2025-01-23T22:52:40+03:00[Europe/Moscow] en true <p>Why are the walls of the atria very thin</p>, <p>Explain why the left ventricle walls need to be so much thicker than those on the right </p>, <p>Why must the blood in the left side of the heart be kept separate from the blood in the right side </p>, <p>Why is it important that the blood pressure is higher in the heart than elsewhere in the circulatory system </p>, <p>What is the name of the blood vessels on the surface of the heart </p>, <p>Where are contractions initiated </p>, <p>Cardiac cycle (0.8)</p>, <p>Systole </p>, <p>Diastole </p>, <p>Atrial systole </p>, <p>Ventricular systole </p>, <p>Diastole </p>, <p>Flow of the cardiac cycle </p> flashcards
BIOLOGY - BLOOD VESSELS AND CARDIAC SYSTEM

BIOLOGY - BLOOD VESSELS AND CARDIAC SYSTEM

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  • Why are the walls of the atria very thin

    They do not need to pump the blood far so there's no need to generate high pressure

  • Explain why the left ventricle walls need to be so much thicker than those on the right

    Left ventricle needs to pump the blood all around the body (against greater resistance), so it needs to create higher pressure

  • Why must the blood in the left side of the heart be kept separate from the blood in the right side

    Left side contains oxygenated blood, right side contains deoxygenated blood. Allowing mixing would make transport of oxygen less efficient

  • Why is it important that the blood pressure is higher in the heart than elsewhere in the circulatory system

    Blood will flow from high pressure to low pressure. Heart needs higher pressure to maintain flow of blood around the circulatory system

  • What is the name of the blood vessels on the surface of the heart

    Coronary - supplies oxygen/blood to the heart muscle/wall/tissue/cells

  • Where are contractions initiated

    Sino-atrial node in the right atrium, near the opening of the vena cava

  • Cardiac cycle (0.8)

    The sequence of events in one full beat of the heart

  • Systole

    Phases of contraction of cardiac muscle; atrial systole is closely followed by ventricular systole

  • Diastole

    Phase of relaxation of cardiac muscle during which the atria and ventricles fill with blood

  • Atrial systole

    Ventricles relax, atria contracts, pressure increases. Blood moves from atria to ventricles through tricuspid and bicuspid valves. Semilunar valves shut.

  • Ventricular systole

    Ventricles contract and blood pressure increases. Blood pushed out of ventricles through semi-lunar valves into pulmonary artery and aorta. Blood cannot flow backwards due to valves closing. PA carries deoxygenated blood to lungs and aorta takes blood to body

  • Diastole

    Ventricles relax, volume increases, pressure decreases. semi-lunar valves prevent backflow. Atria relax, volume increases, blood moved in via vena cava and pulmonary veins into the heart. All muscles are relaxed.

  • Flow of the cardiac cycle

    RA relaxes and receives blood from the vena cava. When full pressure forces open tricuspid valves and ventricles start to fill. Relaxation of RV draws blood from RA. RA atrium contract pushing blood into RV (fills completely). Atrioventricular valves shut. RV contracts. Semilunar valves open. blood flows into the pulmonary artery to lungs. semilunar valves close. Atrioventricular valves open