1. Cardiovascular System- The Heart Anatomy Chap. 21

2. The Cardiovascular system is comprised of the heart, blood vessels, & blood
The heart acts as a “pump”, creating pressure which causes blood to move through the blood vessels of the body, allowing O2 & nutrients to be distributed to, & wastes removed from, body tissues

3. Heart Anatomy Overview
Play Heart Anatomy video

4. Anatomical Features of the Heart
The heart lies within the mediastinum of the thoracic cavity
Hollow muscular organ with four internal chambers
(2) atria (lt. atrium & rt. atrium)- receive blood from veins
(2) ventricles (lt. ventricle & rt. ventricle)- pump blood into arteries
Superior aspect of heart is the “base” (3rd intercostal space/sternal angle), where the blood vessels attach; Inferior is the “apex” (5th intercostal space), which rests on the relaxed diaphragm

5. Pericardium The heart lies enclosed within pericardial membranes
Fibrous pericardium (pericardial sac) – outer layer of dense CT that protects & anchors
Serous pericardium – double layered membrane with “pericardial fluid” between
Parietal pericardium – lines the pericardial sac
Visceral pericardium – covers the heart; also known as the “epicardium”

6. Layers of Heart Wall Epicardium (a.k.a. visceral pericardium)
Myocardium
Endocardium

7. Cardiac muscle tissue

8. Because of the characteristics of cardiac muscle tissue & the arrangement of connective tissue (fibrous skeleton) within the heart, the heart basically has two functional units:
the myocardium of the atria (upper chambers) act as one functional unit
the myocardium of the ventricles (lower chambers) act as the other

9. This allows the atria to contract simultaneously while the ventricles are relaxed; then the ventricles contract simultaneously while the atria relax

10. External Features
Auricles
Coronary sulcus – contains the coronary sinus
Anterior interventricular sulcus – contains coronary vessels
Posterior interventricular sulcus – contains coronary vessels

11. Lt Atrium Rt Atrium SVC IVC Deoxygenated blood Interatrial septum
Coronary sinus (opening)
Deoxygenated blood
Interatrial septum
Fossa ovalis
Pulmonary veins
Oxygenated blood
Rt Atrium
Lt Atrium
Pectinate muscles
Tricuspid valve
Bicuspid (mitral) valve
Chordae tendineae
Papillary muscle

12. Atrioventricular (AV) valves
Tricuspid
Bicuspid

13. Lt ventricle Rt ventricle Aorta (ascending) Pulmonary artery
Aortic semilunar valve
Pulmonary semilunar valve
Pulmonary trunk
Pulmonary artery
Trabeculae carneae
Rt ventricle
Lt ventricle
Interventricular septum

14. Semilunar valves

15. Lt ventricle Rt ventricle Ligamentum arteriosum Aortic Arch
Brachiocephalic trunk
Left common carotid artery
Left subclavian artery
Ligamentum arteriosum
Aortic Arch
Aortic semilunar valve
Pulmonary semilunar valve
Pulmonary trunk
Pulmonary artery
Trabeculae carneae
Rt ventricle
Lt ventricle
Interventricular septum

16. Anatomy

17. Coronary Circulation
Myocardium receives oxygenated blood from the left & right Coronary arteries – branches off the ascending aorta
left coronary artery  anterior interventricular branch & circumflex branch
right coronary artery  marginal branch & posterior interventricular branch
Deoxygenated blood is drained through Cardiac veins (Great, posterior, middle & small cardiac veins), which all eventually merge and drain into the coronary sinus

18. Conducting System
Intrinsic regulating system that generates “heartbeat”
comprised of functionally specialized “autorhythmic (conducting) cells” – which can spontaneously generate action potentials
SA node (“pacemaker”)  AV node  AV bundle (of His)  Bundle branches  Purkinje fibers

19. Movement of blood through heart & heart sounds
The activity of the conduction system results in the contraction (systole) & relaxation (diastole) of the heart chambers
atria will contract as ventricles remain relaxed (atrial systole/ventricular diastole). Blood moves from atria to ventricles
as atria relax, ventricles begin to contract (atrial diastole/ventricular systole). The AV valves (tricuspid & bicuspid/mitral) snap shut to prevent backflow of blood into atria. The closing of the valves makes a sound – “Lub”
as blood moves from ventricles to arteries (pulmonary trunk & aorta), pressure will increase in the arteries and decrease in the ventricles. Semilunar valves will then shut  “Dupp” as ventricles relax
all 4 chambers will be in diastole, and then cycle begins again