Anatomy of the Heart - External & Internal Structures

Introduction

This tutorial provides a comprehensive overview of the anatomy of the heart, detailing both external and internal structures. Understanding these structures is essential for students, healthcare professionals, and anyone interested in human biology. We will explore the blood circulation system, identify the heart's external features, and delve into its internal anatomy.

Step 1: Understand the Blood Circulation System

The heart plays a crucial role in the circulatory system, which is divided into two main parts:

1. Pulmonary Circulation (Circulus Sanguis Minor)

   • Deoxygenated blood from the body enters the right atrium via the superior and inferior vena cava.
   • Blood flows through the tricuspid valve into the right ventricle.
   • The right ventricle pumps blood through the pulmonary valve into the pulmonary artery.
   • The pulmonary artery carries blood to the lungs for oxygenation.

2. Systemic Circulation (Circulus Sanguis Major)

   • Oxygenated blood returns from the lungs to the left atrium.
   • Blood moves through the bicuspid valve into the left ventricle.
   • The left ventricle pumps blood through the aortic valve into the aorta.
   • The aorta distributes oxygenated blood to the rest of the body.

Step 2: Explore the External Structures of the Heart

Familiarize yourself with the key external features of the heart:

• Apex of the Heart (Apex Cordis)
• Base of the Heart (Basis Cordis)
• Pulmonary Surface (Facies Pulmonalis)
• Sternocostal Surface (Facies Sternocostalis)
• Diaphragmatic Surface (Facies Diaphragmatica)
• Right Border of the Heart (Margo Dexter Cordis)
• Coronary Sulcus (Sulcus Coronarius)
• Anterior Interventricular Sulcus (Sulcus Interventricularis Anterior)
• Posterior Interventricular Sulcus (Sulcus Interventriculare Posterior)

Step 3: Investigate the Internal Structures of the Heart

Understanding the internal anatomy is crucial for recognizing how the heart functions:

1. Septum of the Heart (Septum Cordis)

   • Interventricular Septum (Septum Interventriculare)
     • Muscular Part (Pars Muscularis)
     • Membranous Part (Pars Membranacea)
   • Interatrial Septum (Septum Interatriale)

2. Right Atrium Anatomy

   • Anterior Wall: Right Auricle (Auricula Dextra)
   • Lateral Wall: Pectinate Muscle (Musculus Pectinati)
   • Superior Wall: Opening of Superior Vena Cava
   • Posterior Wall: Openings for inferior vena cava and sinus of vena cava
   • Medial Wall: Interatrial Septum and openings for coronary sinus
   • Inferior Wall: Right Atrioventricular Opening and Tricuspid Valve

3. Right Ventricle Anatomy

   • Base: Right Atrioventricular Opening and Opening of Pulmonary Trunk
   • Features: Trabeculae Carneae and Papillary Muscles
   • Tricuspid Valve: Composed of anterior, posterior, and septal cusps
   • Pulmonary Valve: Includes semilunar cusps and sinus of pulmonary trunk

4. Left Atrium Anatomy

   • Anterior Wall: Left Auricle and Pectinate Muscle
   • Posterior Wall: Openings of Pulmonary Veins
   • Medial Wall: Interatrial Septum
   • Anterior Wall: Left Atrioventricular Opening and Mitral Valve

5. Left Ventricle Anatomy

   • Left Atrioventricular Opening: Bicuspid Valve with anterior and posterior cusps
   • Aortic Opening: Aortic vestibule and aortic valve
   • Features: Trabeculae Carneae, Papillary Muscles, and Tendinous Chords

Conclusion

In this tutorial, we examined the anatomy of the heart, focusing on its external and internal structures as well as the blood circulation process. Understanding these components is vital for anyone studying medicine or biology. As a next step, consider exploring how these structures work together during a heartbeat and the physiological implications of any anatomical variations.