THE HEART
The heart is an involuntary muscle composed by four chambers that weight about 400 grammes. It has a particular conical form and it is as big as the fist of the person .
The heart is made up by three tissues, from outside to inside, they are: pericardium, myocardium and endocardium.
Interiorly it's divided in four cavities (or chambers) , two uppers and two lowers, called, respectively, atrium and ventricle.
The two uppers cavities are separated from the lower ones by intera trial septum that proceed to become interventricular while atrium and ventricle on the same side comunicate through valves.
The human heart, has two circulations: systematic and pulmonary circulation. But how does circulation work? It works by means of two veins, the blood rich of carbon dioxide returns to right atrium, goes on into right ventricle and completes its trip in the lungs where gaseous exchange occur and carbon dioxide converts into oxygen. After the transformation,"clear" blood goes back to heart into left ventricle and through the aorta and then it's pumped through the body.
Did you know that the heart executes 300 pulses per minute pumping 200.000.000 litres of blood?
Well, yes. All this following the regular harmonic motion.
The heart in physics
In physics the harmonic motion is the projection of a uniform circular motion on the X or Y axis. Consequently the trajectory covered by the material point is a circumference.
The harmonic motion: the speed of an object in uniform circular motion is constant and it acquires the value of 2πr/T where r is the circumference radius and T is the period: the interval of time in which the object travels the entire circumference.
If we consider P as the material po
int and Q as its projection on X’saxis, we can see that P, moving at constant speed, will travel along the whole circular trajectory while its projection Q will move along the circumference’s diameter AB.
How will the projection Q move if point P travels on a uniform circular motion?
Q will oscillate back and forth along the AB diameter.
The swing and the spring are examples of phenomenons in which the object oscillates between two extremities.
Depiction of the harmonic motion on the time-spacegraphic
The harmonic motion in space-time graphic is depicted as a curve which oscillates in a regular way and it is called sine curve.
An example of an harmonic motion graphic depiction is the ECG, which reproduces graphically the heart’s electric activity.