The ventricles of the heart connected so intimately to each other in driving the function of the whole heart were therefore thought to have very similar function. Moreover, the proteins of LV and RV originate from the same genes (Myl6 for ELC, MYH6 and MYH7 for HC, MYL2 for RLC, MYL3 for LC). Only, recent advances shed light on their dissimilarities at varying levels of genetic, proteomic 5, force studies etc 14, 24,38.
Much of the differences in the LV and RV are explicable from their different embryological origins and partly by the RV exposure to lower post-partum cumbrance 4,35. Previously, the myocardium was thought to originate from single source of myocardial progenitor cells, however, recent study’s recognition of two different
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Investigations performed at the gene level delineate differences in the mRNA and miRNA protein gene expressions between the two ventricles, with higher levels of expression concentrated in LV 11. Other reports suggest differences at the protein levels of the two ventricles wherein higher amounts of energy using proteins like ATP synthase and others like Heat Shock Protein (HSP), Myosin Binding Protein C (MBPC) and Myosin Light Chain 2 (MLC2) were noted in Left compared to the Right ventricles in healthy mice hearts 5, 24, 38.
The dichotomy of LV and RV are also expressed at their physiological levels. The LV and RV although, linked intimately, also show differences at their basic fiber structures. The RV consists of transverse fibers in its free wall with shared oblique fibers in its interventricular septum while the LV is encircled by oblique and circumferential fibers 51. It is known that the oblique septal fibers and circumferential LV fibers are more mechanically efficient than the transverse fibers of RV in an event of an afterload 1,50. Although, differences have been noted at many levels, differences at the functional levels remain yet elusive.
Heart Failure: The prevailing ignored subtle differences, in part or combination, may lead towards developing the two different forms of heart failures these ventricles undergo. While 5.1 million people in the USA have been diagnosed with heart failure so far, heart failure
Early doctors were researching arrhythmia in heart beat as a result of unknown abnormal neuro-cardio mechanisms of the heart, one of theories was that SA and AV nodes were interfering with each other’s bio-electrical impulses another theory was that the right side of the septum was hypersensitive to electrical impulse, all were more else on the right track because we know now that SVT is a result of a faulty electrical connections of the heart.
Heart failure can be attributed to either right sided, left or both. Left-sided heart failure is of two types, systolic failure and diastolic failure. Systolic failure is the when the left ventricle loses its ability to contract normally. The heart cannot pump with enough force to push enough blood into circulation. Diastolic failure is when the left ventricle loses its ability to relax normally. Which results in the heart not being able to fill with blood during the resting period. Both result in a decrease in cardiac output. (AHA, 2012). A decrease in the cardiac output into the systemic circulation causes blood to accumulate in the left ventricle, left atrium, and pulmonary circulation. This increase
Based on the external observation, the left side of the heart appeared bigger than the right side. When looking at the heart internally, the right ventricle pumps the blood to the lungs, and the left ventricle to the rest of the body. Therefore the left ventricle needs to be stronger and bigger, than the right ventricle, as it has a larger role in the functioning the heart.
1. The pulmonary circuit is supplied by which ‘side” of the heart? The systemic circuit? The right atrium
How does the structure of cardiac myocytes and intercalated disks follow the function of cardiac muscle tissue
R E V I E W S H E E T 30 Anatomy of the Heart
Heart failure, HF, is a result of one’s heart inefficiently pumping blood out to the body (Lewis, Dirksen, Heitkemper and Bucher, 2014, p.766). A healthy heart will pump blood out of the left and right ventricles rhythmically and simultaneously, creating an even flow of blood from the heart to the pulmonary arteries and the aorta (Lewis et al., 2014, p.769). Someone with heart failure has a ventricular dysfunction in either one or both ventricles; the ventricles are not filling or contracting properly. The failure of one ventricle to properly function leads to an overcompensation of the opposite ventricle as well as a disruption in normal blood flow that leads
Most heart diagrams show the left atrium and ventricle on the right side of the diagram. Imagine the heart in the body of a person facing you. The left side of their heart is on their left, but since you are facing them, it is on your right.
This experiment is mainly focus on the cell development performance in different birth weight groups. The cardiac muscle hypotrophy and muscle weakness direct affect muscle function and cause disease. With the cellular study, it could better explain how the glucose pathways affect cardiac energy use and phenotype development. If the left ventricular hypotrophy phenotype has directly connect with glucose intake, then with this study, LBW ventricular muscle can be more sensitive to the signal pathway
The cardiac muscle cells can be affected by heart disease through the inability to maintain its homeostasis through the calcium pump. If there is excess calcium within the heart it results in the in ability of the heart muscle to relax. As a result, the ADP/ATP ratio increases, phosphocreatine decreases, and energy stores are depleted. Furthermore, this imbalance affects the energy needed to relax the left ventricle. Secondly, diastolic heart failure can occur from changes in preload, afterload, renin-angiotension-aldosterone system, and the sympathetic nervous system. These changes affect the fibrillar collagen within the extracellular matrix that affects the ability of the ventricular to relax. These changes along with those compensatory mechanisms results in continuous resistance that results in increased in left ventricular end-diastolic pressure (McCance & Huether, 2010).
In the valvular disease the regurgitation of blood back to the ventricles occurs when the valves fail to close tightly and this will result in ventricular overload and increased muscle stretching. This increases the heart muscles need for oxygen and energy resulting in the cardiac muscles to contract harder (Karch, 2013). The failure of the left ventricle to pump efficiently will lead to pulmonary vessel congestion and in severe cases, pulmonary edema whereas the inefficient pumping of right ventricle will lead to liver congestion and peripheral edema (edema of the legs and feet). The cardiovascular system works as a closed system and therefore, if one-sided failure left untreated, will eventually lead to failure of both sides (Karch, 2013). The American College of Cardiology (ACC)/ American Heart Association (AHA) has incorporated a classification system of heart failure that include four stages. This staging system (stage A to stage D) recognizes that there are established risk factors and structural abnormalities that are characteristics of the four stages of heart failure.
of atria and ventricle. Impulses not being transmitted from atria to the ventricle; no whole number relationship between atrial and ventricular contractions was demonstrated.
6. Automaticity – ability of heart to beat spontaneously and repetitively without external neurohormonal control. The heart is capable of beating outside the body, given proper laboratory conditions. Automaticity is evidently linked to fluid and electrolyte balance rather than to nervous system control.
reports the amount of force exerted by the blood into the arteries during ventricular contraction.
While contraction in skeletal muscle is triggered by motor neurons under central control, certain cardiac muscle variants exhibit autorhythmicity. This means that that they are capable of producing their own depolarizing electrical potential. The cardiomyocytes that are capable of producing their own electrical potentials are found in what is referred to as the electrical condition system of the heart. This system is comprised of specializes cardiomyocytes that are autorhythmic and are able to conduct electrical potentials rapidly. These specialized structures include the sinoatrial node, atrioventricular node and bundle, and Purkinje fibers.