Heart Location and Size
The heart is asymmetrically placed, primarily on the left side of the thoracic cavity, between the lungs. Surprisingly, it's about the size of your own clenched fist, weighing approximately 250-350 grams.
Unique Myocardial Structure
Heart muscle cells, or cardiomyocytes, have a unique interconnected structure that forms a syncytium, allowing rapid electrical conductivity. This enables synchronized contractions, a remarkable and distinctive feature of cardiac muscle.
Four Chambers Functionality
The heart consists of four chambers: two atria and two ventricles. Atria collect blood, while ventricles pump it out. The right side circulates blood to the lungs, and the left side pumps oxygenated blood to the body, a setup known as double circulation.
Electrical Impulse Journey
The sinoatrial (SA) node, the heart's natural pacemaker, initiates the heartbeat, triggering an electrical impulse that travels through the atria, atrioventricular (AV) node, bundle of His, and Purkinje fibers, coordinating heartbeats with precision.
Heart Valves' Critical Role
The heart's four valves ensure unidirectional blood flow and prevent backflow. Each 'lub-dub' sound you hear is the closing of the mitral/tricuspid and aortic/pulmonary valves, respectively. Valve dysfunction can lead to life-threatening heart conditions.
Coronary Circulation
The heart's own vascular system, the coronary arteries, branch off the aorta, supplying the heart muscle with oxygen-rich blood. Notably, these arteries fill during heart relaxation, not contraction, an exception to how we typically consider blood flow.
Remarkable Regenerative Capacity
Contrary to popular belief, the heart does have a limited ability to regenerate cells, but at a much slower rate than other tissues. Research into enhancing this ability could revolutionize treatment for heart disease.
Where is the heart primarily located?
Center of thoracic cavity
Right side of thoracic cavity
Left side of thoracic cavity
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