Answer in short - describe the various stages of heart beat and direction of blood flows in them
Answers
Heart has four separate chamber i.e, right atrium ,left atrium, right ventricle,left ventricle
The oxygen rich blood from the lungs come to the left upper chamber of the heart known as the left atrium.The left atrium relaxes when the blood enter into it .Then it contract and the blood from this enters the thick wall ,left ventricle.When the left ventricle contract the blood is pump out to the different part of the body.Deoxygenated blood returning from different part of the body enter the right atrium when it expand.As the right contract ,the blood from here enters the right ventricle .When the right ventricle contract in turn deoxygenated blood from here is pump to the lungs for oxygenation .
Answer- Stage of heartheat and flow of blood in human heart: The heart is formed of cardiac muscles which have the properties of excitability, autorhythmic contractility and conductivity. So when the cardiac muscles are stimulated properly, these get excited and conduct the excitation waves as cardiac impulses on the wall of heart chambers which undergo rhythmic contraction. Due to this, blood flows in a specific and unidirectional manner, while backflow of blood is prevented by the valves present inside the heart chambers. Contraction of cardiac muscles is called systole, while relaxation of cardiac muscles os called diastole.
(a) Atrial diastole:- In this, atrial muscles relax, so atria increase in size and receive the blood from the veins. Right auricle receives deoxygenated blood from most of the body parts by great veins, while left auricle receives oxygenated blood from the lungs by pulmonary veins.
(b) Atrial systole:- It involves contraction of atrial muscles. Due to this, deoxygenated blood is pumped into right right ventricle, while oxygenated blood is pumped into left ventricle. Ventricles relax to receive the blood.
(c) Ventricular systole:- It involves contraction of ventricular muscles. Due to this, deoxygenated blood from right ventricle is carried to the lungs by pulmonary arch, while oxygenated blood from left ventricle is carried to other body parts by systemic aorta and its branches.
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