Right heart and left heart, how different are they really? – Physiology for students of basic medical science.

    • Receives and pumps CO2 RICH BLOOD.
    • Blood comes from the system through the superior and inferior vena cava.
    • Inspiration will create negative pressure within the thorax “aspirating” blood into the right atrium as venous return increases.
    • During diastole, blood enters the right ventricle through an wide open tricuspid valve.
    • Ventricle dilation is an active process which also sucks blood in.
    • The pulmonary valve closes producing the second cardiac sound.
    • Then, during the last part of diastole, the right atrium contracts and injects one more small quantity of blood, a “final kick” if you may. This will contribute to filling the ventricle appropriately thus improving the systolic contraction afterwards (explained by the Frank Starling law)
    • Finally the right ventricle contracts during systole, tricuspid valve closes tight producing the first cardiac sound and blood is ejected powerfully through the pulmonary trunk and arteries into the lungs where gasses will be exchanged so that blood becomes oxygen-rich.
    • Right heart failure will cause symptoms of vascular congestion, specially in those regions where veins are close to the cava system: Yugular ingurgitation, limb edema, hepatosplenomegaly, and ultimately pleural effusion and ascitis.
Right heart systole and first heart sound from a closing tricuspid valve  – Click to enlarge and download.
Right heart diastole and second heart sound from a closing pulmonary valve – Click to enlarge and download.
    • Blood comes from the lungs, rich in oxygen, bright red, through the pulmonary VEINS and into the left atrium. Air inspiration helps this process by creating negative pressure inside the thorax. It improves venous return.
    • During diastole the left ventricle dilates, actively, sucking blood the is arriving in the atrium, while the mitral valve is open and aortic valve closes.
    • The closing the aortic valve during diastole produces the second sound of the heart.
    • At the end of the diastole, the left atrium contracts, thanks to the beginning of the cardiac cycle and the sinus node. This final “kick” of blood into the left ventricle will improve end diastolic volume. This contributes to fiber elongation creating a stronger systolic contraction afterwards (explained by the Frank Starling law).
      • In an atrial fibrillation situation, this final kick is lost and end diastolic volume decreases. In situations of high metabolic demands, with tachycardia, symptoms of heart failure may appear due to poor filling and poorer systolic contraction.
    • During the powerful left ventricle contraction, systole occurs, closing the mitral valve, causing the first cardiac sound, and as the aortic valve opens, blood powerfully is pump all over the system through the huge aorta system and all its stems and branches.
    • Left ventricle failure will be responsible of symptoms of poor oxygenation (oxygen rich blood is not reaching the peripheral tissues): Dyspnea, pallor, cold skin, poor pulses and signs of bad tissue perfusion.
Left heart systole and first heart sound from a closing mitral valve – Click to enlarge and download.
Left heart diastole and an aortic valve closing producing the second heart sound – Click to enlarge and download.
  • Thank you for stopping by the Plague Doctor’s blog. If you like these illustrations and the blog please leave a comment and tell me what you think. You opinion is of most importance. Tell your friends about it and visit us at facebook, twitter, instagram or tumblr. Download the illustrations for free and print it. A3 should be fine for you to put it up your wall and review anytime you like. Thank you!

-The Plague Doctor

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