I
II
III
IV
V
100

for action potentials in contractile cells, phase 1 depolarization occurs due to influx of ______

Na+

100

What are the 2 ways to remove calcium from the cytosol?

1. SERCA pump back into SR

2. Na+/Ca2+ exchanger puts calcium back to ECF

100

What are the 3 stages of ventricular diastole?

1. early diastole

2. late diastole

3. atrial systole

100

After ventricular diastole there is ventricular systole. At the end of ventricular systole the end systolic volume (ESV) is _____ mL while the stroke volume is ________ (mL)

80 mL; 70 mL

100

The QRS complex corresponds to _____________ (include electrical and mechanical events)

ventricular depolarization and ventricular systole

200

phase 2 early repolarization/plateua is caused by a closing of ____ channels and a slow influx of _______

close Na+ channels; slow influx of Ca2+

200

T or F: the SA node has autonomic regulation from only the sympathetic nervous system

False. The SA node has both sympathetic and parasympathetic regulation

200

During isovolumetric relaxation, AV valves are (open or closed) and semilunar valves are (open or closed) 

closed; closed. Isovolumetric means 'same volume', so the ventricles will have the same volume of blood--this is only possible when both valves are closed and there is no blood entering or leaving the ventricles.

200

During the 1st phase of ventricular systole, _______ valves close and the ventricles exhibit isovolumetric contraction, resulting in an (increase or decrease) in pressure

AV valves; increase

200

The T wave corresponds to ______________

ventricular repolarization (leads to ventricular diastole)

300

during phase 3 repolarization, _____ channels close and ______ channels open

Ca2+ close; K+ open --> efflux of K+

300

a negative chronotropic effect refers to a _____________ in heart rate (inc or dec)

decrease in heart rate

300

The ventricles are "topped off" with blood during ___________

atrial systole

300

What happens when the ventricular pressure exceeds aortic pressure?

semilunar valves open

300

cardiac output = _____ x _______

HR x SV

400

calcium required for contraction comes from 2 places: 

1.

2.

1. ECF (20% of Ca2+)

2. SR (80%)

400

Sympathetic regulation of the SA node results in a(n) ____________ in heart rate and is therefore a ___________ chronotropic effect

increase; positive

400

The end diastolic volume (EDV) is ___ mL

150 mL of blood in the ventricles 

400

The S1 lubb sound corresponds to closure of the _____ valves, while the S2 dubb sound is closure of the ______ valves

AV; semilunar

400

what influences contractility (and therefore influences ESV and stroke volume)?

levels of cytosolic calcium

500

calcium entering the myocyte through the L-type (slow) Ca channels binds to _________ receptors on the SR to stimulate SR calcium release

ryanodine receptors

500
Fill the blanks with either relaxation or contraction: systole refers to _________ while diastole refers to _____________ of the heart

contraction; relaxation

500

During late diastole the AV valves open because the pressure in the ventricles (increases or decreases) relative to the atria

decreases

500

The P wave corresponds to _____________ (include electrical and mechanical events)

atrial depolarization and atrial systole

500

Starling's principle of the heart says that a higher preload leads to a (higher or lower) stroke volume

higher stroke volume