specialised tissues Flashcards
cardiac muscle: explain the structure, physiology and function of cardiac muscle, and compare with skeletal muscle
characteristics and location of cardiomyocytes
“pacemaker cells”, unicellular, present in wall of heart (myocardium), striated
how do intercolated discs connect cardiomyocytes
desmosomes hold membrane structures together, gap junctions allow electrical communication between cells
cardiac vs smooth muscle cells
cardiac cells are larger
method of contraction
same as skeletal muscle
what allows action potential to spread rapidly
Purkinje fibres
shape of action potential compared to heart rate
almost independent
cardiac muscle excitation-contraction coupling
action potential propagates along sarcolemma and down T-tubules → depolarisation opens voltage-gated Ca2+ channels (VGCC) → Ca2+ influx → Ca2+ induced Ca2+ release (CICR) by binding to RyR on SR/initiate contraction through troponin binding/further depolarisation → increase in IC Ca2+ → muscle contraction
