1. The document describes the anatomy and structure of the cardiovascular system, including the heart, blood vessels (arteries, veins, capillaries), conduction system, and circulatory routes. 2. It explains the layers of the heart (epicardium, myocardium, endocardium), chambers (atria, ventricles), valves (atrioventricular, semilunar), and associated vessels (aorta, vena cava, pulmonary arteries/veins). 3. The fetal circulation is described, which differs from adult circulation in that blood bypasses the lungs via the foramen ovale and ductus arteriosus. These changes allow blood to mix and circulate after

1. Professor Md.Toufiqur
Rahman
MBBS, FCPS, MD, FACC, FESC, FRCP, FSCAI,
FCCP,FAPSC, FAPSIC, FAHA,FACP,FASE
Professor and Head of Cardiology
Colonel Malek Medical College , Manikganj
.drtoufiq19711@yahoo.com
Anatomy of
Cardiovascular System

2. The Cardiovascular System
• A closed system of the heart and blood
vessels
– The heart pumps blood
– Blood vessels allow blood to circulate to all
parts of the body
• The function of the cardiovascular system
is to deliver oxygen and nutrients and to
remove carbon dioxide and other waste
products

3. Cardiovascular System-parts
• Also circulatory system
• Consists of: the heart, arteries, veins,
capillaries

4. Heart
• Four chamber muscular organ
• Comparable to the size of a closed fist
• Located in the mediastinum
– Behind sternum
– Between 2nd - 6th ribs
– Between T5-T8
• Apex – base of heart
– Located at the 5th
– intercostal space

5. Heart

6. External Heart Anatomy

7. Coverings of the Heart
• Pericardium – loose fitting sac
surrounding the heart
– Fibrous pericardium – tough, loose-fitting,
inelastic
– Serous pericardium
• Parietal layer: lines the inside of the fibrous
pericardium
• Visceral layer: adheres to outside of the heart
– Pericardial space: between parietal and
visceral layer
• Filled with 10-15mL of pericardial fluid
• Decreases friction

8. Walls of the Heart
• Epicardium – outer layer
– Epicardium = serous pericardium
• Myocardium – thick, contractile layer composed
of cardiac muscle cells
– Intercalated disks contain many gap junctions
– Allow cardiac muscle cells to function as a single unit
 syncytium
• Endocaridium – interior of cardiac wall
– Endothelial tissue
– Covers projections of myocardial tissue called
trabeculae

9. Walls of the Heart

10. Chambers of the Heart
• Atria – two superior chambers
– “Receiving chambers”
– Blood from veins enters atria
• Ventricles – two inferior
chambers
– “pumping chambers”
– Thick muscular walls to
– increase force of pumping
action
• Left > right
– Separated by interventricul
– ar septum

12. Valves of the Heart
• Permit blood flow in one direction during
circulation
• Atrioventricular valves (AV valves)
– Also cuspid valves
– Between atria and ventricles
• Semilunar (SL valves)
– Between R ventricle and pulmonary arteries
and L ventricle and aorta

14. Atrioventricular Valves
• Tricuspid valve
– Btwn R atrium and ventricle
– 3 flaps of endocardium
– Connected to ventricular papillary muscle
via chordae tendinae
• Bicuspid valve
– Btwn L atrium and ventricle
– Also called mitral valve
– Two flaps of endocardium

15. Semilunar Valves
• Pulmonary semilunar valve
– Btwn R ventricle and pulmonary trunk
• Aorta semilunar valve
– Btwn L ventricle and aorta

16. Operation of Heart Valves

17. The Heart:
Associated Great Vessels
• Aorta - leaves left ventricle
• Pulmonary arteries - leave right ventricle
• Vena cava - enters right atrium
• Pulmonary veins (four) - enter left atrium

18. Coronary Circulation
• Blood in the heart chambers does not
nourish the myocardium
• The heart has its own nourishing
circulatory system
– Coronary arteries
– Cardiac veins
– Blood empties into the right atrium via the
coronary sinus

19. Blood Supply to the Heart
• Right and left coronary arteries
– First branches off aorta
– Right coronary artery  right marginal
artery & posterior interventricular artery
– Left coronary artery  circumflex artery
& anterior interventricular artery
– Most of the blood goes to the L ventricle
– In 50% of the population, the R coronary
artery is dominant

20. Anterior view
Posterior view

22. Blood Supply to the Heart
• Anastomosis: Connections between blood
vessels that allow for collateral circulation
• Few exist between large branches of coronary
arteries
• In presence of an obstruction in a large
artery ischemia will result to a large area of
tissue
– Myocardial infarction (MI) (aka heart attack)
• Anastomoses do exists between smaller
branches of the R and L coronary arteries

23. Blood Supply to the Heart
• After traveling through the capillaries
of the heart, blood empties into the R
atrium via the coronary sinus

25. Conduction System of the Heart
• Four structures composed of modified
cardiac muscle
• Sinoatrial Node (SA Node)
– Pacemaker of the heart
– 100s of cells in the R atrium near the
opening of the superior vena cava
• Atrioventricular Node (AV Node)
– Small mass of cardiac muscle tissue
– Left lower border of R atrium

28. Conduction System of the Heart
• Atrioventricular Bundle
– Also Bundle of His
– Bundle of specialized cardiac muscle fibers
originating in the AV node
– Branches into R and L branches eventually
becoming Purkinje fibers
– Extend into the walls of the ventricles and
papillary muscles

29. Types of Blood Vessels
• Artery – carries oxygenated blood away
from the heart
– “distributors”
– Arteriole: small artery
– Precapillary sphincters: regulate the blood
flow into capillaries

30. Types of Blood Vessels
• Vein – carries unoxygenated blood
towards the heart
– Great ability to stretch (capacitance)
– Function as reservoirs: blood pools in the
valves then is pushed forward from the
pumping pressure
– Venules: small vein

31. Types of Blood Vessels

32. Types of Blood Vessels
• Capillaries – arterial system switches to
venous system
– “primary exchange vessels”
– Transport materials to and from the cells
– Speed of blood flow decreases to increase
contact time
– Microcirculation: blood flow between
arterioles, capillaries and venules

33. Types of Blood Vessels

34. Structure of Blood Vessels
• Tunica adventitia - outermost layer
– Fibrous connective tissue
– Holds vessels open; prevents tearing of
vessels walls during body movements
– Larger in veins than arteries
• Tunica media – middle layer
– Smooth muscle and elastic CT
– Helps vessels constrict and dilate
– Larger in arteries

35. Structure of Blood Vessels
• Tunica intima – innermost layer
– Composed of endothelium
– Semilunar valves present in veins
– One cell thick in capillaries

36. Circulatory Routes
• Systemic Circulation – blood flow from
the L ventricle to the body & back to
the R atrium
• Pulmonary Circulation – blood flow from
the R ventricle to the lungs and back to
the L atrium

40. Circulatory Routes

41. Aorta

42. Systemic Arteries
• Arch of aorta
• Subclavian (L and R)
• Brachiocephalic
• common carotid (L
and R)
• Axillary (L and R)
• Brachial (L and R)
• Radial
• Ulnar
• Abdominal aorta
• Common iliac
• External iliac
• Femoral
• Popliteal
• Posterior tibial
• Anterior tibial
• Dorsal pedis

44. The Vascular System

45. Systemic Veins
• Superior vena cava
• Inferior vena cava
• External jugular
• Internal jugular
• Brachiocephalic (L
and R)
• Subclavian (L and R)
• Cephalic
• axillary
• Basilic
• Median basilic
• Median cubital
• Common iliac
• External iliac
• Femoral
• Popliteal
• Great saphenous
• Small saphenous

47. Fetal Circulation
• Two umbilical arteries carry blood to the
placenta
• The placenta allows for exchange of oxygen
and nutrients from the mother. Maternal and
fetal blood do NOT mix.
• Umbilical vein returns oxygenated blood and
enters fetus via the umbilicus
• Foramen ovale – hole btwn the R and L atria
– Allows for blood to bypass the R ventricle and
pulmonary circulation

48. Fetal Circulation
• Ductus arteriosus – small vessel
connecting the pulmonary artery and
the aorta
– Allows for another bypass route from the
lungs
**Most of fetal blood is a mixture of
oxygenated and deoxygenated blood**

49. Fetal Circulation

50. Changes After Birth
• Umbilical vein become round ligament
• Umbilical arteries become umbilical
ligaments
• Foramen ovale closes after first few
breaths
– Full closure may take up to 9 months
• Ductus arteriosus contracts as soon as
respirations begin
– Become fibrous cord

51. Changes After Birth

52. Developmental Aspects of the
Cardiovascular System
• A simple “tube heart” develops in the
embryo and pumps by the fourth week
• The heart becomes a four-chambered
organ by the end of seven weeks
• Few structural changes occur after the
seventh week