explain about internal and external structure of heart long answer question 4 marks
Answers
Internal Structure of the Heart
The heart pumps continuously while we are alive.
The heart is a strong muscular pump that circulates and pumps about 2,000 gallons of blood each day and contracts and expands about 100,000 times per day. The normal heart is only as big as an average clenched fist and sits behind the breast bone, or sternum, slightly to the left in between the lungs. Large blood vessels leave and enter the heart and help to keep it in position. The internal structure of the heart consists of four hollow spaces, or chambers, divided by a tissue wall, called the cardiac septum. The flow of blood through the heart is regulated by four valves.
The upper part of the heart is the attachment point for several large blood vessels—the venae cavae, aorta and pulmonary trunk. The upper part of the heart is located at the level of the third costal cartilage.]The lower tip of the heart, the apex, lies to the left of the sternum (8 to 9 cm from the midsternal line) between the junction of the fourth and fifth ribs near their articulation with the costal cartilages
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Internal Structure of the Heart
The heart is a strong muscular pump that circulates and pumps about 2,000 gallons of blood each day and contracts and expands about 100,000 times per day. The normal heart is only as big as an average clenched fist and sits behind the breast bone, or sternum, slightly to the left in between the lungs. Large blood vessels leave and enter the heart and help to keep it in position. The internal structure of the heart consists of four hollow spaces, or chambers, divided by a tissue wall, called the cardiac septum. The flow of blood through the heart is regulated by four valves.
External features of the heart:
The division of the heart into four cavities is indicated on its surface by grooves. The atria are separated from the ventricles by the coronary sulcus (auriculoventriculargroove); this contains the trunks of the nutrient vessels of the heart, and is deficient in front, where it is crossed by the root of the pulmonary artery. The interatrial groove,separating the two atria, is scarcely marked on the posterior surface, while anteriorly it is hidden by the pulmonary artery and aorta. The ventricles are separated by two grooves, one of which, the anterior longitudinal sulcus, is situated on the sternocostal surface of the heart, close to its left margin, the other posterior longitudinal sulcus, on the diaphragmatic surface near the right margin; these grooves extend from the base of the ventricular portion to a notch, the incisura apicis cordis, on the acute margin of the heart just to the right of the apex.