Question

define whole working of the heart

Answer 1

$\textbf{STRUCTURE OF HEART}$

→ Heart is a hollow, muscular organ present in between two lungs in tye thoraric cavity. It's size is about one's fist. It is 12 cm long and 6 cm wide.

→ It's weight in male is 300 gm and 250 gm in female. It's is reddish brown in colour.

→ It's upper broad part is known as base and lower part is known as Apex.

→ It's is protected by a double members called pericardium, comprising inner visceral pericardium and outer parietal pericardium.

→ Between these layers there is a fluid called pericardium fluid. This fluid provides moisture to the heart and reduce the friction between heart wall and surrounding tissue.

→ A human heart is four chambered. Two upper; smaller chambers called atria and the lower; longer chambers called ventricle.

→ The atrium and ventricle of the same side are separated by atrio-ventricular septum.

→ Atrial septum separates the left and right atria. Inter ventricular septum separates the left and right ventricles.

→ The opening between right atrium and ventricle is guarded by a valve called Tricupsid valve.

→ And the opening between left atrium and ventricle is guarded by a Bicuspid valve.

→ Valves prevent the backward flow of blood and allow the blood to flow in one direction only.

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$\textbf{WORKING OF HEART}$

→ First of all, all the deoxygenated blood from the body with the help of superior and inferior vena cava came in heart.

→ After it, it came in Right atrium and then Right ventricle.

→ Contraction of auricles derives most of the blood in into the ventricle. At the end of the auricular systole, auricles start relaxing and the contraction of the ventricles simultaneously.

→ As the contraction of the ventricles begins, the pressure of the blood in the auricles rises. With this pressure, the flaps of the auricular ventricular (A-V) valves are pushes up and meet to close the A-V apertures. This tight closure of the A-V valves at the start of the ventricular contraction produces the first heart beat, which is "Lub".

→ Now the ventricles start relaxing. The semilunar valve close as they get filled the blood trying to return and meet together, closing the outlets of the great arteries.

→ The closing of the semilunar valves at the start of diastole produces the second heart sound "Dup".

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Answer 2

$\textbf{Answer is in Attachment !}$