Lecture 13 : The Cardiovascular Pump - Heart
I. General Anatomy of the Heart
A. Location and Size
1. primary organ of the mediastinum
2. 2/3 lie left of the sagittal plane
3. size of a human fist
4. between the sternum and thoracic vertebrae
5. apex - tip of left ventricle
6. left border - left ventricle and atrium
7. superior border - site of great vessels, near atria
8. base - formed by the atria, mainly left atrium
9. right border - formed by right atrium
10. inferior border - right ventricle and part of left
11. sternocostal surface - ventricles and right atrium
12. diaphragmatic surface - mostly left ventricle
B. Pericardium - connective tissue sac around heart
1. fibrous pericardium - outer thick fibrous layer
a. tough bag that surrounds the heart
b. attached to diaphragm
c. continuous with great vessels
2. serous pericardium - inner, thin, double layer
a. parietal layer - fused to fibrous pericardium
i. pericardial fluid - reduces friction
ii. pericardial cavity - space between layers
b. visceral layer (epicardium) - on myocardium
3. pericarditis - inflammation of pericardium
i. cardiac tamponade - compression on the heart
C. The Wall of the Heart - 3 Layers
1. epicardium - visceral layer of pericardium (above)
2. myocardium - heart muscle itself
3. endocardium - thin endothelium lining inside
D. Chambers of the Heart
1. right and left atria - upper chambers
a. auricles – dog-ear like appendages
b. pectinate muscles - bundles of parallel fibers
2. interatrial septum
a. fossa ovalis - closed foramen ovale of fetus
3. right and left ventricles - lower chambers
4. coronary sulcus - exterior groove dividing chambers
5. anterior and posterior interventricular sulci
E. Great Vessels of the Heart
1. Venous return of blood to the Right Atrium via:
a. superior vena cava - from areas above heart
b. inferior vena cava - from areas below heart
c. coronary sinus - from heart muscle itself
2. Right Atrium -> Right Ventricle
3. Right Ventricle to the Lungs via:
a. pulmonary trunk
i. right and left pulmonary arteries
ii. only arteries with unoxygenated blood
4. Lungs -> Left Atrium via:
a. pulmonary veins
i. only veins with oxygenated blood
5. Left Atrium -> Left Ventricle
6. Left Ventricle to entire body via:
a. ascending aorta
i. coronary arteries
ii. arch of the aorta
iii. thoracic aorta
iv. abdominal aorta
7. ductus arteriosus - only in fetus; from pulmonary
trunk to aorta
8. ligamentum arteriosum - remnant in adult
F. Valves of the Heart
1. Atrioventricular Valves (AV)
a. tricuspid valve - between right atrium & ventr.
b. bicuspid valve - between left atrium & ventr.
i. chordae tendinea - attach cusps to muscles
ii. papillary muscles - pull on cusps
2. Semilunar Valves - between ventricles and vessels
a. pulmonary semilunar valve - pulmonary trunk
b. aortic semilunar valve - aorta
II. Blood Supply of the Heart
A. Arterial Supply
1. ascending aorta -> left coronary artery ->
a. anterior interventricular branch
b. circumflex branch
2. ascending aorta -> right coronary artery ->
a. posterior interventricular branch
b. marginal branch
B. Venous return: Coronary Sinus -> Right Atrium
1. tributaries contributing to the coronary sinus:
a. great cardiac vein (drains anterior)
b. middle cardiac vein (drains posterior)