Notes in Limb Development

To Subscribe, use this Key

Status	Last Update	Fields
Published	09/07/2023	Limb development starts at week {{c1::4}}
Published	09/07/2023	Limbs develop (mostly) from {{c1::paraxial (somitic)}} and {{c2::lateral plate mesoderm}}
Published	09/07/2023	Dermal connective tissue derived from dermatome and limb muscles derived from ventrolateral (abaxial) myotome come from {{c1::somites}}
Published	09/07/2023	Bones, blood vessels, and associated connective tissue are derived from {{c1::lateral plate mesoderm.}}
Published	09/07/2023	Melanocytes in epidermis, Schwann cells in nerves and sense organs are derived from {{c1::neural crest.}}
Published	09/07/2023	Does the forelimb bud or hindlimb bud begin to protude first?
Published	09/07/2023	Limb buds consist of {{c1::a core of mesenchyme}} and an {{c1::outer covering of ectoderm.}}
Published	09/07/2023	The limb buds begin as protrusions from the {{c1::lateral plate mesoderm}}.
Published	09/07/2023	Joints form at regions of {{c1::arrested chondrogenesis}} by {{c2::cell death}}.
Published	09/07/2023	While external shape is being established, the {{c2::mesenchyme}} begins condensing and chondrocyte differentiation ensues. The first cartilage models…
Published	09/07/2023	What is the first step of endochondral bone formation in the limbs? {{c1::Mesenchyme from lateral plate mesoderm condenses into chondrocytes}}
Published	09/07/2023	What is the second step of endochondral bone formation in the limbs?{{c1::Chondrocytes form a model of the prospective bone}}
Published	09/07/2023	What is the third step of endocondral bone formation in the limbs?{{c1::Blood vessels invade the center of the model, where osteoblasts localize, and …
Published	09/07/2023	What is the fourth and last step of endocondral bone formation in the limbs?{{c1::Chondrocytes toward the shaft (diaphysis) undergo hypertrophy and ap…
Published	09/07/2023	Growth of the long bones continues into early adulthood and is maintained by what?{{c1::proliferation of chondrocytes in the growth plates }}
Published	09/07/2023	At {{c1::6 weeks}}, the terminal portion of the limb buds flatten to form {{c2::hand- and footplates}}.
Published	09/07/2023	Fingers and toes (digits) are formed when {{c1::cell death}} in the {{c2::AER}} separates the plate into five parts.
Published	09/07/2023	Limb patterning and growth is genetically regulated by what?{{c1::Hox genes, FGF, Shh, and FGF}}
Published	09/07/2023	Bone “identity” is regulated by what? {{c1::HOX genes}}
Published	09/07/2023	Embryonic spatial nomenclature: cranial = {{c1::toward the head}}
Published	09/07/2023	Embryonic spatial nomenclature: rostral = {{c1::toward the nose}}
Published	09/07/2023	Embryonic spatial nomenclature: caudal = {{c1::toward the tail}}
Published	09/07/2023	Embryonic spatial nomenclature: dorsal = {{c1::toward the back}}
Published	09/07/2023	Embryonic spatial nomenclature: ventral = {{c1::toward the belly}}
Published	09/07/2023	Embryologists will often use {{c1::anterior}} instead of cranial
Published	09/07/2023	Embryologists will often use {{c1::posterior}} instead of caudal
Published	09/07/2023	What is amelia?
Published	09/07/2023	What is meromelia?
Published	09/07/2023	What is Phocomelia?
Published	09/07/2023	What is Adactyly?
Published	09/07/2023	What is Ectrodactyly?
Published	09/07/2023	What is Polydactyly?
Published	09/07/2023	What is Syndactyly?
Published	09/07/2023	At the tip of the limb bud a signaling structure, the {{c1::apical ectodermal ridge (AER)}} forms and signals {{c2::mesenchyme to proliferate and the …
Published	09/07/2023	Removal of the AER inhibits what?{{c1::outgrowth of the limb}}
Published	09/07/2023	Transplantation of a second AER duplicates the limb and is called what?{{c1::diplopodia}}
Published	09/07/2023	Removal of the AER at early stages causes {{c1::severe truncations}} of the limb skeletal elements.
Published	09/07/2023	Removal of what arrests limb development at stage at which it was removed?{{c1::AER}}
Published	09/07/2023	What are two causes of amelia?
Published	09/07/2023	Forelimb-Hindlimb Identity: the ectoderm (AER) promotes outgrowth, but {{c1::mesoderm}} controls limb identity.
Published	09/07/2023	The {{c3::Zone of Polarizing}} activity establishes {{c1::POSTERIOR (caudal)}} identity (duplication results in a {{c2::mirror image}})
Published	09/07/2023	Factors secreted by {{c2::ZPA}} indirectly induce {{c1::proliferation of the AER}}
Published	09/07/2023	Loss of the ZPA will affect {{c1::A-P pattern}} and cause {{c2::shortened limbs}}
Published	09/07/2023	Digit identity is patterned by {{c1::Shh}}
Published	09/07/2023	Formation of digits requires a balance between {{c1::cell proliferation}} at digit tips and{{c1::cell death}} in interdigital regions.
Published	09/07/2023	{{c1::Syndactyly}} is the fusion of fingers and toes due to inadequate cell death between digital rays.
Published	09/07/2023	{{c1::Polydactyly}} is the duplication of digits (very often posterior)
Published	09/07/2023	The {{c1::Hox code}} is used for proximo-distal patterning of the limbs.
Published	09/07/2023	The maturation of limb elements sequence is {{c1::proximo-distal (e.g. humerus before radius)}} and {{c2::postero-anterior (e.g. ulna before radi…
Published	09/07/2023	Phocomelia (partial loss of limb) is caused by what three things? {{c1::FGF disruption, HOX disruption, and angiogenesis disruption. }}
Published	09/07/2023	Forelimbs rotate {{c1::90 degrees}} inward, and hindlimbs rotate {{c1::180 degrees}} inward.
Published	09/07/2023	Primaxial myotome (dorsomedial portion closest to neural tube) cells are generally less {{c3::migratory}} and therefore contribute to {{c2::epaxial mu…
Published	09/07/2023	Abaxial myotome (ventrolateral portion closer to lateral plate mesoderm) cells are {{c1::more}} migratory and therefore go into {{c2::limbs and ventra…
Published	09/07/2023	The innervation of the adult muscle reflects the segment from which is was {{c1::derived}}.
Published	09/07/2023	{{c1::Poland Syndrome}} is the absence/reduction of pectoralis minor/major muscles.
Published	09/07/2023	{{c1::Prune belly syndrome}} is the atrophy or lack of abdominal wall musculature
Published	09/07/2023	{{c1::Congenital joint contracture}} is observed with in utero denervation or atrophy of muscle (suggests that proper joint/skeleton development …
Status	Last Update	Fields