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CARDIOVASCULAR SYSTEM ANATOMY
The cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of
blood that the blood vessels transport. Responsible for transporting oxygen, nutrients,
hormones, and cellular waste products throughout the body, the cardiovascular system is
powered by the body’s hardest-working organ — the heart, which is only about the size of a
closed fist.
o The Heart
The heart is a muscular pumping organ located medial to the lungs along the body’s midline
in the thoracic region. The bottom tip of the heart, known as its apex, is turned to the left, so
that about 2/3 of the heart is located on the body’s left side with the other 1/3 on right. The
top of the heart, known as the heart’s base, connects to the great blood vessels of the body:
the aorta, vena cava, pulmonary trunk, and pulmonary veins.
o Circulatory Loops
There are 2 primary circulatory loops in the human body: the pulmonary circulation loop and the
systemic circulation loop.
1. Pulmonary circulation transports deoxygenated blood from the right side of the heart to
the lungs, where the blood picks up oxygen and returns to the left side of the heart. The
pumping chambers of the heart that support the pulmonary circulation loop are the right
atrium and right ventricle.
2. Systemic circulation carries highly oxygenated blood from the left side of the heart to all
of the tissues of the body (with the exception of the heart and lungs). Systemic circulation
removes wastes from body tissues and returns deoxygenated blood to the right side of
the heart. The left atrium and left ventricle of the heart are the pumping chambers for the
systemic circulation loop.
o Blood Vessels
Blood vessels are the body’s highways that allow blood to flow quickly and efficiently from the
heart to every region of the body and back again. The size of blood vessels corresponds with
the amount of blood that passes through the vessel. All blood vessels contain a hollow area
called the lumen through which blood is able to flow. Around the lumen is the wall of the vessel,
which may be thin in the case of capillaries or very thick in the case of arteries. All blood vessels
are lined with a thin layer of simple squamous epithelium known as the endothelium that keeps
blood cells inside of the blood vessels and prevents clots from forming. The endothelium lines
the entire circulatory system, all the way to the interior of the heart, where it is called the
endocardium. There are three major types of blood vessels: arteries, capillaries and veins.
Blood vessels are often named after either the region of the body through which they carry
blood or for nearby structures. For example, the brachiocephalic artery carries blood into the
brachial (arm) and cephalic (head) regions. One of its branches, the subclavian artery, runs
CARDIOVASCULAR SYSTEM ANATOMY
The cardiovascular system consists of the heart, blood vessels, and the approximately 5 liters of
blood that the blood vessels transport. Responsible for transporting oxygen, nutrients,
hormones, and cellular waste products throughout the body, the cardiovascular system is
powered by the body’s hardest-working organ — the heart, which is only about the size of a
closed fist.
o The Heart
The heart is a muscular pumping organ located medial to the lungs along the body’s midline
in the thoracic region. The bottom tip of the heart, known as its apex, is turned to the left, so
that about 2/3 of the heart is located on the body’s left side with the other 1/3 on right. The
top of the heart, known as the heart’s base, connects to the great blood vessels of the body:
the aorta, vena cava, pulmonary trunk, and pulmonary veins.
o Circulatory Loops
There are 2 primary circulatory loops in the human body: the pulmonary circulation loop and the
systemic circulation loop.
1. Pulmonary circulation transports deoxygenated blood from the right side of the heart to
the lungs, where the blood picks up oxygen and returns to the left side of the heart. The
pumping chambers of the heart that support the pulmonary circulation loop are the right
atrium and right ventricle.
2. Systemic circulation carries highly oxygenated blood from the left side of the heart to all
of the tissues of the body (with the exception of the heart and lungs). Systemic circulation
removes wastes from body tissues and returns deoxygenated blood to the right side of
the heart. The left atrium and left ventricle of the heart are the pumping chambers for the
systemic circulation loop.
o Blood Vessels
Blood vessels are the body’s highways that allow blood to flow quickly and efficiently from the
heart to every region of the body and back again. The size of blood vessels corresponds with
the amount of blood that passes through the vessel. All blood vessels contain a hollow area
called the lumen through which blood is able to flow. Around the lumen is the wall of the vessel,
which may be thin in the case of capillaries or very thick in the case of arteries. All blood vessels
are lined with a thin layer of simple squamous epithelium known as the endothelium that keeps
blood cells inside of the blood vessels and prevents clots from forming. The endothelium lines
the entire circulatory system, all the way to the interior of the heart, where it is called the
endocardium. There are three major types of blood vessels: arteries, capillaries and veins.
Blood vessels are often named after either the region of the body through which they carry
blood or for nearby structures. For example, the brachiocephalic artery carries blood into the
brachial (arm) and cephalic (head) regions. One of its branches, the subclavian artery, runs
