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1. SISTEMA MUSCULAR
Deriva:
 Capa germinal mesodérmica (Excepto algunos tej del M. Liso)
 Esquelético:
o Mesodermo paraxial
 Somitas (Región occipital-sacra)
 Somitomeros (Cabeza)
 Liso:
o Mesodermo visceral:
 Rodea al intestino y derivados
o Ectodermo:
 Músculos pupilares y de glándulas mamarias y sudoríparas.
o Cresta neural y mesodermo de la placa lateral.
 Musculo de Aorta dorsal y grandes arterias.
o Células proepicardicas:
 Musculo de A coronarias.
 Cardiaco:
o Mesodermo visceral
 Circunda tubo cardiaco.
MUSCULATURA ESQUELETICA ESTRIADA
Musculatura deriva:
 Cabeza:
o 7 somitomeros
 Esqueleto axial y extremidades
o Somitas
 Región ventral: Esclerotoma
 Región superior:
 Dermatoma
 2 regiones formadoras de musculo en:
o LVL (Labios ventrolaterales)
 Células migran a la capa parietal adyacente del mesodermo de la
placa latera y forman músculos:
 Infrahioideos
 De la pared abdominal
 De las extremidades
 Células que permanecen en el miotoma:
 De la espalda
 De la cintura escapular
 Intercostales
o LDM (Labios dorsomediales)
 Las células de ambos migran ventral al dermatoma y forman el dermomiotoma.
 Frontera somítica lateral:
o Límite entre dermis que deriva de los dermatomas y del mesodermo de la placa lateral
o Límite entre somitas y capa parietal del mesodermo de la placa lateral.
 Separa 2 dominios:
 Primaxial:
o Mesodermo paraxial.

2. o Circunda al tubo neural.
o Células musculares primaxiales
 Abaxial:
o Capa parietal del mesodermo de la placa lateral.
o Células musculares abaxiales
o Limite para el desarrollo de costillas:
 Óseo: Primaxial
 Cartilaginoso: Abaxial
 Cada miotoma esta inervado por N. raquídeos derivados del mismo segmento que las cels musculares
INERVACION DE LOS MUSCULOS DEL ESQUELETO AXIAL
 Epimericos o epaxiales (Músculos de la espalda):
o Ramas 1rias dorsales
 Hipomericos o hipaxiales (De las extremidades y pared del cuerpo)
o Ramas 1rias ventrales
TENDONES
 Derivan: Esclerotoma
 SCLERAXIS: Regula el desarrollo
MUSCULOS ESQUELETICO
 Mioblastos se fusionan y forman fibras musculares
 Luego aparecen miofibrillas
 Al final del 3er mes se ven estriaciones
REGULACION MOLECULAR DEL DESARROLLO MUSCULAR
 BMP4 + WNT: Emiten señales para que células de LVL expresen el Gen MyoD.
 BMP4: Síntesis de WNT
 WNT + SHH: Inducen la expresión de genes MYF5 y MyoD por células de LDM.
 MYF5 + MyoD: Codifican factores reguladores miogénicos
o Activan vidas para el desarrollo muscular.
DESARROLLO DE PATRONES MUSCULARES
 Patrones son controlados por el tej conectivo al cual migran los mioblastos.
 Tej deriva:
o Cabeza: Cresta neural
o Región cervical y occipital: Mesodermo somítico
o Extremidades y pared corporal: Capa parietal del mesodermo de la placa lateral
MUSCULATURA DE LA CABEZA
 Todos los voluntarios derivan del: Mesodermo paraxial
 Expecto la musculatura del iris: Ectodermo de la capa óptica.
MUSCULATURA DE LAS EXTREMIDADES
 7ma semana: 1ros indicios por condensación del mesénquima cerca de las bases de las yemas.
MUSCULO CARDIACO
 Mioblastos forman uniones especiales: discos intercalares.
 Fibras de Purkinje: Haces especiales de células musculares con miofibrillas irregulares

3. MUSCULO LISO
 Factor de respuesta sérico (SRF): Responsable de la diferenciación de células de musculo liso.
 Miocardina +factores de transcripción relacionados con la miocárdina (MRTF): Coactivan SRF.
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