Heart Anatomy: Internal Structures and Functions

Septa

• Septa: Walls between the left and right chambers of the heart.
  • Interventricular Septum: Wall between the left and right ventricles.
  • Interatrial Septum: Wall between the left and right atria.

Heart Valves

• Function as one-way valves to ensure proper blood flow.
• Right Atrioventricular Valve (Tricuspid): Between right atrium and right ventricle.
• Left Atrioventricular Valve (Bicuspid/Mitral): Between left atrium and left ventricle.
• Pulmonary Semilunar Valve: Between right ventricle and pulmonary trunk.
• Aortic Valve: Between left ventricle and aorta.

Blood Flow Process

• Entry: Blood from the systemic circuit enters the right atrium via the superior, inferior vena cava, and coronary sinus.
• Right Atrium: Contains fossa ovalis and tricuspid valve with cusps and chordae tendineae attached to papillary muscles.
• Right Ventricle: Blood exits via the conus arteriosus to the pulmonary trunk and through the pulmonary circuit.
• Pulmonary Circuit: Blood delivered to lungs via pulmonary arteries and returns via pulmonary veins to the left atrium.
• Left Atrium: Contracts to push blood through the mitral valve into the left ventricle.
• Left Ventricle: Contracts to push blood through the aortic valve into the aorta (ascending aorta, aortic arch, descending aorta).

Muscle Structures

• Chordae Tendineae: Cord-like tendons connecting cusps to papillary muscles.
• Papillary Muscles: Nipple-shaped muscles connected to chordae tendineae.
• Trabeculae Carneae: Muscle ridges inside the ventricles, resembling a honeycomb.
• Moderator Band: Unique to the right ventricle, it assists in electrical conduction.

Differences Between Right and Left Ventricles

• Right Ventricle: Pumps blood to lungs; contracts medially.
• Left Ventricle: Pumps blood to entire body; contracts like squeezing a water bottle, creating five times the pressure of the right ventricle.
• Wall Thickness: Left ventricle walls are thicker due to high pressure needs.

Functional Anatomy

• Atria have similar structures and functions, moving blood to ventricles.
• Right and left ventricles have same blood volume but different pressure needs due to their respective circulation duties.

These notes summarize the key anatomical structures and functions within the heart as described in the lecture, focusing on septa, valves, blood flow, and muscular arrangements.