Wk 3 Limb Embryology Flashcards
Describe relationship between somitomeres, somites, dermomyotomes, dermotomes, myotomes, and sclerotomes
42 pr of somitomeres –> 35 pr somites + 7 pr somitomeres
somites –> dermomyotomes + sclerotomes
Mesenchyme
mesoderm-derived loose embryonic tissue
Intramembranous ossification process
mesenchymal cells differentiate directly into osteoblasts
Bone examples from intramembranous ossification
flat bones of skull (temporal, parietal, frontal)
Endrochondral ossification process
mesenchymal cells differentiate into chondroblasts, lay down hyaline cartilage
Primary ossification centers occur where
diaphysis (shaft of long bones)
Secondary ossification centers occur where
epiphysis, usually occurs post-natally
Epiphyseal plate closes when?
~20 y/o
Achondroplasia
“no cartilage formation” but pathophys is actually failure in ability to convert cartilage to bone, most common form of dwarfism
Acromegaly
excess growth hormone exposure after epiphyseal plates close, large head, hands, and feet
Gigantism
excess growth hormone exposure before epiphyseal plates close
Marfan syndrome
-inheritance
mutation in fibrillin gene –> CT changes resulting in long, thin limbs, CV and resp problems
-autosomal dominant
Osteogenesis imperfecta
extreme bone fragility
Satellite cells (sk. muscle)
in response to injury, can form novel myocytes
Spina bifida (class) pathophys
group of diseases that result from the failure of the neural tube to completely close
incomplete vertebral arch formation
