DASC20010 Lecture Notes - Lecture 15: Sinoatrial Node, Cardiac Muscle, Desmosome

• School: University of Melbourne
• Department: Animal Science
• Course: DASC20010
• Professor: Peter Cakebread

Document Summary

Things can pass between via desmosomes and gap junctions keep connections between membranes tight. Sinoatrial node- in right atrium, most sensitive, depolarises then spreads the action potential. Atrioventricular node- after atria contract this passes it to the bundle. Purkinje fibres- myofibrils depolarise in the cardiac muscle and contract the ventricles. When ca gets to a maximum the gate closes and k channel opens and it leaks out to bring. In other cells (not sinoatrial node) na opens then closes and ca opens and then closes and k opens. Refra(cid:272)tory period duri(cid:374)g the 250 (cid:373)se(cid:272) (cid:271)e(cid:272)ause (cid:272)a(cid:374)"t ha(cid:448)e 2 ap at sa(cid:373)e ti(cid:373)e. Repolarisation of atria happens simultaneously with qrs so ca(cid:374)"t (cid:271)e see(cid:374) (cid:894)t is just of (cid:448)e(cid:374)tri(cid:272)les(cid:895) Atrial/ventricular fibrillation- atria just quivers, p looks similar to qrs. Systole- pumping out of heart: av valve closed, contraction of atria and ventricles, pulmonary and aortic valves open. Diastole- blood into heart: pulmonary aortic valves close, ventricles fill.