what are Function of artium
Answers
Explanation:
There are two atria in the human heart – the left atrium receives blood from the pulmonary (lung) circulation, and the right atrium receives blood from the venae cavae (venous circulation). The atria receive blood while relaxed (diastole), then contract (systole) to move blood to the ventricles.
(1) There are no atrial inlet valves to interrupt blood flow during atrial systole.
(2) The atrial systole contractions are incomplete and thus do not contract to the extent that would block flow from the veins through the atria into the ventricles. During atrial systole, blood not only empties from the atria to the ventricles, but blood continues to flow uninterrupted from the veins right through the atria into the ventricles.
(3) The atrial contractions must be gentle enough so that the force of contraction does not exert significant back pressure that would impede venous flow.
(4) The "let go" of the atria must be timed so that they relax before the start of ventricular contraction, to be able to accept venous flow without interruption.