Circulatory System I

Circulatory System I

• The circulatory system comprises the heart, blood vessels, and blood. The cardiovascular system refers solely to the heart and blood vessels.
• The circulatory system's primary function is transporting substances throughout the body via blood.
• Blood serves as the fluid medium for transporting various materials.
• Blood vessels direct blood flow to specific destinations.
• The heart acts as the pump driving blood flow.

Functions of the Circulatory System

• The circulatory system is crucial for transporting substances throughout the body.
• Blood is the liquid medium carrying these substances.
• Blood vessels direct blood to its destinations.
• The heart pumps blood to maintain flow.

Pulmonary and Systemic Circuits

• The cardiovascular system operates through two major divisions:
• Pulmonary circuit: transports blood to the lungs for gas exchange, returning it to the heart.
• Systemic circuit: delivers blood to all body organs (including parts of the lungs and heart wall).

Pathway of Blood Flow Through the Heart

• The right side receives deoxygenated blood returning from the body.
• This blood travels to the lungs for oxygenation.
• Oxygenated blood returns to the left side of the heart.
• Then, the blood is pumped throughout the body.
• The circulatory routes, one through the lungs and the other through the body, are crucial parts of the process.

The Heart Wall

• The heart has three layers:
• Epicardium: a thin outer layer.
• Myocardium: the thick, muscular middle layer.
• Endocardium: a thin inner layer lining the chambers.

The Chambers

• The heart has four chambers:
• Two atria (right and left): thin-walled receiving chambers.
• Two ventricles (right and left): thick-walled pumping chambers.
• The superior poles/bases of the heart contain the right and left atria.

The Valves

• The atrioventricular (AV) valves control blood flow between the atria and ventricles.
  • The right AV valve is known as the tricuspid valve.
  • The left AV valve is known as the mitral valve.
• Semilunar valves (pulmonary and aortic valves) regulate blood flow from the ventricles into the great arteries.
  • Pulmonary valve: controls blood flow from the right ventricle into the pulmonary trunk.
  • Aortic valve: controls blood flow from the left ventricle into the aorta.

Coronary Circulation

• The coronary arteries supply blood to the heart muscle.
• The coronary sinus collects blood from the heart and empties into the right atrium.

The Conduction System

• The cardiac conduction system controls the timing of heart contractions to ensure coordinated function of the heart's chambers.
• The system involves specialized tissues and signaling pathways that generate and transmit electrical impulses.

Explore the intricate functions of the circulatory system, focusing on its key components: the heart, blood vessels, and blood. Understand how these elements work together to transport essential substances throughout the body. Learn about the pulmonary and systemic circuits that play vital roles in blood circulation.