What is the heart and what is its main function?

The heart is a hollow muscular organ located in the middle mediastinum. Its primary function is to act as a dual pump, circulating blood through the systemic and pulmonary circulations.

What are the four chambers of the heart and their basic roles?

The heart has four chambers: Right atrium receives deoxygenated blood from the body. Right ventricle pumps deoxygenated blood to the lungs. Left atrium receives oxygenated blood from the lungs. Left ventricle pumps oxygenated blood to the body and has the thickest wall.

What are the main valves of the heart and where are they located?

The heart has two types of valves: Atrioventricular valves include the Tricuspid valve (between right atrium and ventricle) and Mitral/Bicuspid valve (between left atrium and ventricle). Semilunar valves include the Aortic valve (at the aorta) and Pulmonary valve (at the pulmonary artery).

How does the heart's conducting system work to regulate heartbeat?

The conducting system consists of specialized fibers that initiate and propagate electrical impulses: SA node acts as the pacemaker in the right atrium. AV node delays impulses to allow atrial emptying. AV bundle and branches transmit signals to the ventricles. Purkinje fibers ensure coordinated ventricular contraction.

What are some common clinical conditions related to the heart?

Common conditions include: Murmurs are abnormal valve sounds due to pathology. Mitral stenosis often results from rheumatic fever, causing left atrial enlargement. Cardiac tamponade is compression from fluid in the pericardial sac, impairing filling. Arrhythmias are irregular rhythms like tachycardia or bradycardia.

Where is the apex of the heart located and why is it clinically important?

The apex is formed by the left ventricle and lies at the left 5th intercostal space, about 9 cm from the midline. It is the site of the apex beat (point of maximal impulse), which can shift in conditions like cardiomegaly or dextrocardia.

What are the external features and surfaces of the heart?

Key external features include: Apex and base formed by left ventricle and left atrium, respectively. Grooves include coronary sulcus (between atria and ventricles) and interventricular sulci (between ventricles). Surfaces are sternocostal (mostly right chambers), diaphragmatic (both ventricles), and left surface (mainly left ventricle).

Heart Anatomy – Chambers, Valves & Conduction System

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