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Introduction
• Cardiovascular system: heart, blood, and
blood vessels
• Cardiac muscle
– Makes up bulk of heart
– Provides force to pump blood
• Function: transports blood
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The Anatomy of the Heart
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Introduction
• Located in the mediastinum
• Surrounded by pericardial sac, which has two following
parts:
– Fibrous pericardium: outer layer, which is made of tough
fibrous connective tissue and connects to the large blood
vessels that enter and exit the heart.
– Serous pericardium: inner layer,thin and delicate.
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Introduction
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The Layers of the Heart Wall
• Epicardium/visceral pericardium: outermost layer,
thin, transparent layer.
• Pericardial cavity: separates epicardium and serous
pericardium. This cavity contains a watery fluid called pericardial
fluid, which reduces friction and erosion of tissue between these
membranes as the heart expands and contracts during a cardiac
cycle.
• If an inflammation of the inner most layer of pericardial sac
develops, it is known as pericarditis.
• Myocardium: middle muscular layer, layer of cardiac muscle
tissue. It is involuntary, striated, and branched. This layer is
arranged in interlacing bundles and is the layer responsible for
contraction of the heart.
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• Endocardium: lines the third or innermost layer of
the heart .Thin layer of connective tissue penetrated by
tiny blood vessels and bundles of smooth muscle.It
covers the valves of the heart and the chordae
tendineae of the valves.
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The Layers of the Heart Wall
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The Layers of the Heart Wall
(cont’d.)
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The Chambers of the Heart
• Upper chambers: right and left atria .Each atrium has an external
appendage called an auricle, names because of its similarity to the
ear of a dog. Auricle increases the volume of the atrium. The two
atria are separated from each other by an internal inter-atrial
septum.
• Lower chambers: right and left ventricles. They are internally
separated from each other by interventricular septum. The irregular
ridges and folds of the myocardium of the ventricles are called
trabeculae carneae.
• Chambers separated internally by septum
• External separations by:
– Coronary sulcus: separates atria and ventricles
– Anterior and posterior Interventricular sulci: separate ventricles
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The Great Vessels of the Heart
• Right atrium receives blood from all parts of the body
except the lungs. It receives this blood through three
veins: superior/anterior vena cava( brings blood from
upper parts of the body, head, neck, and arms), inferior
vena cava/posterior vena cava( brings blood from the
lower parts of the body, legs and abdomens)
• Coronary sinus: drains blood from most of the vessels
that supply the walls of the heart with blood.
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The Great Vessels of the Heart
(cont’d.)
• The right ventricle pumps the blood into pulmonary trunk which
splits into the right pulmonary artery and the left pulmonary artery,
which carry the blood to the lungs.
– They carry deoxygenated blood to lungs.
• Pulmonary veins (four): return oxygenated blood to heart/left atrium.
Then the blood is squeezed into the left ventricle.
• Ascending aorta: carries oxygenated blood out to body, and to the
coronary arteries ( which supply the walls of the heart with
oxygenated blood), the arch of the aorta( which sends arteries to
upper parts of the body). Descending thoracic aorta which becomes
abdominal aorta.
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The Valves of the Heart
• Atrioventricular
– Tricuspid (three cusps)
• Between right atrium and right ventricle
– Bicuspid (two cusps)/atrioventricular
valve/mitral valve
• Between left atrium and right ventricle
– Cusps attach to ventricles by chordae
tendineae
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The Valves of the Heart (cont’d.)
• Semilunar valves
– Pulmonary semilunar valve
• Right ventricle
• Pulmonary trunk exits the heart
– Aortic semilunar valve
• Left ventricle
• Ascending aorta leaves the heart
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The Valves of the Heart (cont’d.)
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Blood Flow through the Heart
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Blood Flow through the Heart
(cont’d.)
• Deoxygenated blood enters right atrium via
superior/inferior vena cava and coronary sinus.
• Deoxygenated blood returns from body to right atrium
• Sent to right ventricle passing tricuspid valve, which
pumps blood to lungs via pulmonary trunk passing the
pulmonary semilunar valve.
• Left/right pulmonary arteries go to lungs to get
oxygenated and return to heart in left atrium via left/right
pulmonary veins.
• Oxygenated blood returns to left atrium
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Blood Flow through the Heart
(cont’d.)
• Sent to left ventricle passing the bicuspid/mitral valve.
• Left ventricle sends blood to the body via the ascending
aorta passing the aortic semilunar valve.
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Blood Flow through the Heart
(cont’d.)
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The Conduction System of the
Heart
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The Conduction System of the
Heart (cont’d.)
• Sinoatrial (SA) node: pacemaker; initiates
impulse 
• Atrioventricular (AV) node: sends impulse
to AV bundle 
• Bundle of His: sends impulses to both
sides of system 
• Purkinje’s fibers: send impulse to
myocardial cells
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The Conduction System of the
Heart (cont’d.)
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A Cardiac Cycle
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A Cardiac Cycle (cont’d.)
• One cycle
– Atria contract / ventricles relax
– Ventricles contract / atria relax
• Systole: contraction phase
• Diastole: relaxation phase
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Some Major Blood Circulatory
Routes
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Some Major Blood Circulatory
Routes (cont’d.)
• Systemic circulation
– All blood leaving left ventricle (oxygenated)
– All blood returning to right atrium
(deoxygenated)
– Pulmonary: blood flow to lungs for gas
exchange
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Anatomy of Blood Vessels
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Anatomy of Blood Vessels (cont’d.)
• Arteries and veins have three layers
– Tunica intima: innermost layers
– Tunica media: middle layer
– Tunica adventitia: outer layer
• Lumen: blood vessel cavity
• Anastomosis: junction of blood vessels
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Anatomy of Blood Vessels (cont’d.)
• Arteries: thicker and stronger than veins
• Arterioles: small arteries attach to
capillaries
• Capillaries: gas nutrient and waste
exchange
• Venules: connect capillaries to veins
• Veins: less elastic than arteries, contain
valves
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Anatomy of Blood Vessels (cont’d.)
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Major Arteries and Veins of
the Body
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Ascending Aorta Branches
• Right and left coronary arteries branch off
and supply the heart
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Aortic Arch Branches
• 1st branch: brachiocephalic artery
– Right common carotid artery and right
subclavian artery
• 2nd branch: left common carotid artery
– Left internal carotid artery and left external
carotid artery
• 3rd branch: left subclavian artery
– Vertebral artery, axillary artery, brachial artery,
and radial and ulnar arteries
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Thoracic Aorta Branches
•
•
•
•
10 pairs of intercostal arteries
Bronchial arteries
Esophageal arteries
Phrenic arteries
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Abdominal Aorta Branches
•
•
•
•
•
•
Celiac trunk
Superior and inferior mesenteric arteries
Right and left renal arteries
Right and left gonadal arteries
Lumbar arteries
Right and left common iliac artery
– Femoral artery
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Abdominal Aorta Branches (cont’d.)
• Veins
– Found closer to surface than arteries
– Converge with
• Superior vena cava
• Inferior vena cava
– Veins are often named identically to arteries
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Veins Merging into the Superior
Vena Cava
• Radial and ulnar veins form brachial vein
– Empties into axillary vein
•
•
•
•
•
Cephalic vein
Basilic vein
Subclavian vein
Vertebral vein
Internal jugular vein
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Veins Merging into the Superior
Vena Cava (cont’d.)
• Right and left brachiocephalic veins
• Azygos vein
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Veins Merging into the Inferior
Vena Cava
• Anterior and posterior tibial veins
• Peroneal vein
• Popliteal/femoral veins
– External iliac vein
• Great saphenous veins
• Right and left common iliac veins
• Right and left gonadal veins
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Veins Merging into the Inferior
Vena Cava (cont’d.)
• Right and left renal veins
• Hepatic portal vein
• Right and left hepatic veins
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Summary
• Named the layers of the heart wall
• Named the chambers and valves of the
heart
• Described blood flow through the heart
• Described the conduction system of the
heart
• Discussed the stages of the cardiac cycle
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Summary (cont’d.)
• Compared the anatomy of a vein, artery
and capillary
• Named the major blood circulatory routes
and blood vessels
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