be230cLecture7

Bundle and branches working automalcity high

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Unformatted text preview: regionalized cell differenLaLon to provide highly specialized funcLonality •  AddiLonal cardiac Lssue will be added over next few weeks of development TRUNCUS ARTERIOSUS BULBUS CORDIS PRIMITIVE VENTRICLE PRIMITIVE ATRIUM SINUS VENOSUS Cardiac Looping and Chamber FormaLon ­ 1 3 4/23/13 Basic features of cardiac muscle cells Type of Myocardium Characteris:c Primary Nodal Bundle and branches Working AutomaLcity High High High Low ConducLon Velocity Low Low High High ContracLlity Low Low Low High SR AcLvity Low Low Low High Cardiac Looping and Chamber FormaLon ­ 2 Situs Inversus 4 4/23/13 Heterotaxia LR Asymmetry DeterminaLon Cascade •  •  •  •  Core components of led ­right asymmetry determinaLon cascade shown Culminates in expression of transcripLon factor Pitx2 on led side of heart tube Dictates direcLon of heart tube rotaLon, atrial paeern, and aorLc arch remodeling Genes implicated in human heterotaxy include genes that encode proteins in primary cilia (e.g. DNAI1 and DNAH5, both of which code for proteins found in the ciliary outer dynein arm) and ZIC3, LEFTYA, CRYPTIC, and ACVR2B (which encode proteins involved in transducing the LR informaLon to the heart) child with dextrocardia Cilia in the Node Control UnidirecLonal Fluid Flow that is...
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This document was uploaded on 04/09/2014.

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