why are the right & left sides of the heart separated by a muscular wall?
966426
The reason why it is there is that it is more efficient to have a wall. It separates oxygenated from non-oxygenated blood so only oxygenated blood is sent to muscles.\n\nAmphibians and reptiles don't have a wall separating the oxygenated from non-oxygenated blood, they are alive, but their circulatory system is less efficient because some of the blood travelling to the muscles doesn't contain any oxygen.
19752
Not actually, in fact from olden times, they were inferior.  The myth goes that left-handed and right-handed people were in equal numbers.  However, the human heart is slightly on the left side of the body.  So during a war a right-handed person held his shield in the left hand which protected his heart from a direct enemy strike.  However, for a left-handed person, he held a sword in his left hand and so the possibility of him taking a fatal strike on the heart was manifold.  This probably resulted in the death of a lot of left-handed people making the right-handed people a majority.  The left-handed people who survived were smart enough to protect themselves, and hencce, the myth that left-handed people are superior.
388349
The right lung has three lobes (superior, middle, and inferior from top to bottom), and the left only has two (superior and inferior).  \n\nA side note: this difference has been attributed to the fact that the heart resides a bit more in the left chest than the right, and three lobes plus the heart would be a bit too snug for the lungs or heart to function properly.
223360
The coronary arteries originate OUTSIDE of the heart, both left and right ostiums come from the aorta.\n  There are many within the heart such as the AV brandh of the right, the septals from the left as well as diagonals from the Left anterior descending and the om 1 and 2 from the circumlex artery.\n  Of the left mainstem is the left side which has the LAD and circumflex and intermediate.\n   From the right is the right coronary artery which has branches called the conus, AV, and then bifurcates to the PDA and pvl.
108270
Because most people are right handed and your right hand is more away from you heart so as to let your brain make your decision, not your heart.May God bless......
869365
There is not a voluntarty "part" of your heart.  The heart is controlled by the automic nervous system, comprised of the sympathetic and parasympathetic, which are your "fight or flight" portions of your nervous system.  Your somatic nervous system controls the voluntary muscles, like the skeletal muscles.\n\nCheck this site out:  http://163.1.0.40/wfsa/html/u05/u05_010.htm
88871
The heart is divided into the upper right atria and upper left atria (plural atrium), and the lower right and left ventricles. A septum divides them. Blood from the veins carries oxygen depleted blood, fewer red blood cells, to the heart and the arteries carry oxygen enriched blood to the body. It is the hearts job, a poweful muscle, to pump blood through the body.\n\nFor more imformation please click on the blue link below in the sources box.
326091
The walls of the heart are made up of three layers, while the cavity is divided into four parts. There are two upper chambers, called the right and left atria, and two lower chambers, called the right and left ventricles. The Right Atrium, as it is called, receives blood from the upper and lower body through the superior vena cava and the inferior vena cava, respectively, and from the heart muscle itself through the coronary sinus. The right atrium is the larger of the two atria, having very thin walls. The right atrium opens into the right ventricle through the right atrioventicular valve(tricuspid), which only allows the blood to flow from the atria into the ventricle, but not in the reverse direction. The right ventricle pumps the blood to the lungs to be reoxygenated. The left atrium receives blood from the lungs via the four pulmonary veins. It is smaller than the right atrium, but has thicker walls. The valve between the left atrium and the left ventricle, the left atrioventicular valve(bicuspid), is smaller than the tricuspid. It opens into the left ventricle and again is a one way valve. The left ventricle pumps the blood throughout the body. It is the Aorta, the largest artery in the body, which originates from the left ventricle.
893140
Because if the shock is between the two hands, the current must travel through the main part of the body and can interfere with the heart.
354452
process of elimination. of the 3 muscle types, smooth muscle is the only type withou cross-straitions. these stripes contribute to the fact that cardiac muscle and skeletal muscle contract in the same way. however the heart muscle, intimately interconnected continuous fabric,  has its characteristic intercalated discs which connect adjacent myocardial cells mechanically and electrically. the latter being, when one cell is stimulated it passes the electrical pulse throughout the heart and stimulates all cells (measured in ECG).
535500
Sometimes it can be left.\nOther times it can cause infection or later pain.\nAlso sometimes it has invaded an artery it can travel to the heart or other area of the body and create all kinds of problems.
1034068
The wall of the left ventricle is thicker than that of the right ventricle because it has to pump the blood into the aorta and to the whole body. Thicker wall means more muscle and this means greater pumping power.
475819
Because the liver occupies space above the right. And, the blood supply for the right kiney branches off the aorta lower.
369065
firstly the heart isnt in the middle as the answer above states, it is slightly offset.  the reason being is that there is no room in the centre, we have developed (through evolution) so that we need the lungs near the top, the oesophagus needs to be below the mouth and the heart is squeezed in where it can. more of  a design question than biology as other organs take precedence, the heart needs to be high in the torso to pump blood effectively, it needs to be close to the lungs as blood pressure to the lungs needs to be low to prevent haemmorhaging\n\nin other words its not in the middle because it wouldnt fit there
489834
Left ventricle because it has to provide force to push blood through entire body.
616751
Cancer of the heart muscle called angiosarcoma do occur but are rare and\noccur more often in children and more often in the right side of the heart.\nCancers like melanoma are known to spread to the heart. That being said, it\nis somewhat curious why certain tissues are less susceptible to cancer.\nThis is typically ascribed to the belief that the more cells that are\nactively dividing in an organ or tissue the less likely that organ or tissue\nwill have a cancer arise in it.  So skin, intestine and bone marrow which\nhave high populations of dividing cells are more often to have a cancer\narise in their cells than the heart whose muscle tissue is essentially\nnon-dividing.
508331
Right atrium, left atrium, right ventricle, and left ventricle.  The atriums are on the lop left and right sides of the heart, and the ventricles are on the bottom left and right portion.  Unoxygenated blood coming from the parts of the body goes into the right atrium, then via a valve to the right ventricle, then out to the lungs to become oxygenated.  It then comes back from the lungs to the left atrium, to the left ventricle through another valve then back out to the parts of the body again.