AG ch-1

Pericardium is protective barrier around heart. Consider standing in a small closet, u begin to blow up a balloon, eventually balloon will stick to closet wall=parietal pericardium and also ballon will come back and stick to u=visceral pericardium. The intermitent space is filled with lubricants . If blood due to trauma or injury occurs in this space, heart has no place to expand=life threatening. Pericarditis=inflammation w/c may affect heart moving properly. Heart has 4 chambers, 2 atria, atrium=waiting room and 2 ventricles. Path= LV-> systemic-> rt atrium-rt venticle->lung-> left atrium-> LV. Valves are mitral, aortic tricuspid and pulmonary. Left side of heart is four times as thick b/c must pump throughout body while rt side just pumps to lungs. Aorta is vessel w/c comes off LV. Comes back and gives blood to heart via the rt and left coronary artery. Blockages=> infarction. Lots of hollow structures are joined= anastomosis=redundancy. Sinoatrial node is the primary pacemaker. Current spreads to the av node down through bundle of his to the purkinje fibres. If atrial fibrillates, cardiac out decreases to 70%. Can lead to clots. Heart has a natural rhythm. If infarction occurs on eletrical conduit ie sa node ->av node-> bundle of his->purkinje fibres. heart is autorhythmic hence will beat but at a faster rate and will be less efficient due to less co-operation from other parts of heart.