1. Heart Anatomy
Dr. Emad Abu Alrub
AAUJ

2. Heart Anatomy Approximately the size of your fist Wt. = 250-300 grams
Location
In the mediastinum between the lungs
Superior surface of diaphragm
⅔’s of it lies to the left of the midsternal line
Anterior to the vertebral column, posterior to the sternum

3. Heart Anatomy
Figure 18.1

4. Coverings of the Heart
Pericardium – a double-walled sac around the heart
Composed of:
A superficial fibrous pericardium
A deep two-layer serous pericardium
The parietal layer lines the internal surface of the fibrous pericardium
The visceral layer or epicardium lines the surface of the heart
They are separated by the fluid-filled pericardial cavity called the pericardial cavity
Protects and anchors the heart
Prevents overfilling of the heart with blood
Allows for the heart to work in a relatively friction-free environment

5. Pericardial Layers of the Heart
Figure 18.2

6. Layers of the Heart Wall
Epicardium – visceral pericardium Myocardium – cardiac muscle layer forming the bulk of the heart Endocardium – endothelial layer of the inner myocardial surface

7. Heart Anatomy External markings Apex - pointed inferior region
Base - upper region
Coronary sulcus
Indentation that separates atria from ventricles
Anterior and posterior interventricular sulcus
Separates right and left ventricles
Internal divisions
Atria (superior) and ventricles (inferior)
Interventricular and interatrial septa

8. Atria of the Heart Atria - receiving chambers of the heart
Receive venous blood returning to heart
Separated by an interatrial septum (wall)
Foramen ovale - opening in interatrial septum in fetus
Fossa ovalis - remnant of foramen ovale
Each atrium has a protruding auricle
Pectinate muscles mark atrial walls
Pump blood into ventricles
Blood enters right atria from superior and inferior venae cavae and coronary sinus
Blood enters left atria from pulmonary veins

9. Gross Anatomy of Heart: Frontal Section
Figure 18.4e

10. Ventricles of the Heart
Ventricles are the discharging chambers of the heart
Papillary muscles and trabeculae carneae muscles mark ventricular walls
Separated by an interventricular septum
Contains components of the conduction system
Right ventricle pumps blood into the pulmonary trunk
Left ventricle pumps blood into the aorta
Thicker myocardium due to greater work load
Pulmonary circulation supplied by right ventricle is a much low pressure system requiring less energy output by ventricle
Systemic circulation supplied by left ventricle is a higher pressure system and thus requires more forceful contractions

11. External Heart: Anterior View
Figure 18.4b

12. Structure of Heart Wall
Left ventricle – three times thicker than right
Exerts more pumping force
Flattens right ventricle into a crescent shape
Figure 18.7

13. Heart Valves
Heart valves ensure unidirectional blood flow through the heart
Composed of an endocardium with a connective tissue core
Two major types
Atrioventricular valves
Semilunar valves
Atrioventricular (AV) valves lie between the atria and the ventricles
R-AV valve = tricuspid valve
L-AV valve = bicuspid or mitral valve
AV valves prevent backflow of blood into the atria when ventricles contract
Chordae tendineae anchor AV valves to papillary muscles of ventricle wall
Prevent prolapse of valve back into atrium

14. Semilunar Heart Valves
Semilunar valves prevent backflow of blood into the ventricles
Have no chordae tendinae attachments
Aortic semilunar valve lies between the left ventricle and the aorta
Pulmonary semilunar valve lies between the right ventricle and pulmonary trunk
Heart sounds (“lub-dup”) due to valves closing
“Lub” - closing of atrioventricular valves
“Dub”- closing of semilunar valves

15. Fibrous Skeleton Surrounds all four valves
Composed of dense connective tissue
Functions
Anchors valve cusps
Prevents overdilation of valve openings
Main point of insertion for cardiac muscle
Blocks direct spread of electrical impulses

16. Heart Valves

17. Cardiac muscle tissue has intrinsic ability to:
Conducting System
Cardiac muscle tissue has intrinsic ability to:
Generate and conduct impulses
Signal these cells to contract rhythmically
Conducting system
A series of specialized cardiac muscle cells
Sinoatrial (SA) node sets the inherent rate of contraction

18. Conducting System

19. Innervation
Heart rate is altered by external controls
Nerves to the heart include:
Visceral sensory fibers
Parasympathetic branches of the vagus nerve
Sympathetic fibers – from cervical and upper thoracic chain ganglia

20. External Heart: Posterior View
Figure 18.4d

21. Major Vessels of the Heart
Vessels returning blood to the heart include:
Superior and inferior venae cavae
Open into the right atrium
Return deoxygenated blood from body cells
Coronary sinus
Opens into the right atrium
Returns deoxygenated blood from heart muscle (coronary veins)
Right and left pulmonary veins
Open into the left atrium
Return oxygenated blood from lungs

22. Major Vessels of the Heart
Vessels conveying blood away from the heart include:
Pulmonary trunk
Carries deoxygenated blood from right ventricle to lungs
Splits into right and left pulmonary arteries
Ascending aorta
Carries oxygenated blood away from left ventricle to body organs
Three major branches
Brachiocephalic
Left common carotid,
Left subclavian artery

23. Blood Flow Through the Heart
Figure 18.6

24. PATHWAY OF BLOOD THROUGH THE HEART AND LUNGS
Figure 18.5

25. The functional blood supply to the heart muscle itself
CORONARY CIRCULATION
The functional blood supply to the heart muscle itself
R and L Coronary arteries are 1st branches off the ascending aorta
Coronary sinus (vein) empties into R. atrium
Collateral routes ensure blood delivery to heart even if major vessels are occluded

26. Coronary Circulation - Arteries
Right Coronary Artery
Supplies blood to
Right atrium and posterior surface of both ventricles
Branches into the
Marginal artery - extends across surface of R. ventricle
Posterior interventricular artery
Found in posterior interventricular sulcus
Left Coronary Artery
Left atrium and left ventricle
Branches into
Circumflex artery
Anterior interventricular artery
Found in anterior interventricular sulcus
Connected with posterior interventricular artery via arterial anastomoses

27. Coronary Circulation: Arterial Supply
Figure 18.7a

28. Coronary Circulation - Veins
Coronary sinus -
Vein that empties into right atrium
Receives deoxygenated blood from:
Great cardiac vein - on anterior surface
Posterior cardiac vein
Drains area served by circumflex
Middle cardiac vein
Drains area served by posterior interventricular artery
Small cardiac vein
Drains blood from posterior surfaces of right atrium and ventricle

29. Coronary Circulation: Venous Supply
Figure 18.7b

30. MICROSCOPIC ANATOMY OF HEART MUSCLE
Cardiac muscle cells
Short, striated, branched, and interconnected
The connective tissue endomysium acts as both tendon and insertion
Intercalated discs anchor cardiac cells together and allow free passage of ions
Heart muscle behaves as a functional syncytium
Many mitochondria (25% of total volume)

31. Microscopic Anatomy of Heart Muscle
Figure 18.11

32. Disorders of the Heart Coronary artery disease
Atherosclerosis – fatty deposits
Arteriosclerosis - hardening of the arteries
Angina pectoris – chest pain
Myocardial infarction – blocked coronary artery
Silent ischemia – no pain or warning
Fibrillation - irregular heart beat; may occur in either atria or ventricles