development of the muscular system Flashcards
Myotome
Paraxial Mesoderm:
gives rise to all muscle except muscle in the eye
Sclerotome
Paraxial Mesoderm:
gives rise to the axial skeletone and cartilage
Dermatome
Paraxial Mesoderm:
give rise to dermis
Somites divisions
myotome
sclerotome
dermatome
Ventromedial part of the somite
Sclerotome
Dorsolateral part of the somite
Dermatome
myotome
what makes up the sclerotome
Cephalic Loose (upper) Caudal dense (lower) -packed mesenchymal cells
how are vertebral bodies formed
caudal half of sclerotome travels down to the cephalic 1/2 of the sclerotome moving up
caudal dense: gives rise to transverse processes and half the body and superior artivular process
cephalic loose: gives rise to half the body and spinous process and the inferior articular process
Nucleus pulposes
made from the notochord
Annulus Fibrosus
made from the fribrous tissue from the sclerotome
fibrocartilage
Ribs are mad from:
sclerotome cells that grow from the costal processes of thoracic vertebrae
costal cartilage also from sclertome
sternum derived from:
develops from the somatic layer of the lateral plate mesoderm
made from ribs and then medially join from either side
what are hox genes
help give rise to the shape of the bones in the vertebrae
Hox 4/5 give rise to:
cervical vertebrae
Hox 6 give rise to:
Ribs and thoracic
Hox 9 give rise to:
floating ribs
Hox 10 give rise to:
lumbar vertebrae
Hox 11 give rise to:
sacral vertebrae
Caudalization and examples
gain of function
transforms the vertebrae to look similar to the vertebrae below
Hox 6 in the cervical region to look like thoracic and have ribs
hox 10 in the thoracic cregion to look like lumbar vertebrae
Cranialization and examples
loss of function
vertebrae look like the ones above them
Hox4 loss gives rise to c2-C5 looking like C1
Hox 5 loss makes c3-t2 to look like C2
Hox 10 loss makes Lumbar to look like thoracic vertebrae
Cervical rib
abnormality where there is a rib in the cervical region and contributes to thoracic outlet syndrome
subclavian artery or brachial plexus is compressed usually occurs in the inferior trunk can cause hand issues
Pectus Carinatum
sternum protrusion
Pigeon chest
happens at puberty
Pectus Excavatum
funnel chest
can displace heart
can exercise intolerance
two regions of Myotome
Epimere and hypomere
Epimere
gives rise to epiaxial muscles
innervated by posterior rami
ex: intrinsic muscles on the back
dorsal on the dermomyotome
form extensor muscles and vertebral column
Hypomere
gives rise to hypaxial muscles
gives rise to flexors of the trunks and into the limbs
innervated by ventral rami
ventral on the dermomyotome
cervical myotome
thoracic myotome
lumbar myotome
sacrococcygeal myotome
limb myoblasts
hypomere
Dorsal: posterior compartments extensors and innervated by terminal branches of the posterior cord
Ventral: anterior compartments, flexors and pronators
innervated by the terminal branches of the lateral and medial cords
Poland syndrome
improper migration of the hypoaxial
absence of pectoralis major and minor and sometimes loss of trapezius, serratus anterior, pamaris longus
syndactyly: webbing of fingers
ipsilateral breast hypoplasia
absence of 2 to 4 ribs
Prune belly syndrome
abnormal migration of the hypoaxial muscles and the abnormality migration of the intermediate mesoderm
partial or complete absence of the abdominal musculature
cryptochidism: failure of one or both testes to descend
malformation of the urinary tract and bladder
urethral obstruction
