Figure 18.9
The heart is a double pump, each side supplying
its own circuit.
Right
atrium
Aorta
To body
To heart
To heart
To lungs
Mitral
valve
Left
ventricle
Left
atrium
Left
atrium
Aorta
Left
ventricle
Four
pulmonary
veins
Right
ventricle
Superior vena cava
(SVC)
Inferior vena cava
(IVC)
Coronary sinus
Right
atrium
Pulmonary
trunk
Pulmonary
veins
Pulmonary
arteries
Aortic
semilunar
valve
Tricuspid
valve
Tricuspid
valve
Pulmonary
trunk
Right
ventricle
Pulmonary
semilunar
valve
Pulmonary
semilunar valve
IVC
SVC
Oxygen-poor blood
Oxygen-rich blood
Mitral
valve
Aortic
semilunar valve
Coronary
sinus
Both sides of the heart pump at the same time, but let’s follow one
spurt of blood all the way through the system.
Oxygen-poor blood is carried
in two pulmonary arteries to
the lungs
(pulmonary circuit)
to be oxygenated.
Oxygen-poor blood
returns from the body
tissues back to the heart.
Oxygen-rich blood is
delivered to the body
tissues
(systemic circuit)
.
Oxygen-rich blood returns
to the heart via the four
pulmonary veins.
Pulmonary
capillaries
Systemic
capillaries
FOCUS
Blood Flow Through the Heart
669
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