Cell signaling of adjacent cells. In cardiac muscle, gap junctions between adjacent cells allows for action potential propagation from the cardiac pacemaker region of the heart to spread and coordinately cause contraction of the heart. The notch signaling mechanism is an example of juxtacrine signaling (also known as contact-dependent signaling) in which two adjacent cells must make physical contact in order to communicate. This requirement for direct contact allows for very precise control of cell differentiation during embryonic development. In the worm "Caenorhabditis elegans", two cells of the developing gonad each have an equal chance of terminally differentiating or becoming a uterine
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