Cardiac pacemaker and eventual action potential in contractile cells. Having cardiomyocytes connected via gap junctions allow all contractile cells of the heart to act in a coordinated fashion and contract as a unit. All the while being in sync with the pacemaker cells; this is the property that allows the pacemaker cells to control contraction in all other cardiomyocytes. Cells in the SA node spontaneously depolarize, ultimately resulting in contraction, approximately 100 times per minute. This native rate is constantly modified by the activity of sympathetic and parasympathetic nerve fibers via the autonomic nervous system, so that the average resting cardiac rate
Cardiac output a function of the rate of blood flow and the rate of oxygen picked up by the red blood cells. Application of the Fick principle involves calculating the oxygen consumed over time by measuring the oxygen concentration of venous blood and arterial blood. "Q" is calculated from these measurements as follows: From these values, we know that: formula_20 where This allows us to say Cardiac output Cardiac output (CO, also denoted by the symbols formula_1 and formula_2), is a term used in cardiac physiology that describes the volume of blood being pumped by the heart, in particular by the left