Electrophysiology
This node as the fastest action potential and serves an important function
Sinoatrial (SA) node. It normally generates and paces the sinus rhythm.
Coronary arteries emerge from:
The coronary arteries emerge from the aorta just after it rises out of the left ventricle
This is unique to cardiac muscle tissue cells
intercalated disks
What triggers action potential in contractile cells?
Pacemaker cell action potential, which is transmitted through intercalated disks.
This represents atrial depolarization
P-wave
This essential cardiac cell type makes up only about 1% of cardiac cells
pacemaker cells
Anatosomes do this thing, and the reason that it is important
collateral circulation, which allows alternate pathways for circulation in the case that a vessel is blocked
These hold muscle cells together
desmosomes
What are the 4 phases of contractile cells?
1-rapid depolarization, 2- initial repolarization, 3- plateau phase, 4- repolarization phase
A blockage along the cardiac conduction system is called, and looks like what on the ECG
Heart block, and looks like extra P-waves and widened QRS complexes.
This cell type has no resting membrane potential (RMP)
pacemaker cells
The three coronary veins are:
The great cardiac vein, small cardiac vein, middle cardiac vein
These allow for rapid communication
Gap junctions, which are electrical synapses
What is important about the refractory period?
It slows heart rate and allows time for the heart to fill with blood
Which type of fibrillation is more life threatening, how is it treated, and what does it look like
Ventricular fibrillation is more life threatening, is treated with defibrillation, and looks like chaotic activity on the ECG
This channel, which allows for a slower depolarization, is triggered to open during what phase of the pacemaker potential.
HCN channels
What is chest pain called?
Angina pectoris
These are types of gated channels that are found in cardiac muscle
sodium ion channels, calcium ion channels, potassium ion channels, nonselective cation channels
This is what calcium ions bind to before these form a crossbridge
Calcium ions bind to troponin, then actin and myosin bind to form a crossbridge
Used to treat dysrhythmias, how would the local anesthetics that block sodium ion channels affect the action potentials of contractile cells
The local anesthetics would interfere with the cell's ability to depolarize and have an action potential.
Which ion allows for phase two of pacemaker action potential, which is called:
Which coronary artery branches off the marginal artery and travels to the posterior side of the heart
posterior interventricular artery
Calcium ion channels are gated how?
voltage gated for opening, time gated for closing
In the process of cardiac muscle contraction, when calcium ions bind to this, this ion is released, and what that does
calcium ions bind to troponin, then more calcium ions are released in "calcium-ion induced calcium ion release," which makes sure there is sufficient calcium ions for contraction.
This is the kind of change that the ECG represents in these cells, not to be confused with this other type of change.
the ECG shows net change in the electrical activity of contractile cells, and does not represent positive and negative differences.