Electrical Axis of the Heart

1			The electrocardiogram (ECG) measures:
			A)	contractions of the atria and the ventricles.
			B)	the electrical activity of the pacemaker cells.
			C)	action potentials in the atria and the ventricles.
			D)	the heart sounds.
2			The QRS wave coincides with:
			A)	depolarization of the atria.
			B)	depolarization of the ventricles.
			C)	depolarization of both the atria and the ventricles.
3			Look at your graph. What is the angle of the heart?
			A)	About 0 degrees.
			B)	About 40 degrees.
			C)	About 65 degrees.
			D)	About 90 degrees.
4			Does the axis of the heart (a line running from between the atria to the tip of the ventricles) point:
			A)	out through the left side of the body.
			B)	out through the right side of the body.
			C)	horizontally.
			D)	vertically.
5			What conditions can change the angle of the heart?
			A)	Exercise.
			B)	The late stages of pregnancy.
			C)	Slow breathing.
			D)	An increase in blood pressure.