Ventricles of the Heart

Overview

• Ventricles are the large, lower chambers of the heart.
• They are responsible for pumping blood into systemic and pulmonary circuits.

Right Ventricle

• Size and Pressure: Smaller than the left ventricle, with lower pressure gradient.
• Valves: Limited by tricuspid and pulmonary valves.
• Features:
  • Three papillary muscles (anterior, posterior, septal).
  • Septomarginal trabecula (moderator band).
  • Pumps blood to the pulmonary circuit.

Location and External Features

• Occupies the anterior surface of the heart.
• Lies between the 3rd and 6th costal cartilages.
• Anterior to the left ventricle, anteroinferior to the right atrium.

Internal Features

• Has an inlet, apical part, and outlet.
• Trabeculae carneae line the ventricle.
• The conus arteriosus leads to the pulmonary valve.
• Supraventricular crest separates the inlet and outlet.
• Papillary muscles attached via chordae tendineae to tricuspid valve.
• Septomarginal band aids in electrical conduction.

Left Ventricle

• Size and Pressure: Larger and with higher pressure gradient.
• Valves: Limited by mitral and aortic valves.
• Function: Pumps blood to systemic circulation.

Location and External Features

• Thick wall, conical shape, elongated.
• Begins at left atrioventricular valve, ends at aortic valve.
• External walls form much of the heart's surface.

Internal Features

• Oval lumen, trabeculated apex.
• Finer trabecular network.
• Papillary muscles larger than those in right ventricle.

Interventricular Septum

• Separates left and right ventricles.
• Comprised of thick muscular and thin membranous parts.
• Supports conducting system of the heart: atrioventricular bundle of His.

Ventricular Function

• Right ventricle pumps to pulmonary circulation, left ventricle to systemic.
• Diastole: Ventricles fill as atrioventricular valves open.
• Systole: Ventricles contract, open semilunar valves, blood ejected.
• Pressure dynamics important for valve function and blood flow.

Embryology

• Heart begins development early, pumps by 4th week.
• Right ventricle arises from bulbus cordis, left from primitive ventricle.
• Interventricular septum forms from endocardial cushions and bulbar ridge.

Ventricular Pathology

• Congenital Disorders: Ventricular septal defect, double outlet right ventricle, hypoplastic ventricles.
• Acquired Disorders: Ventricular hypertrophy, pseudoaneurysm, arrhythmias, bundle-branch block.

Congenital Ventricular Disorders

• Ventricular septal defect: Mixes oxygenated and deoxygenated blood.
• Can lead to right ventricular hypertrophy and hypoxia.

Acquired Ventricular Disorders

• Ventricular Hypertrophy: Caused by increased workload (e.g., atherosclerosis).
• Other Disorders: Include ventricular arrhythmias and bundle branch block.

References

• References include academic literature from journals like Heart and textbooks such as Guyton & Hall's Textbook of Medical Physiology.

Visual and Study Resources

• Videos, quizzes, articles, and diagrams are recommended for deeper learning and assessment.

These notes provide an overview of the heart's ventricular structure, function, development, and associated pathologies, summarizing key anatomical features and clinical implications.