ANHB1102 Lecture Notes - Lecture 13: Heart Valve, Endocardial Tubes, Atrioventricular Node
4 Dec 2018
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Must be functional for nutrients and oxygen (diffusion no longer viable at wk4). Cv system are mesoderm derivatives (as do muscles). Cardiogenic area has blood islands (early blood vessels) at cranial end w endocardial tubes on either side. Tubular heart (early) then starts to bend and early atria and ventricles move to positions where they will sit in adult heart (correct positioning) (looping) Lungs aren"t functional so blood moves direct between atria. Folding of embryo puts heart bulge into the correct position (moves caudally so it sits below oral membrane or mouth). Muscle cells = cardiocytes - short branching cells (for many connections), striated, single+central nucleus. contract on their own (regulated by nerve cells). Intercalated discs - connect adjacent cells (ie. sit at cell junctions), mechanical strength, electrical communication = allows cells to function as one unit. K+ and ca2+ exits for re-polarisation (through k+ channels) Av node (signal from atria to ventricles. near right.
