The Human Heart structure with diagram
The heart is a hollow, fibromuscular organ. It is somewhat conical or pyramidal in form. It is roughly the size of a closed fist. An average heart measures 12 cm from base to the apex. Transverse diameter at its broadest region is 8-9 cm. It is 6 cm thick antero-posteriorly. While in adult male the heart weighs 280-340 g, in female it weighs 230-280 g.
The thoracic organs such as heart, trachea and oesophagus form a midline partition called the mediastinum. The heart lies obliquely in the medi-astinum.
The heart is surrounded by a double layered membrane called the peri-cardium. The outer layer is called the fibrous pericardium. The inner mem-brane is called the serous pericardium. In between heart and pericardium, there is a pericardial space. This space is filled with a fluid called the pericardial fluid.
The wall of the heart is made up of three tissue layers. They are the epicardium, myocardium and endocardium. The epicardium forms the smooth outer surface of the heart. The middle myocardium is composed of cardiac muscle. This layer plays an important role in the functioning of the heart. Theendocardium forms the smooth inner surface. It is formed of squamous epithelium.