Main Functions and important role of  heart in human beings

The heart is made up of four chambers: two upper chambers known as the left atrium and right atrium and two lower chambers called the left and right ventricles. It is also made up of four valves: the tricuspid, pulmonary, mitral and aortic valves.

Anatomy of the heart

• Left atrium and auricle. Left atrium. Left auricle.
• Right atrium and auricle. Right atrium. Right auricle.
• Interventricular septum and septal papillary muscles. Interventricular septum.
• Right ventricle and papillary muscles. Right ventricle.
• Left ventricle and papillary muscles. Left ventricle.

Tissue types in heart & Location of the Heart

Histologically, the heart is made of three layers of tissue:

 1-epicardium,2- myocardium, 3-endocardium.

The human heart is located within the thoracic cavity, medially between the lungs in the space known as the mediastinum.  Within the mediastinum, the heart is separated from the other mediastinal structures by a tough membrane known as the pericardium, or pericardial sac, and sits in its own space called the pericardial cavity.

The dorsal surface of the heart lies near the bodies of the vertebrae, and its anterior surface sits deep to the sternum and costal cartilages. The great veins, the superior and inferior venae cavae, and the great arteries, the aorta and pulmonary trunk, are attached to the superior surface of the heart, called the base.

Shape and Size of the Heart

The shape of the heart is similar to a pinecone, rather broad at the superior surface and tapering  to the apex. A typical heart is approximately the size of your fist: 12 cm (5 in) in length, 8 cm (3.5 in) wide, and 6 cm (2.5 in) in thickness. Given the size difference between most members of the sexes, the weight of a female heart is approximately 250–300 grams (9 to 11 ounces), and the weight of a male heart is approximately 300–350 grams (11 to 12 ounces).

Chambers and Circulation through the Heart:

The human heart consists of four chambers: The left side and the right side each have one atrium and one ventricle. Each of the upper chambers, the right atrium (plural = atria) and the left atrium.

Membranes, Surface Features, and Layers:

Our exploration of more in-depth heart structures begins by examining the membrane that surrounds the heart, the prominent surface features of the heart, and the layers that form the wall of the heart. Each of these components plays its own unique role in terms of function.

Internal Structure of the Heart:

Recall that the heart’s contraction cycle follows a dual pattern of circulation—the pulmonary and systemic circuits—because of the pairs of chambers that pump blood into the circulation.