Devo Flashcards
How are cells arranged in embryonic ct?
they are mesenchymal and scattered either as individual cell or into aggregates of cells
What does STFM develop from in the trun?
Scleratome, somatic mesoderm
What does STFM develop from in the head?
neural crest and head mesoderm
What is differentiaation of preskeletal mesenhcyme mediated by?
cartilage–> Sox-9
Bone- Runx-2
What does Sox-9 drive STFM cells to differentiate to?
chondroblasts
What will perichondrium develop around?
hyaline and elastic cartilage
How do most bones form?
Endochondral ossification
What is the diaphysis of the bone?
the shaft
What are secondary ossification centers?
additional centers of bone formation appearing in the prenatal postnatal or postpubertal period
What is chondrodystrophias?
hterogenous group of disorders characterized by disproportionate growth.
What is acodroplasia?
common cause of dwarfism due to interference with epiphyseal plate; associated with mutation of fibroblast growth factor receptor 3
What mutation is associated with achondroplasia?
Fibroblast growth factor receptor 3
What is the defect associated with marfan syndrome?
fibrillin
What is mucopolysaccharidoses disorder?
family of metabolic diseases that result in dwarfism
What is hyperpituitarism caused by?
overproduction of growht horomone; can result in gigantism or acromegaly
What is hhypothyroidism characterized?
pituitary dwarf; mental retardation and skeletal and ear anomolalise
What do cells in the dermomyotome become?
precurosors to skeletal muscle and fibrous connective tissue
What ar ehte first 4-5 somites reffered to as?
occipital somites
What does the central scleratome compartment form?
pedicle and proximal rib
What does the ventral part of the scleratome rib form?
vetebral body, intravetebral disc
What does the dorsal part o the scleratome compartment form?
dorsal part of neural arch, spinous process
What does the lateral scleratome compartment form?
distal rib
What does the somitocoel cells form?
vetebral joints, intravetebral disc, proximal ribs
What does the syndetome do?
form tendons for the intrinsic back muscles
What is a klippel-feil sequence?
aka brevicollis; recessive disorder characteriezd by presence of fused cervical vertebrae
Whaat is sacralized and lumbarized vertebrae?
sacralization; fifth vertebrae incorporated into sacrum
or lumbarization is the opposite, 1st sacraal vertebrae not included
What iss dysraphism?
failure of fusion of neural arches
Where is teh sternal primordia dervied from?
somatic mesoderm
What is all skeletal muscle derived from?
paraxial msoderm
Where do muscles of body wall and limbs form from?
somites
Where do cardiac and visceral smooth muscle origginate from?
Splanchnic mesoderm
Where does vascular smooth muscle originate from?
local mesenchyme
Where does the smooth muscle of the constrictor and dilator papillae muscle annd myoepithelial cells of ammary gland and sweat gland originate from?
ectoderm
Myogenic regulatory factors form what?
intrinsic muscles of the back as well as the prevetebral and intercostal muscles
What is the primaxial domain?
where prevetebral and intercostal musclesattach to bones
What is the abaxial domain?
muscles of the abdominal wall and the limbs and the infrahyoid muscles
Once cells become part of the myotome protion of hte DM their lineage is restricted to waht?
skeletal muscle lineage; these are called myogenic cells or pre-myobasts
What do myoblasts fuse with each other to form what?
multinucleated myotubes, a process that requires expression of M-cadherin
In myotubes, troponing and topomyosin mediate myofiber and sacromere formation resulting in what?
differentiated mucle cell or muscle fiber
Postnatal growth of skeletal muscle is accomplished by myogenic stem cells called what?
Satellite cells
What are the muscles in head and neck derived from? And innervated by what?
head mesoderm and cranial nerves
The myotome is dived into what?
epaxial dorsal portions (ventral primary rami) and ventral hypaxial portions (dorsal primary rami)
What is the difference between primaxial and abaxial versus epaxial and hypaxial
the first refers to embryonic development location the second referst ot innervation
What are the two transcription factors associated with smooth muscle gene expression?
myocardin and serum response factor
What is poland sequence?
absence of pectoralis major and pectoralis minor muscle as a result nipple is displaced
What is prune belly syndrome?
1) absence of abdominal muscles
2) undescended testicles
3) bladder and urinary tract anomalies
What is congenital muscular torticollis?
characterized by a fixed rotation and tilting of head to one side. Also have hip dysplasia. occur in absence or trauma with SCM muscle
What is the beckers type of Muscular dystrophy?
later onset and a milder condition than Duchennes
What is pahse 1 of limb development? When is it?
early week 4; establishment of a limb field; somatic mesoderm located on each side of embryo; regulated by hox genes
What is phase 2 of limb development? When is it?
during week 4, budding;
Limb buds; of somatic mesoderm, neural crest and spinal nerves. Surface forms thickend ridge called apical ectodermal ridge
What is phase 3 of limb development?
Week 5-week 8; elongation of limb and limb rotation
What is phase 4 of limb development?
begins week 5; tissue formation and organization
What is failure of formation of limb parts?
birth defects where all or part of limb is missing
- transverse type is an amputation
- longitudal type is an absence of structures along the medial access
What is oligodactyly?
lobster claw deformity
What is phocomelia?
seal limb; distal segment is attached to proximal segment common in thaladomide babies
What is syndactyly?
fusion of one or more digits
What is sirenomelia?
more severe version of syndactyly
What is polydactyly?
duplication of digit
What is club foot/
foot ankle defect involving talas bone; talipes equinovarus most common type,
What is developmental dysplasia of hip?
condition where hip is easily dislocated sually after birth
What is cleidocranial dysplasia?
hypoplasia or aplasia of clavicles
What is sprengal deformity?
undescended scapula, dysplastic
