Cardiac Muscle and Heart Function. Cardiac muscle fibers are striated – sarcomere is the functional unit Fibers are branched; connect to one another at intercalated discs . The discs contain several gap junctions Nuclei are centrally located Abundant mitochondria
ALL CONDUCTION FIBERS CONNECTED TO MUSCLE FIBERS THROUGH GAP JUNCTIONS IN THE INTERCALATED DISCS
Why are fibers of the conducting system systemautorhythmic?
How does the depolarization in these cells affect cardiac muscle cells?
Superimpose changes in the muscle cell’s membrane potential on this graph
Membrane potential of SA nodal cells
Changes in ion concentrations in a cardiac muscle fiber following depolarization
What causes the muscle resting membrane potential to change initially?
What would be happening with a skeletal muscle at this point?
How do these neurotransmitters get these results?
1 depolarization of pacemaker
ECG examines how depolarization events occur in the heart depolarization of pacemaker
Arhythmias can be detected with an ECG exactly parallel to the axis of lead II (which is from RA to LL), a positive deflection (P wave) would result in that lead.draw the others
Compounds that increase or decrease rate are called chronotropic agents
Compounts that increase or decrease force of contraction are called inotropic agents
Cardiac Cycle exactly parallel to the axis of lead II (which is from RA to LL), a positive deflection (P wave) would result in that lead.
100 exactly parallel to the axis of lead II (which is from RA to LL), a positive deflection (P wave) would result in that lead.
What would I have to know to be able to determine what the cardiac output is at rest?
What is the stroke volume?
What determines the stroke volume?
How can I alter cardiac output?
What causes this increase in stroke volume? each minute