CARDIOVASCULAR SYSTEM
The cardiovascular system is an organ system that conveys blood through vessels to and from all parts of the
body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes. It includes the heart and
the blood vessels.
HEART
It is approximately the size of your fist
Its primary function is to serve as a muscular pump propelling blood into and through vessels to and from all
parts of the body.
It is suspended in its own membranous sac, the pericardium.
It has four chambers and four valves that regulate blood flow:
Anatomy Function
Chambers that receive blood returning from your body through your
Left and right atria
veins
Left and right ventricles Chambers where blood is pumped to your body through your arteries
The mitral valve controls the flow of oxygen-rich blood from the left
Mitral valve
atrium to the left ventricle
The tricuspid valve controls the flow of oxygen-poor blood from the
Tricuspid valve
right atrium to the right ventricle
The aortic valve controls flow of oxygen-rich blood from the left
Aortic valve
ventricle to the body
The pulmonary valve controls flow of oxygen-poor blood from the
Pulmonary valve
right ventricle to the lungs
, BLOOD VESSELS
Intricate networks of hollow tubes that transport blood throughout the entire body.
Through the process of microcirculation, substances such as oxygen, carbon dioxide, nutrients, and wastes are
exchanged between the blood and the fluid that surrounds cells.
o Microcirculation deals with the circulation of blood from the heart to arterioles (small arteries), to
capillaries, to venules (small veins) and back to the heart.
Structure and Functions of Blood Vessels
Structure Functions
Arteries The walls (outer structure) of arteries contain Transport blood away from the heart;
smooth muscle fibre that contract and relax under
Transport oxygenated blood only (except in the
the instructions of the sympathetic nervous system.
case of the pulmonary artery).
Arterioles Arterioles are tiny branches of arteries that lead to Transport blood from arteries to capillaries;
capillaries. These are also under the control of the
Arterioles are the main regulators of blood flow
sympathetic nervous system, and constrict and
and pressure.
dialate, to regulate blood flow.
Capillaries Capillaries are tiny (extremely narrow) blood Function is to supply tissues with components
vessels, of approximately 5-20 micro-metres of, and carried by, the blood, and also to
(one micro-metre = 0.000001metre) diameter. remove waste from the surrounding cells ... as
There are networks of capillaries in most of the opposed to simply moving the blood around
organs and tissues of the body. These capillaries the body (in the case of other blood vessels);
are supplied with blood by arterioles and drained by Exchange of oxygen, carbon dioxide, water,
venules. Capillary walls are only one cell thick (see salts, etc., between the blood and the
diagram), which permits exchanges of material surrounding body tissues.
between the contents of the capillary and the
surrounding tissue.
Venules Venules are minute vessels that drain blood from Drains blood from capillaries into veins, for
capillaries and into veins. Many venules unite to return to the heart
form a vein.
The cardiovascular system is an organ system that conveys blood through vessels to and from all parts of the
body, carrying nutrients and oxygen to tissues and removing carbon dioxide and other wastes. It includes the heart and
the blood vessels.
HEART
It is approximately the size of your fist
Its primary function is to serve as a muscular pump propelling blood into and through vessels to and from all
parts of the body.
It is suspended in its own membranous sac, the pericardium.
It has four chambers and four valves that regulate blood flow:
Anatomy Function
Chambers that receive blood returning from your body through your
Left and right atria
veins
Left and right ventricles Chambers where blood is pumped to your body through your arteries
The mitral valve controls the flow of oxygen-rich blood from the left
Mitral valve
atrium to the left ventricle
The tricuspid valve controls the flow of oxygen-poor blood from the
Tricuspid valve
right atrium to the right ventricle
The aortic valve controls flow of oxygen-rich blood from the left
Aortic valve
ventricle to the body
The pulmonary valve controls flow of oxygen-poor blood from the
Pulmonary valve
right ventricle to the lungs
, BLOOD VESSELS
Intricate networks of hollow tubes that transport blood throughout the entire body.
Through the process of microcirculation, substances such as oxygen, carbon dioxide, nutrients, and wastes are
exchanged between the blood and the fluid that surrounds cells.
o Microcirculation deals with the circulation of blood from the heart to arterioles (small arteries), to
capillaries, to venules (small veins) and back to the heart.
Structure and Functions of Blood Vessels
Structure Functions
Arteries The walls (outer structure) of arteries contain Transport blood away from the heart;
smooth muscle fibre that contract and relax under
Transport oxygenated blood only (except in the
the instructions of the sympathetic nervous system.
case of the pulmonary artery).
Arterioles Arterioles are tiny branches of arteries that lead to Transport blood from arteries to capillaries;
capillaries. These are also under the control of the
Arterioles are the main regulators of blood flow
sympathetic nervous system, and constrict and
and pressure.
dialate, to regulate blood flow.
Capillaries Capillaries are tiny (extremely narrow) blood Function is to supply tissues with components
vessels, of approximately 5-20 micro-metres of, and carried by, the blood, and also to
(one micro-metre = 0.000001metre) diameter. remove waste from the surrounding cells ... as
There are networks of capillaries in most of the opposed to simply moving the blood around
organs and tissues of the body. These capillaries the body (in the case of other blood vessels);
are supplied with blood by arterioles and drained by Exchange of oxygen, carbon dioxide, water,
venules. Capillary walls are only one cell thick (see salts, etc., between the blood and the
diagram), which permits exchanges of material surrounding body tissues.
between the contents of the capillary and the
surrounding tissue.
Venules Venules are minute vessels that drain blood from Drains blood from capillaries into veins, for
capillaries and into veins. Many venules unite to return to the heart
form a vein.
