Question

explain internal and external structure of heart.​

Answer 1

Answer:

Internal Features

The heart has 4 chambers: Right and left atria and right and left ventricles.

Blood flows normally in the right to left direction: Right atrium to right ventricle to left atrium, and finally to left ventricle.

Oxygen-depleted blood reaches the right atrium via the coronary sinus and superior and inferior vena cava and evacuates the right ventricle via the pulmonary artery towards the lungs.

Oxygen enriched blood then re-enters the left atrium via 4 pulmonary veins and evacuates the left ventricle via the aorta.

External Features

The heart and roots of great vessels are embedded in the pericardial sac, approximately in the center of the thorax. The size of the heart is slightly larger than a clenched fist. The heart is surrounded laterally and posteriorly by the lungs, and anteriorly bound by the sternum and medial sections of the ribs and sterno-costal joints.

It has the shape of a three-sided pyramid with an apex (left anterior), a base (posterior), and 4 surfaces: Sterno-costal/anterior (formed by right ventricle), diaphragmatic/inferior (formed by left ventricle and part of right ventricle), left pulmonary (formed by left ventricle, in contact with left lung), and right pulmonary (formed by right atrium).

The heart appears trapezoid in the posterior and anterior views. As such, it consists of 4 borders: Right (convex), Inferior (horizontal), left (oblique), and superior.

Explanation:

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Answer 2

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The Heart has four chambers :-

• Two Upper atria
• The Receiving chambers
• Two Lower ventricles
• The Discharging chambers.

The Atria open into the ventricles via the atrioventricular valves, present in the atrioventricular septum.

This distinction is visible also on surface of the heart as the coronary sulcus.

The Heart is enclosed in a pericardial sac that is lined with the parietal layers of a serous membrane.

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The External Heart wall has three layer :-

• The Inner Endocardium
• The Middle Myocardium
• The Outer Epicardium.

These are surrounded by a double - membraned sac called the pericardium.

Receives blood from the right atrium via the tricuspid valve during diastole.

It is responsible for moving deoxygenated blood to the lungs for oxygenation and CO2 elimination.

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