Download Cardiovascular System

Cardiovascular System
Cardiovascular System - Function
The cardiovascular system transports, from one part of the body to
another: nutrients, oxygen, ions, proteins, hormones and other signaling
molecules, as well as waste products, including carbon dioxide. This
system also helps to maintain homeostasis of fluid volume, pH, and
temperature.
Cardiovascular System - Organs
The primary components of the cardiovascular system are blood, the
heart, and the vessels of the circulatory system, which work together to
transport nutrients, wastes, and gases to every cell in the body.
The blood that is circulated throughout the body contains two main
components:
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•
contains water, electrolytes, glucose, proteins (including
enzymes, hormones, and blood clotting factors) and metabolic
wastes
Formed elements or blood cells
Plasma
There are three types of formed elements:
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•
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transport oxygen and carbon dioxide.
White blood cells fight infection by attacking foreign cells, and clear
old or diseased cells.
Platelets are important for hemostasis (not to be confused with
homeostasis); hemostasis is our ability to stop bleeding after
vascular injury (injury to blood vessels).
Red blood cells
The blood functions to transport molecules and blood cells and
contributes to the maintenance of pH balance. Blood cells are formed in
the red bone marrow.
The heart is divided into four chambers. The two lower chambers, called
ventricles, force blood out into the arteries. The two upper chambers of
the heart, called atria, receive blood returning from the veins. The heart
contracts as a unit, both atria (named right and left) contract together to
move blood into the ventricles and then both ventricles contract at the
same time to move blood out of the heart into the pulmonary artery and
the aorta.
The cardiovascular system is divided into two functional subsystems.
• The systemic circuit transports blood and its components to the body.
• The pulmonary circuit transports blood and its components between
the heart and the lungs.
Arteries of the systemic circuit (also known as the systemic circulatory
circuit) carry oxygenated blood from your heart to provide oxygen and
nutrients dissolved in the blood to every cell in your body. When blood
leaves the left ventricle it first enters the aorta, the largest artery in the
human body. Arteries gradually branch into smaller and more
numerous arterioles which then supply blood to the smallest vessels,
termed capillaries. It is estimated that your body contains
approximately 60,000 miles of capillaries, that is enough to encircle
earth three times! Capillaries allow the exchange of oxygen, nutrients
and waste between the blood and tissue cells. After waste has been
picked up, blood is moved through vessels of increasing size venules into
the larger veins. Veins return oxygen-poor blood back to the heart,
where the blood is passed to the pulmonary circuit to the lungs to pick
up oxygen.
The pulmonary artery (part of the pulmonary circuit) carries oxygen-poor
blood from the right ventricle of the heart to the lungs for oxygenation
and removal of carbon dioxide. The pulmonary veins carry oxygenated
blood from the lungs to the left side of the heart.
Without this system in place that involves both the pumping of the heart
to squeeze blood out, and the network of vessels to distribute the
pumped blood, the cells of your body would not have an adequate
supply of nutrients and oxygen.
Cardiovascular System - Anatomy and Direction
The heart lies medial to the lungs, anterior to the spinal cord, posterior
to the sternum, and superior to the diaphragm. The heart is divided into
four chambers. The two lower chambers, called ventricles, force blood
out into the arteries. The two upper chambers of the heart, called atria,
receive blood returning from the veins.