Chapter 23 Circulation  The Circulatory System aids cells to

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Chapter 23 Circulation
 The Circulatory System aids cells to
– receive nutrients, exchange gases, and removes wastes.
– Blood is used to transport these materials using red blood
cells filled with hemoglobin and the liquid part of blood
tissue called plasma
– Blood is in vessels called arteries and veins that are
connected by capillaries. Blood moves away from the
heart in arteries and towards the heart in veins.
© 2012 Pearson Education, Inc.
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Blood passes through the heart of a fish once in
each circuit through the body, an arrangement called
single circulation.
 A single circuit would not supply enough pressure to
move blood through the capillaries of the lungs and
then to the body capillaries of a terrestrial vertebrate.
© 2015 Pearson Education, Inc.
Figure 23.2a
Gill
capillaries
Heart:
Ventricle
Atrium
Body
capillaries
© 2015 Pearson Education, Inc.
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Land vertebrates have a double circulation in
which blood is pumped a second time after it loses
pressure in the lungs.
– The pulmonary circuit carries blood between the heart
and gas exchange tissues in the lungs.
– The systemic circuit carries blood between the heart
and the rest of the body.
© 2015 Pearson Education, Inc.
Figure 23.2b
Figure 23.2B The double
circulation and
three-chambered heart
of an amphibian
Lung and
skin capillaries
Pulmocutaneous
circuit
Atrium
Atrium
Ventricle
Right
Left
Systemic
circuit
Systemic
capillaries
© 2015 Pearson Education, Inc.
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Frogs and other amphibians have a threechambered heart.
– The right atrium receives blood returning from the
systemic capillaries in the body’s organs.
– The ventricle pumps blood to the lungs and skin.
– Because gas exchange occurs both in the lungs and
across the thin, moist skin, this is called a
pulmocutaneous circuit.
© 2015 Pearson Education, Inc.
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 Frogs and other amphibians have a threechambered heart.
– The right atrium receives blood returning from the
systemic capillaries in the body’s organs.
– The ventricle pumps blood to the lungs and skin.
– Because gas exchange occurs both in the lungs and
across the thin, moist skin, this is called a
pulmocutaneous circuit.
© 2015 Pearson Education, Inc.
23.2 EVOLUTION CONNECTION: Vertebrate
cardiovascular systems reflect evolution
 In all birds and mammals, the heart has four
chambers:
– two atria and
– two ventricles.
 The right side of the heart handles only oxygen-poor
blood.
 The left side receives and pumps only oxygen-rich
blood.
© 2015 Pearson Education, Inc.
23.3 The human cardiovascular system illustrates
the double circulation of mammals
 Blood flow through the circulatory system of humans
– drains from the large veins called the superior vena
cava (from the head and arms) or inferior vena cava
(from the lower trunk and legs) into the right atrium, the
heart contracts pushing blood into the right ventricle
through a valve
– moves out to the lungs via the pulmonary artery, which
forms capillaries in alveoli
– returns to the left atrium through the pulmonary vein,
and goes into the left ventricle where it leaves the heart
through a large artery called the aorta.
© 2012 Pearson Education, Inc.
Figure 23.3
Capillaries of head,
chest, and arms
Superior vena cava
Pulmonary artery
Pulmonary artery
Aorta
Pulmonary circuit
Systemic circuit
Lung
capillaries
Pulmonary
vein
Right
atrium
Inferior
vena cava
Right
ventricle
Left
ventricle
Left
atrium
Pulmonary
vein
Aorta
Capillaries of abdominal
region and legs
© 2015 Pearson Education, Inc.
Figure 23.4
To lung
To lung
Left atrium
Right atrium
From lung
From lung
Semilunar
valve
Semilunar
valve
Atrioventricular
(AV) valve
Atrioventricular
(AV) valve
Right
ventricle
Left
ventricle
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