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The Cardiovascular System
Chapter 13
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Introduction
• Cardiovascular system
distributes blood
– Pump (heart)
– Distribution areas (capillaries)
• Heart has 4 compartments
– 2 receive blood (atria)
– 2 pump blood out (ventricles)
– Vessels
• Veins return blood to the heart
• Arteries take blood away from
the heart
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Superficial Anatomy of the Heart
• Atria = “entrance ways”
– Thin-walled
– Upper chambers
• Ventricles = “hollow
spaces”
– Thick, muscular
• Apex points down & tips
slightly to the left
• Base is superior
– Great vessels attach
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Coverings of the Heart
• Pericardium =
“around the heart”
– Visceral
pericardium =
epicardium
– Parietal
pericardium
– Pericardial space
contains
pericardial fluid
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Internal Anatomy of the Heart
• Chambers of the
heart
– Right & left atrium
• Separated by the
interatrial septum
– Right & left ventricle
• Separated by the
interventricular
septum
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Structure of the Heart Wall
• Epicardium = “upon
the heart” = visceral
pericardium
– Dense fibrous
connective tissue
• Myocardium is the
middle layer
– Cardiac muscle
• Endocardium =
“inside the heart”
– Simple squamous
epithelium
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Great Vessels
• Superior & inferior
vena cava
– Return blood from
body to right atrium
• Coronary Sinus
– Returns blood from
heart wall to right
atrium
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Great Vessels
• Pulmonary veins
– Return blood
(oxygenated) from
lungs to left atrium
• Aorta
– Takes blood from left
ventricle to body
• Pulmonary artery
– Takes blood
(deoxygenated) from
right ventricle to
lungs
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Valves of the Heart
• Atrioventricular (AV)
valves separate the atria
from the ventricles
– Tricuspid valve – right
– Bicuspid valve (mitral)
– left
• Semilunar valves
separate the ventricles
from the great vessels
– Pulmonary semilunar
valve
– Aortic semilunar valve
• Heart sounds
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Valves of the Heart (Ventricular Diastole)
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Valves of the Heart (Ventricular Systole)
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Coronary Circulation
• Vessels that supply the myocardium itself
– Right coronary artery
– Left coronary artery
– Cardiac veins
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Cast of Coronary Vessels
Human Anatomy, 3rd edition
Prentice Hall, © 2001
The Cardiac Cycle
• Contraction pattern of
the myocardium
– Determined by the
conduction system
– Systole = contraction
– Diastole = relaxation
• Both atria contract
• Both ventricles contract
• Atria alternate with
ventricles
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Conduction System of the Heart
• The average heart rate is 72 beats/min.
• Depolarization stimulates contraction
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Conducting System of the Heart
• Depolarization begins in the sinoatrial (SA) node
– Pacemaker
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Conduction System of the Heart
•Depolarization spreads through atria, atria contract
Conducting System of the Heart
• Atrioventricular (AV node) depolarizes
• Depolarization travels down the AV bundle (bundle
of His)
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Conducting System of the Heart
• Depolarization spreads up the ventricular walls
via Purkinje fibers.
– Ventricles contract
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Electrocardiogram
– ECG = a recording of electrical events in the
heart
• P wave = atrial depolarization
• QRS wave = ventricular depolarization
• T wave = ventricular repolarization
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Electrocardiogram
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Electrocardiogram
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Disorders
• Abnormal heart rates
– Bradycardia
– Tachycardia
– Fibrillation
• Angina pectoris
• Myocardial infarction
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Blood Vessels
Human Anatomy, 3rd edition
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Functions of Blood Vessels
• Carry blood away from the heart - arteries
• Transport blood to tissues - capillaries
• Return blood to the heart – veins
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Walls of Blood Vessels
• 3 layers
– Inner layer is endothelium = tunica intima
• Simple squamous epithelium
– Middle layer = tunica media
• Smooth muscle
– Outer layer = tunica externa
• Dense fibrous connective tissue
Human Anatomy, 3rd edition
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Atherosclerosis
Human Anatomy, 3rd edition
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Arteries
• Elastic arteries large arteries
• Muscular arteries
- medium-sized
arteries
• Arterioles - very
small
– Capable of
vasoconstriction
and vasodilation
Human Anatomy, 3rd edition
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Systemic Arterial System
Human Anatomy, 3rd edition
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Major Arteries of the Trunk
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Arteries of the Chest and Upper Extremity
Human Anatomy, 3rd edition
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Capillaries
• All blood-tissue
exchange occurs
here
• Tissue = tunica
intima only
• Three types
– Continuous
– Fenestrated
– Sinusoids
Human Anatomy, 3rd edition
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Capillary Bed with Precapillary Sphincters
Human Anatomy, 3rd edition
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Veins
• Venules
– Very small
– Contain only tunica
intima and tunica
externa
• Medium-sized veins
and large veins
– Contain same 3 layers
as arteries
– Tunica media thinner
– Tuna externa - thickest
layer
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Veins with Valves
• Some veins contain valves – prevent blood
from flowing backwards
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Varicose Veins
•
www.sirweb.org/patPub/varicoseVeinMain.shtml
Human Anatomy, 3rd edition
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www.veinhelp.com/varicoseVeins.htm
Systemic Venous System
Human Anatomy, 3rd edition
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Venous System of the Trunk and Upper Limb
Human Anatomy, 3rd edition
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Blood Flow
– Blood flows because of different pressures in
the system
• Mean pressure in aorta = 100 mmHg
– Pressure decreases continuously through
arterial and venous system
•
•
•
•
•
•
Arteries = 100 – 40 mmHg
Arterioles = 40 – 25 mmHg
Capillaries = 25 – 12 mmHg
Venules = 12 – 8 mmHg
Veins = 8 – 5 mmHg
Vena cava = 2 mmHg
Human Anatomy, 3rd edition
Prentice Hall, © 2001
Blood Pressure
– Definition – force exerted by blood on the wall
of any blood vessel
– Clinical use – refers to pressure in the arteries
• Ventricles contract (systole)
– Arterial pressure rises
– Systolic pressure
• Ventricles relax (diastole)
– Arterial pressure drops
– Diastolic pressure
• Average blood pressure
– 120/80 (young male)
– 110/70 (young female)
– Hypertension
Human Anatomy, 3rd edition
Prentice Hall, © 2001