The Circulatory System
~Notes~
1. What is the Circulatory System?:
The cardiovascular system, sometimes referred to as the circulatory system, is in charge of distributing
hormones, oxygen, nutrients, and blood throughout the body. It is comprised of blood, blood arteries,
and the heart.
Fun Fact: Your heart pumps around 5 liters (1.3 gallons) of blood every minute, which is about 7,200
liters (1,900 gallons) a day!
Structure:
Chambers~
● Atria (Singular: Atrium): The upper chambers of the heart. There are two atria – the right
atrium and the left atrium.
○ Right Atrium: Receives deoxygenated blood from the body through the superior and
inferior vena cava.
○ Left Atrium: Receives oxygenated blood from the lungs through the pulmonary veins.
● Ventricles: The lower chambers of the heart. There are two ventricles – the right ventricle and
the left ventricle.
○ Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary artery.
○ Left Ventricle: Pumps oxygenated blood to the rest of the body via the aorta. The left
ventricle has the thickest walls to generate enough force to pump blood throughout
the body.
Heart Valves~
● Tricuspid Valve: Located between the right atrium and right ventricle. It prevents the backflow
of blood into the right atrium when the right ventricle contracts.
● Pulmonary Valve: Located between the right ventricle and the pulmonary artery. It prevents
the backflow of blood into the right ventricle after it has been pumped to the lungs.
● Mitral Valve: Also known as the bicuspid valve, located between the left atrium and left
ventricle. It prevents the backflow of blood into the left atrium when the left ventricle
contracts.
● Aortic Valve: Located between the left ventricle and the aorta. It prevents the backflow of
blood into the left ventricle after it has been pumped into the aorta.
Walls and Layers~
● Endocardium: The deepest layer, which covers the heart's valves and lines the chambers.
~Notes~
1. What is the Circulatory System?:
The cardiovascular system, sometimes referred to as the circulatory system, is in charge of distributing
hormones, oxygen, nutrients, and blood throughout the body. It is comprised of blood, blood arteries,
and the heart.
Fun Fact: Your heart pumps around 5 liters (1.3 gallons) of blood every minute, which is about 7,200
liters (1,900 gallons) a day!
Structure:
Chambers~
● Atria (Singular: Atrium): The upper chambers of the heart. There are two atria – the right
atrium and the left atrium.
○ Right Atrium: Receives deoxygenated blood from the body through the superior and
inferior vena cava.
○ Left Atrium: Receives oxygenated blood from the lungs through the pulmonary veins.
● Ventricles: The lower chambers of the heart. There are two ventricles – the right ventricle and
the left ventricle.
○ Right Ventricle: Pumps deoxygenated blood to the lungs via the pulmonary artery.
○ Left Ventricle: Pumps oxygenated blood to the rest of the body via the aorta. The left
ventricle has the thickest walls to generate enough force to pump blood throughout
the body.
Heart Valves~
● Tricuspid Valve: Located between the right atrium and right ventricle. It prevents the backflow
of blood into the right atrium when the right ventricle contracts.
● Pulmonary Valve: Located between the right ventricle and the pulmonary artery. It prevents
the backflow of blood into the right ventricle after it has been pumped to the lungs.
● Mitral Valve: Also known as the bicuspid valve, located between the left atrium and left
ventricle. It prevents the backflow of blood into the left atrium when the left ventricle
contracts.
● Aortic Valve: Located between the left ventricle and the aorta. It prevents the backflow of
blood into the left ventricle after it has been pumped into the aorta.
Walls and Layers~
● Endocardium: The deepest layer, which covers the heart's valves and lines the chambers.
