Cardiovascular | Anatomy of the Heart | Heart Model

Overview of the Heart's Anatomy

Anterior and Posterior Surfaces

• The heart's anterior surface is identified, with the posterior surface located at the back, inferior surface at the bottom, apex at the tip, and superior surface or base pointing towards the right shoulder.

Auricles and Atria

• The left auricle is described as a fatty pouch that helps squeeze blood into the left atrium; it contains muscle tissue for this function.

• The right auricle is noted alongside the pulmonary trunk, which carries deoxygenated blood from the right ventricle to the lungs for oxygenation.

Major Blood Vessels

• The aorta is introduced as a major vessel emerging from the heart, with its ascending portion and arch leading to three key arteries: brachiocephalic artery, left common carotid artery, and left subclavian artery.

• The superior vena cava drains into the right atrium; it merges from both sides via right and left brachiocephalic veins.

Pulmonary Arteries and Veins

Function of Pulmonary Vessels

• Right and left pulmonary arteries transport deoxygenated blood to lungs (appear blue), while pulmonary veins return oxygenated blood (appear red).

Azygos Vein

• The azygos vein connects to superior vena cava; it plays a role in bypassing inferior vena cava during certain conditions like pregnancy.

Coronary Circulation

Coronary Arteries

• Two main coronary arteries branch off from ascending aorta: right coronary artery and left coronary artery.

• The anterior interventricular artery (left anterior descending artery), crucial for supplying heart muscle, is highlighted due to its association with myocardial infarctions.

Circumflex Artery

• Circumflex artery wraps around providing blood supply to lateral walls of ventricles but has lower incidence of blockages compared to other arteries.

Cardiac Veins

Great Cardiac Vein

• After delivering oxygen, blood returns through great cardiac vein adjacent to anterior interventricular artery.

Other Cardiac Veins

• Posterior vein of left ventricle drains myocardium; small cardiac vein also contributes by draining areas supplied by right coronary artery.

Coronary Sinus

Collection Point for Venous Blood

• Multiple cardiac veins converge into coronary sinus which empties into right atrium along with inferior vena cava.

Anastomoses in Coronary Circulation

Importance of Anastomoses

• Various anastomoses between arterial branches provide collateral routes for blood flow ensuring adequate oxygen delivery even if one pathway becomes blocked.

Internal Structures of Heart Chambers

Atria and Ventricles Overview

• Right atrium separates from right ventricle via tricuspid valve supported by chordae tendineae anchored by papillary muscles.

Fetal Remnants

• Foramen ovale becomes fossa ovalis post-birth; opening for coronary sinus noted in right atrium structure description.

Left Side Heart Structures

Oxygenated Blood Flow

• Left side receives oxygenated blood from lungs through pulmonary veins; mitral valve regulates flow into left ventricle where further pumping occurs.

Valves in Ventricles

• Aortic semilunar valve prevents backflow into left ventricle after contraction; interventricular septum noted as muscular wall separating ventricles.

Myocardial Structure

Muscle Layers

• Myocardium consists primarily of cardiac muscle tissue while endocardium lines internal chambers including valves with simple squamous epithelial tissue covering them.