Two important minerals that the body needs for heart contractions are sodium (Na+) and potassium (K+). These two minerals are most often used as electrolytes within the body, and because of this, the body is able to use them as energy sources because of the electric potential. According to Johnathon Andrew, electric potentials in the body are created by any changes in electrolyte concentrations within cardiac cells. These electric potentials can then be used as a source of energy that can be used to relay messages to the brain that allow for heart contractions to occur. In addition, Howard Glicksman discusses how important the concentration of potassium is to an individual’s heart. In the article he talks about how inside of a cell’s plasma membrane, it carries a negative electric charge, while on the outside of the cell’s plasma membrane, it carries a positive charge. This difference in electric potential allows for cells to be excitable, so that that can depolarize the membrane, and then reverse the charges of the membrane potential. When this happens, the inside of the membrane becomes a positive charge, whereas the outside has a negative one. The reason these Na+/K+ pumps are important to our everyday lives is because these pumps provide our cardiac cells with the necessary energy to contract. If our cardiac cells did not have the proper electric potential within them, then our heart would undergo irregular contractions (heartbeats) which can be very dangerous to an individual’s health. Although this concept may sound very straight-forward, it is anything but simple. Through the use of an enzyme known as Na+/K+-ATPase, cells are able to regulate the concentration of potassium, and sodium within the cell. In order to keep this concentration in its resting potential, the cell exports three sodium ions through these pumps, and imports two potassium ions into the membrane. Wikipedia discusses the nature of this enzyme and the role it plays within cells. It states, that the nature of this transport is active transport, and the reason for this is because both ions (sodium and potassium) are going against the concentration gradient, therefore it requires energy to be transported in a way that is unfavorable in terms of concentration gradient. This relates to our lectures because it a direct example of electric potential. In our lecture slides, it talks about how electric potential is calculated by the scalar sum of potentials of all charges within the system. How this relates to the Na+/K+ pump, is because sodium ions, as well as potassium ions are regulated through channels, whenever equilibrium is not met (whether inside or outside of the plasma membrane). These ion pumps could also be compared to current. The reason these two different concepts could be compared is because they follow very similar paths. Electrons move against the current, likewise sodium and potassium ions both go against their concentration gradient. Although these concepts are very different in every other aspect, both of these molecules follow similar paths of movement, and you can see this because they both go ‘against the grain’. The movement of these molecules is about the only thing these two concepts have in common. Because when you look into the nature of protons and electrons, protons have no movement, whereas electrons have movement (if excited). One thing in particular that confuses me about the Na+/K+ pump, is why the cell wants more potassium inside its membrane than it does sodium. Both ions have a +1 charge, so it makes me wonder what potassium can offer to the cell, that sodium cannot? ?
Andrew, Johnathon. “Are Potassium & Sodium Related to the Heart’s Contraction?” Healthy Eating | SF Gate, 11 June 2018, healtheating.efgate.com/potassium-sodium-related-hearts-contraction-9102.html.com
“Cardiovascular Function: The Heart Follows the Rules.” Evolution News, 9 July 2015, evolutionnews.org/2015/07/how_the_heart_f/.
“Na/L-ATPase.” Wikipedia, Wikimedia Foundation, 5 Sept. 2018, wn.wikipedia.org/wiki/Na/K-ATPase