electrical heart <3
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the flattened superior portion of the heart
base of the heart
great vessels of the heart are what and where are they located?
vena cava, aorta, pulmonary trunk base of the heart
inferior tip directed downward and to the left
apex
auricle
ear shaped flap of atria
goal of heart valves
unidrectional blood flow
Atrioventricular (AV) valves what is between right atrium and right ventricle
tricuspid valve
Atrioventricular (AV) valves what is between left atrium and left ventricle
bicuspid/mitral valve
what are the semilunar valves
aortic valve and pulmonary valve, between the ventricles and their corresponding artery
path of blood flow
right atrium –> ventricle –> pulmonary trunk –> lungs –> pulmonary veins –> left atrium –> left ventricle –> aorta –> body –> returns to heart via vena cava
layers of the heart wall from inner most to outer most
endocardium (lining on inside), myocardium (heart wall itself, has the cardiomyocytes), epicardium (visceral pericardium on the heart), parietal pericardium (faces cavity where heart sits)
cardiac muscle cells are called __ and the two types are __
cardiomyocytes conductile and contractile cells
cardiac muscle cells are [3 things]
• straiated • branched at ends • large/numerous mitochondria
3 differences among heart and skeletal muscle cells
• heart - shorter and thinner than skeletal (50-100 uM long, 20 uM diameter) • heart - mononucleated (skeletal multinucleated) • heart - reduced SR system, extensive T tubule system
unique feature of cardiomyocytes are intercalated discs which are made up of what
desmosomes: mechanical coupling gap junctions: electrical coupling
what are desmosomes
tight junctions between cells so all the contractions happen at the same time, mechanical coupling
what are gap junctions
proteins that create channel from cell 1 to cell 2 allowing ions to flow, electrical coupling
the majority of cells in the heart
contractile cells, bulk of atrial and ventricular tissue contraction and transfer of electrical signals via gap junctions
which cells generate and propogate electrical activity
conductile cells`
Differences in skeletal muscle vs cardiac muscle (nervous system, source of rise in Ca, removal of Ca)
• skeletal – innervated by somatic nervous system, cardiac – influenced by autonomic nervous system • skeletal – Ca from SR, cardiac – Ca from SR and ECF • removal of Ca - same as 2
what are the 6 general events of cardiac contraction
• blood returning to heart pours into ventricles (AV valves open, semilunar valves close) • atria contract first to “top off” filling of ventricles • ventricles contract, AV valves close • pressure builds in ventricles • semilunar valves open • blood ejected
electrical signals triggers myocyte contraction and then ____
conduction system spreads electrical signal in highly organized pattern/sequence
pathway of wave of electrical excitation (conductile pathway comprised of conductile cells) what are the 6 steps
• SA node (normal pacemaker) • atrial internodal fibers (atrial contraction) • AV node (slowed transmission of impulse) • AV bundle (bundle of His) • Right and left bundle branches • Purkinje Fibers (rapid propagation)
right ventricle pumps blood to ___ and left ventricle pumps blood to ____
right - lungs left - rest of body
what is the normal pacemaker of the heart and what does automaticity mean
SA node automaticity: fires electrical signals on its own