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I. Anatomy of the Heart
A. Heart Wall
1. Location – Mediastinum
2. Gross Anatomy
a. Base
b. Apex
3. Pericardium – Pericardial Sac
a. Fibrous Pericardium
b. Serous Pericardium
1) Parietal Pericardium
2) Visceral Pericardium – Epicardium
c. Pericardial Cavity
1) Serous Fluid
d. Clinical Application: Pericarditis
4. Layers
a. Epicardium
b. Myocardium
1) Cardiocytes (Cardiac muscle cells)
a. Uninucleated and Branched
b. Intercalated discs
1) Cardiac (Fibrous) Skeleton of the Heart
c. Endocardium
1) Continuous with Endothelium of vessels
B. External and Internal Anatomy of the Heart
1. Atria – Receiving chambers
a. Right Atrium
1) Receives Blood from
a) Superior Vena Cava
b) Inferior Vena Cava
c) Coronary Sinus
b. Left Atrium
1) Receives Blood from
a) Pulmonary Veins* - Oxygenated
blood - Usually 4 vessels (3-5)
2. Ventricles – Pumping chambers
a. Right Ventricle
1) Pumps blood for Pulmonary Circuit
a) Pulmonary Trunk
1] Right and Left Pulmonary
Arteries* - Deoxygenated blood
b. Left Ventricle
1) Pumps blood for Systemic Circuit
a) Aorta
3. External Anatomy
a. Auricle
b. Coronary Sulcus (Atrioventricular Groove)
c. Anterior Interventricular Sulcus
d. Posterior Interventricular Sulcus
e. Ligamentum arteriosum – Adult relic
1) Ductus arteriosus – Fetal bypass
4. Internal Anatomy
a. Interatrial Septum
1) Fossa ovalis – Adult relic
a) Foramen ovale – Fetal bypass
b. Interventricular Septum
c. Pectinate Muscles
d. Trabeculae carneae
e. Moderator band (Septomarginal band)
1) Passes electrical signals from septum to
muscles in the right ventricle
f. Heart Valves
1) Atrioventricular (AV) Valves
a) Tricuspid Valve
b) Bicuspid Valve (Mitral Valve)
1] Clinical Application:
Mitral Valve Prolapse
c) Chordae tendineae
d) Papillary muscles
2) Semilunar Valves
a) Aortic Semilunar Valve
b) Pulmonary Semilunar Valve
C. Coronary Circulation
1. Right Coronary Artery (RCA)
a. Located in Coronary Sulcus (Atrioventricular Groove)
b. Branches to
1) Atrial arteries
2) Marginal Arteries
a) Right Ventricle
3) Posterior Interventricular Branch
a) Located in Posterior Interventricular
Sulcus
b) Supplies Right and Left Ventricles
and Interventricular Septum
2. Left Coronary Artery (LCA)
a. Located in Coronary Sulcus (Atrioventricular Groove)
1) Branches to
a) Anterior Interventricular Branch
1] Located in Anterior
Interventricular Sulcus
2] Supplies Right and Left
Ventricles and Interventricular
Septum
a) Circumflex Artery (Branch)
1] Located in Coronary Sulcus
2] Supplies Left ventricle and
Left Atrium
3] Gives off Marginal arteries to
Left Ventricle
3. Coronary Sinus
a. Empties into Right Atrium
b. Principal Tributaries
1) Great Cardiac Vein
a) Anterior Drainage
2) Middle Cardiac Vein
a) Posterior Drainage of RCA
3) Small Cardiac Vein
a) Drain Right Marginal Region
4) Posterior Cardiac Vein
a) Posterior Drainage of LCA
4. Anterior Cardiac Veins
a. Empty into Right Atrium Directly
5. Anastomoses
a. Arterial Anastomosis
6. Clinical Application: Myocardial Infarction (MI)
D. Conducting System
1. Nodal cells
2. Sinoatrial (SA) node – Intrinsic Pacemaker
a. Located inferior to where Superior Vena Cava
enters Right Atrium
b. Self-excites faster than other nodal cells
3. Atrioventricular (AV) node
a. Located in the lower medial floor of right atrium
b. Slows Conduction Velocity (100 msec)
1) Allows time for Atria to contract
4. Atrioventricular (AV) bundle – Bundle of His
a. Located in the Interventricular Septum
b. Conduction Velocity increases to highest speed
5. Right and Left Branches
a. Moderator band (from Right Branch) conducts
directly to Papillary muscle
6. Purkinje fibers
a. Within the muscle bundles of the ventricular walls
b. Distributes electrical impulse to cardiocytes
1) Ventricles contract