Circulatory System I

Circulatory System I

• The circulatory system comprises the heart, blood vessels, and blood.
• The cardiovascular system is a component focused on the heart and blood vessels.
• The circulatory system transports substances throughout the body via blood.
• Blood serves as the liquid medium for transporting various materials.
• Blood vessels direct blood flow to specific destinations.
• The heart functions as the pump, maintaining blood flow.
• Without valves, blood flow would require more effort.

Functions of the Circulatory System

• The circulatory system's role involves the heart, blood vessels, and blood.
• The term cardiovascular system specifically refers to the heart and blood vessels.
• The circulatory system is essential for transporting substances to various locations within the body.

The Pulmonary and Systemic Circuits

• The cardiovascular system consists of two main divisions: pulmonary and systemic.
• The pulmonary circuit carries blood to the lungs for gas exchange, then returns it to the heart.
• The systemic circuit circulates blood throughout the body, supplying oxygen and removing waste.
• The systemic circuit includes blood flow to organs and parts of the lungs.

The Pathway of Blood Flow

• Blood flow from the body's right side enters the lungs to gain oxygen.
• The pathway from 4 to 6 is the pulmonary circuit.
• From 9 to 11 is the systemic circuit.
• Violet arrows define deoxygenated blood; orange, oxygenated blood.

The Heart Wall

• The heart wall has three layers: the epicardium (outer layer), myocardium (middle, muscular layer), and endocardium (inner layer).
• The epicardium covers the heart's external surface.
• The myocardium is the muscular center layer.
• The endocardium lines the inner surfaces of the heart's chambers.

The Chambers of the Heart

• The heart possesses four chambers (two atria and two ventricles).
• The right and left atria collect blood returning to the heart.
• The right and left ventricles pump blood out of the heart.
• The superior and inferior vena cavae are primary veins bringing blood to the heart.

The Valves

• The atrioventricular (AV) valves regulate blood flow between the atria and ventricles.
• The right AV valve is also known as the tricuspid valve.
• The left AV valve is also known as the mitral valve.
• Semilunar valves (pulmonary and aortic) regulate blood flow from the ventricles to the arteries.
• The pulmonary valve is between the right ventricle and pulmonary trunk.
• The aortic valve is between the left ventricle and the aorta.

Coronary Circulation

• The coronary arteries supply oxygenated blood to the heart muscle.
• The coronary sinus is a vein that collects blood from the heart muscle.
• Blood from the heart muscle returns blood to the right atrium.

Position, Size, and Shape of the Heart

• The heart lies in the mediastinum, between the lungs, behind the sternum.
• The heart's base is its superior part, where major vessels attach.
• The heart's blunt, pointed end is called the apex.

The Pericardium

• The heart is enclosed in a double-walled sac called the pericardium.
• The outer layer is the pericardial sac and layer of fibrous connective tissue.
• The inner layer of serous tissue is the visceral pericardium, also known as the epicardium.
• The space between the layers is the pericardial cavity filled with serous fluid.

The Conduction System

• The cardiac conduction system controls heart rate and timing.
• The sinoatrial (SA) node acts as the heart's natural pacemaker.
• Atrial and ventricular contraction are coordinated through the conduction system pathways.
• The AV node, AV bundle, and Purkinje fibers relay signals for coordinated contractions.

This quiz covers key concepts related to the circulatory system, including the heart, blood vessels, and their functions. Explore the roles of the cardiovascular system in transporting essential materials throughout the body. Test your understanding of the pulmonary and systemic circuits and their significance in circulation.