Cardiovascular | Anatomy of the Heart | Heart Model

Introduction to the Heart

In this section, the instructor introduces the different surfaces of the heart and provides an overview of its structures.

Surface and Structure of the Heart

• The anterior surface of the heart is shown, with the posterior surface at the back, inferior surface at the bottom (apex), and superior surface at the top.

• The left side has a fatty pouch called the left auricle, which helps squeeze blood into the atria.

• The pulmonary trunk carries deoxygenated blood from the right ventricle to the lungs for oxygenation.

• The left pulmonary artery branches off from the pulmonary trunk.

• The aorta is a large vessel that carries oxygenated blood out of the heart. It has three branches: brachiocephalic artery, left common carotid artery, and left subclavian artery.

Right Side of Heart

This section focuses on exploring structures on the right side of the heart.

Right Atrium and Superior Vena Cava

• The right atrium receives blood from systemic veins through two main vessels: superior vena cava and inferior vena cava.

• The superior vena cava is formed by merging right and left brachiocephalic veins.

• Another vein called azygos vein feeds into superior vena cava.

Pulmonary Artery and Veins

• The pulmonary artery carries deoxygenated blood from the right ventricle to lungs for oxygenation. There are separate right and left pulmonary arteries.

• Pulmonary veins carry oxygenated blood back to the heart from lungs. They appear red in color.

Posterior Portion of Heart

This section explores the posterior portion of the heart.

Azygos Vein and Coronary Circuit

• The azygos vein runs along the back of the heart, connecting to the superior vena cava.

• The descending aorta can be seen, which continues as thoracic and abdominal aorta.

• The coronary circuit will be discussed in detail after removing a piece from the heart.

Conclusion and Coronary Circuit

In this final section, the instructor concludes and introduces the coronary circuit.

Coronary Circuit

• The instructor mentions that they will show the coronary circuit after removing a piece from the heart.

Anatomy of Coronary Arteries and Veins

In this section, the anatomy of coronary arteries and veins is discussed. The left anterior descending artery, circumflex artery, great cardiac vein, posterior vein of the left ventricle, right coronary artery, marginal artery, small cardiac vein, anterior cardiac veins, and posterior interventricular artery are covered.

Left Anterior Descending Artery

• The left anterior descending artery is also known as the anterior interventricular artery.

• It supplies a significant portion of muscle to the anterior walls of the ventricles and the interventricular septum.

• About 40% of myocardial infarctions occur within this artery due to blockage.

Circumflex Artery

• The circumflex artery wraps around the auricle and supplies some of the atrial muscular wall and lateral walls of the left ventricle.

Great Cardiac Vein

• The great cardiac vein runs parallel to the anterior interventricular artery.

• It drains deoxygenated blood from the myocardium back to the heart.

Posterior Vein of Left Ventricle

• This vein drains deoxygenated blood from the posterior side of the heart.

Right Coronary Artery

• The right coronary artery runs down in a groove called coronary sulcus.

• It gives off branches such as marginal artery that supplies lateral walls of the right ventricle.

Small Cardiac Vein

• The small cardiac vein accompanies the marginal artery.

• It drains deoxygenated blood back to the heart.

Posterior Interventricular Artery

• This branch runs through a groove called posterior interventricular sulcus.

• It delivers oxygen-rich blood to myocardium on its pathway.

Summary

The transcript discusses various arteries and veins in the anatomy of the heart. The left anterior descending artery supplies a significant portion of muscle to the anterior walls of the ventricles and is commonly associated with myocardial infarctions. The circumflex artery wraps around the auricle and supplies some atrial muscular wall and lateral walls of the left ventricle. The great cardiac vein runs parallel to the anterior interventricular artery, while the posterior vein of the left ventricle drains deoxygenated blood from the posterior side of the heart. The right coronary artery gives off branches such as marginal artery, which supplies lateral walls of the right ventricle. The small cardiac vein accompanies this artery. Finally, there is a discussion on the posterior interventricular artery that delivers oxygen-rich blood to myocardium through its pathway.

This summary provides an overview of key points discussed in relation to coronary arteries and veins in heart anatomy.

New Section

This section provides an overview of the blood flow in the heart and highlights arterial anastomoses.

Blood Flow and Arterial Anastomoses

• The blood from various veins combines and enters the coronary sinus, which then dumps it into the right atrium through the inferior vena cava.

• The posterior interventricular artery forms an anastomosis with the marginal artery, providing a collateral route for blood flow.

• The circumflex artery can also anastomose with both the posterior interventricular artery and the anterior interventricular artery.

• The anterior interventricular artery forms an additional anastomosis with the marginal artery.

• Arterial anastomoses ensure alternative routes for blood flow in case of blockages or clots, ensuring sufficient oxygen supply to tissues.

New Section

This section explores the internal structures of the heart, including chambers and valves.

Internal Structures of the Heart

• The right atrium receives blood from various veins and is separated from the right ventricle by the tricuspid valve. Chordae tendineae anchor this valve to papillary muscles.

• Scar tissue called fossa ovalis replaces the foramen ovale after birth, allowing blood shunting between atria during fetal circulation.

• The opening of the coronary sinus is located in the right atrium, receiving blood from multiple cardiac veins.

• The right ventricle pumps blood through the pulmonary semilunar valve into pulmonary arteries. A ligamentum arteriosum (formerly ductus arteriosus) shunts blood from the pulmonary trunk to the aorta in fetal circulation.

New Section

This section concludes the exploration of internal heart structures and their functions.

Internal Heart Structures (Continued)

• The ligamentum arteriosum becomes a ligament after birth, closing off the shunt between the pulmonary trunk and aorta.

The transcript is already in English, so there is no need to translate it.

New Section

This section provides an overview of the anatomy of the heart, focusing on the left side and its functions.

Left Pulmonary Veins and Mitral Valve

• The left pulmonary veins are responsible for carrying oxygenated blood from the left lung to the left atrium.

• The mitral valve, also known as the bicuspid valve, prevents backflow of blood from the left ventricle to the left atrium.

• The mitral valve has collagen cords called chordae tendineae that anchor it and papillary muscles that support these cords.

Aortic Semilunar Valve and Interventricular Septum

• The aortic semilunar valve prevents backflow of blood from the aorta into the left ventricle.

• The thick structure seen is called the interventricular septum, which separates the two ventricles.

• Certain defects like tetralogy of Fallot can cause septal defects where blood can flow between the ventricles.

Myocardium and Endocardium

• The muscular layer of the heart is made up of cardiac muscle, known as myocardium.

• The internal chambers of the heart are lined with simple squamous epithelial tissue called endocardium.

• Endocardium also lines the valves within the heart.

Pectinate Muscles and Trabeculae Carneae

• Pectinate muscles are found in the anterior wall of atria and have a comb-like appearance.

• Trabeculae carneae are irregular fibers of muscle found in the anterior walls of ventricles.

Epicardium

• The outer layer of the heart is called epicardium, consisting of mesothelium tissue.

• Epicardium is made up of simple squamous epithelial tissue with some areolar connective tissue.

New Section

This section provides a summary of the different layers and structures of the heart.

Layers of the Heart

• The heart has three main layers: epicardium, myocardium, and endocardium.

• Epicardium is the outer layer, consisting of mesothelium tissue.

• Myocardium is the middle layer, composed of cardiac muscle.

• Endocardium is the inner lining of the heart chambers and valves.

Internal Structures

• Pectinate muscles are found in the anterior wall of atria.

• Trabeculae carneae are irregular fibers of muscle found in the anterior walls of ventricles.

Conclusion

• The anatomy and structure of the heart play crucial roles in its function as a pump for circulating blood throughout the body.