

failure of sclerotome to divide and migrate resultin gin an abnormal vertebral segment -- scholiosis

Front 10

origin of body wall musculature

Back 10

myotomes (of somite)

Front 11

how do myotomes differentiate

Back 11

they differentiate into myoblasts during emryonic period which fuses to form skeletal mm in fetal division

Front 12

2 primary devisions of dermomyotome

Back 12

1)epaxial
2)hypaxial

Front 13

epaxial

Back 13

exclusively myotome - forms deep back mm and is innervated by dorsal rami of spinal nerves

Front 14

hypaxial

Back 14

from dermatome portion of dermomyotome - travels adjacent to somatopleure and contributes to appendicular and body wall musculature. it is innervated by ventral rami of spinal nn

Front 15

what is the pattern of nn mm association

Back 15

myoblasts develop 1st in the 4th-5th week. Axons then grow out of CNS in 5th week and follow the migrating myoblasts. Axons divide into preaxial (flexor) and postaxial (extensor) groups of mm. Axons begin migration to their final location during the 5th to 6th week. Aroudn the 17th -10th week. mm begin to function and we see movement of limbs. Around 2 years postanat you have myelination of lower extremities.

Front 16

Hypaxial myoblasts differentiate themselves from epaxial by a process called _________

Back 16

delamination

Front 17

developemnt of upper limb of appendicular skeleton occers in a ___________ rotation

Back 17

lateral (outward)

Front 18

developemnt of lower limb of appendicular skeleton occers in a ___________ rotation

Back 18

medial (inward)

Front 19

preaxial (fx, innervation)

Back 19

flexors, ventral

Front 20

postaxial (fx, innervation)

Back 20

extensors, dorsal

Front 21

syndactily

Back 21

fusion of digits (failure of appropriate cell death)

Front 22

polydactily

Back 22

extra digits (abnormal induction of a 6th digit)

Front 23

amelia

Back 23

absense of a limb

Front 24

meromelia

Back 24

absence of part of a limb

Front 25

lobster-claw hand

Back 25

absence of 3rd digit, fusion of 4th & fith

Front 26

hypomere mesoderm migrates ______ to somatopleure

Back 26

superficial ( so mm superficial to bone)