The heart is a specialund muscle that serves as a pump. This pump
is divided into four chambers connected by tiny doors called valve
The chambers work to keep the blood flowing round the body in
a circle.
At the end of each circuit, veins carry the blood to the right,
the first of the four chambers 25 oxygen by then is used up and
is on its way back to the long to pick up a fresh supply and to give
up the carbon dioxide it has accumulated. From the right atrium
the blood flows through the tricuspid valve into the second chamber,
the right ventricle. The right ventricle contracts when it is filled
pushing the blood through the pulmonary artery, which leads to the
lungs- in the lungs the blood gives up its carbon dioxide and picka
up fresh oxygen. Then it travels to the third chamber the left atrium
When this chamber is filled it forces the blood through the valve to
the left ventricle. From here it is pushed into a big blood vessel
called aorta and sent round the body by way of arteries.
Heart disease can result from any damage to the heart muscle, the
valves or the Pacemaker. If the muscle is damaged, the heart is
unable to pump properly. If the valves are damaged blood cannot
flow normally and easily from one chamber to another, and if the
pacemaker is defective, the contractions of the chambers will
become un-coordinated.
Until the twentieth century, few doctors dared to touch the heart
In 1953 all this changed after twenty years of work, Dr. John
Gibbon in the USA had developed a machine that could take over
temporarily from the heart and lungs. Blood could be routed through
the machine bypassing the heart so that surgeons could work inside
it and see what they were doing. The era of open heart surgery
had begun.
104
Answers
Answer:
The heart
The heart is made of specialized cardiac muscle tissue that allows it to act as a pump within the circulatory system.
The human heart is divided into four chambers. There are one atrium and one ventricle on each side of the heart. The atria receive blood and the ventricles pump blood.
The human circulatory system consists of several circuits:
The pulmonary circuit provides blood flow between the heart and lungs.
The systemic circuit allows blood to flow to and from the rest of the body.
The coronary circuit strictly provides blood to the heart (not pictured in the figure below).
Diagram showing the flow of blood from the heart to the rest of the human body.
Diagram showing the flow of blood from the heart to the rest of the human body.
Blood and blood vessels
Blood from the heart is pumped throughout the body using blood vessels. Arteries carry blood away from the heart and into capillaries, providing oxygen (and other nutrients) to tissue and cells. Once oxygen is removed, the blood travels back to the lungs, where it is reoxygenated and returned by veins to the heart.
Diagram labeling the major arteries (red) and veins (blue) in the human body
Diagram labeling the major arteries (red) and veins (blue) in the human body
The main artery of the systemic circuit is the aorta which branches out into other arteries, carrying blood to different parts of the body.