Download Intro to Cardiovascular System

Cardiovascular System
A closed system of the heart and blood vessels
 The function of the cardiovascular system
 TRANSPORTATION
 deliver oxygen
 deliver nutrients
 movement of hormones
 remove carbon dioxide
 remove urea
 remove other waste products
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 Blood: the mechanism for transport of
these materials
 Blood vessels: tubes through which
materials are transported
 Heart: the force that keeps materials
circulating
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The Heart
 Location
 Thorax between the lungs in the inferior
mediastinum
 Orientation
 Pointed apex (tip) directed toward left hip
 Base (where the blood vessels emerge) points
toward right shoulder
 About the size of your fist
 Hollow
 Cone shaped
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The Heart: Coverings
 Pericardium—a double-walled sac
1. Fibrous pericardium is loose and superficial
 for protection
 to hold the heart in place
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The Heart: Coverings
2. Serous pericardium (deep to the fibrous
pericardium)
2 layers
a. Visceral pericardium

Next to heart; also known as the
epicardium
b. Parietal pericardium


Outside layer that lines the inner
surface of the fibrous pericardium
Serous fluid fills the space between the
layers of pericardium
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1. Heart
2. Fibrous
pericardium
3. Parietal layer
of serous
pericardium
4. Visceral layer
of serous
pericardium
5. Pericardial
space
6. Pleural cavity
and lung
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The Heart: Heart Wall
3 layers
 Epicardium (AKA: visceral pericardium)
 Outside layer
 Connective tissue layer
 Myocardium
 Middle layer
 Mostly muscle
 Endocardium
 Inner layer
 Endothelium
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The Heart: Chambers
 Right and left side act as separate pumps
 Four chambers
 Atria (plural)
 Receiving chambers
 Right atrium
 Left atrium
 Ventricles
 Discharging chambers
 Right ventricle
 Left ventricle
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Differences in Right and Left Ventricles
Left ventricle is visibly
more muscular
It is responsible for
pushing the blood out of
the heart and into the
vessel systems that carry
blood to the entire body
Figure 11.4
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The Heart: Septa
Tissue dividing the chambers
Named based on their location
 Interventricular septum
 Separates the two ventricles
 Interatrial septum
 Separates the two atria
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The Heart: Valves
 Allow blood to flow in only one
direction to prevent backflow
 4 valves
 Atrioventricular (AV) valves
between atria and ventricles
1. Bicuspid (AKA:
mitral) valve (left side
of heart)
2. Tricuspid valve (right
side of heart)
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The Heart: Valves
 Semilunar valves
between ventricle and artery
3. Pulmonary semilunar valve
4. Aortic semilunar valve
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The Heart: Valves
 AV valves (Tricuspid/Bicuspid)
 Anchored in place by chordae tendineae (“heart
strings”) which attach to papillary muscle to keep them
from turning inside out
 Open during heart relaxation and closed during
ventricular contraction
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The Heart: Valves
 Semilunar valves
 Closed during heart relaxation but open
during ventricular contraction
 Notice these valves operate opposite of one
another to force a one-way path of blood through
the heart
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2 Main Types of Circulation
1. Systemic circulation
 Blood flows from the left side of the heart
through the body tissues and back to the right
side of the heart
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2 Main Types of Circulation
2. Pulmonary circulation
 Blood flows from the right side of the heart to
the lungs and back to the left side of the heart
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Systemic and Pulmonary Circulations
Figure 11.3
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The Heart: Associated Great Vessels
 Arteries
 Aorta
 Leaves left ventricle
 Pulmonary arteries
 Leave right ventricle
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The Heart: Associated Great Vessels
 Veins
 Superior and inferior venae cavae
 Enter right atrium
 Pulmonary veins (four)
 Enter left atrium
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The Heart: Associated Great Vessels
Figure 11.2c
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Blood Flow Through the Heart
 Superior and inferior venae cavae dump blood
into the right atrium
 From right atrium, through the tricuspid valve,
blood travels to the right ventricle
 From the right ventricle, blood leaves the heart as
it passes through the pulmonary semilunar valve
into the pulmonary trunk
 Pulmonary trunk splits into right and left
pulmonary arteries that carry blood to the lungs
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Blood Flow Through the Heart
 Oxygen is picked up and carbon dioxide is
dropped off by blood in the lungs
 Oxygen-rich blood returns to the heart through
the four pulmonary veins
 Blood enters the left atrium and travels through
the bicuspid valve into the left ventricle
 From the left ventricle, blood leaves the heart via
the aortic semilunar valve and aorta
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings