1. Cardiovascular System
DEVELOPMENTAL ANATOMY
Cardiovascular System
Dr. Sukumal Chongthammakun
Department of Anatomy, Faculty of Science
Mahidol University

2. Development of Blood Vessels

3. Development of Blood Vessels
Location: Body, Connecting Stalk, Yolk Sac, Chorion

4. (Splanchnic mesoderm)
Development of Cardiogenic Area
Late presomite embryo (3rd week)
Mesenchymal cells
(Splanchnic mesoderm)
Angiogenic clusters
plexus of small blood vessels
ant. portion = cardiogenic area

5. Development of cardiogenic area and pericardial cavity
18 days

6. intraembryonic coelom = pericardial cavity
Development of cardiogenic area and pericardial cavity
18 days
intraembryonic coelom = pericardial cavity

7. Fusion of the Heart Tubes
Head Flexion
Rotation of cardiogenic area
- caudal to prochordal plate
- dorsal to septum transversum(diaphragm) & intraembryonic coelom (pericardial cavity)
Fusion of paired tubes
single tube

8. Rotation of cardiogenic area & pericardial cavity
180o rotation along a transverse axis
21 days
22 days
days

9. Formation of a single heart tube
late presomite embryo
(18 days)
early presomite embryo
(17 days)

10. Formation of a single heart tube
21 days (at 4 somites)
Fusion of endocardial tubes
22 days (at 8 somites)
Single endocardial tube

11. Formation of Myoepicardial Mantle
Splanchnic mesoderm surrounds the heart
Cardiac jelly (extracellular matrix)
- rich in collagen & glycoproteins
- play role in cardiac morphogenesis
Myoepicardial Mantle
Myocardium
Epicardium

12. Formation of a single heart tube
21 days
22 days
Atrium is the last to fuse.
Sinus horns are embedded in the septum transversum.

13. Subdivisions of the Primitive Heart (26 days)
Lt. & Rt. Aortic arches
Aortic root
Truncus arteriosus
Bulbus cordis
Ventricle
Atrium
Lt. & Rt. horns of Sinus venosus

14. Formation of the Cardiac Loop
1. Bulbus cordis bends in ventral & caudal & to the right.
2. Atrium shifts in a dorsal & cranial direction.
3. Bulboventricular sulcus is created.

15. Formation of the Cardiac Loop
U-shaped & convexed forward and to the right
Ventricular growth
S-shaped & bulboventricular sulcus in concaved loop
23 days
(11 somites)
22 days
(8 somites)

16. Formation of the Cardiac Loop
Primitive atrium moves up into the pericardial cavity
24 days
(16 somites)

17. Formation of the Cardiac Loop
Atrium grows dorsally to the left
Ventricle & bulbus cordis grows ventrally & to the right
28 days

18. Formation of the Cardiac Loop
28days
1. Common atrium incorporated into pericardial cavity.
2. Atrioventricular canal is narrowed.
3. Bulbus cordis is narrowed, except trabeculated part of right ventricle.
4. Conus cordis will form outflow tracts of ventricles.
5. Truncus cordis will form roots of aorta & pulmonary artery.
6. Bulboventricular sulcus = primary interventricular foramen.

19. At the end of the loop formation
30 days

20. Septum Formation in Common Atrium
30 days
(6 mm.)
1. Endocardial cushions are formed in the AV canal.
2. Septum primum grows from the roof of common atrium.
3. Foramen (Ostium) primum is formed.
4. Perforation appears in septum primum.

21. Septum Formation in Common Atrium
33 days(9 mm.)
1. Endocardial cushion extends to close Foramen primum.
2. Foramen (Ostium) secundum is formed.
3. Fusion of endocardial cushions.
4. Septum secundum grows downward/toward endocardial cushion.
5. Foramen ovale is remained on the inf. border of Septum secundum.

22. Septum Formation in Common Atrium
Newborn
37 days
(14 mm.)

23. Septum Formation in Common Atrium
1. Septum secundum is never completed.
2. Left venous & septum spurium fuse with septum secundum
3. Oval foramen is formed.
4. Septum primum = valve of oval foramen.

24. Differentiation of Atria
35 days (7- to 8- mm)
Newborn
1. Right sinus horn incorporates into right atrial wall
= smooth wall of right atrium = sinus venarum
2. Pulmonary vein develops as outgrowth of left atrial wall
= smooth wall of left atrium

25. Development of Venous Valves
Newborn
35 days (7- to 8- mm)
1. Septum spurium = fusion of Rt. & Lt. venous valves.
2. Sup. portion of Rt. venous valve disappears.
3. Inf. portion of Rt. venous valve = valve of IVC & valve of coronary sinus
4. Crista terminalis = dividing line

26. Changes in Sinus Venosus
35 days
1. The veins to left sinus horn degenerates.
2. Right sinus horn moves to the right side.
8 week
1. Left sinus horn becomes coronary sinus & oblique vein of the left atrium.
2. Right sinus horn incorporates into the wall of left atrium.
3. Sinuatrial orifice shifts to the right and is bordered by right & left venous valves (Septum spurium).
Left venous valves : fuse with atrial septum
Right venous valves : Valve of IVC & Valve of Coronary sinus

27. Development of Sinus Venosus

28. Development of Sinus Venosus
The remains of left sinus horn
= oblique vein of left atrium & coronary sinus

29. Formation of Ventricular Septum
1. Growth of Endocardial cushions

30. Septum Formation in A-V Canal
1. Endocardial cushions appear.
2. AV canal enlarges to the right.
3. Fusion of sup. & inf. Endocardial cushions (10 mm. stage)
4. Rt. & Lt. AV orifices are formed.

31. Formation of Ventricular Septum
2. Growth of ventricular wall to form Muscular ventricular septum

32. 1. Medial wall of ventricles form muscular intervent. septum
2. Outgrowth of inf. EC to close interventricular foramen.
(= membranous interventricular septum)

33. Formation of Ventricular Septum
3. Growth of Trunco-conal ridges & fusion with endocardial cushion

34. Formation of Ventricular Septum
3. Growth of Trunco-conal ridges & fusion with endocardial cushion

35. Septum Formation in Truncus & Conus
Fusion of Rt. & Lt. conus swelling = outflow tracts of Rt. & Lt. ventricle.

36. Formation of Cardiac valves
1. Aortic valves & Pulmonary valves (Semilunar valves)
5 wk.
6 wk.
7 wk.
6 wk.
7 wk.
9 wk.

37. Formation of Cardiac valves
2. Mitral valves & Tricuspid valves (Atrioventricular Valves)
1. Proliferation of mesenchyme in A-V orifice.
2. The cords becomes hollowed out by bloodstream.
3. The muscular tissue degenerates, replaced by dense CNT.
4. A-V valves = CNT covered by endocardium connected to papillary muscles by chordae tendineae.
5. Right = tricuspid valves Left = bicuspid (Mitral) valves

38. Arterial System
4 wk
(4 mm.)

39. Fate of Truncus Arteriosus & Aortic Sac

40. Fate of Aortic Arches

41. Fate of Aortic Arches

42. Aortic arches 4 mm. I disappear : rem. = Maxillary a. II disappear :
rem. = Hyoid a. & Stapidial a.
III, IV & VI become larger.
Primitive pulmonary a. is formed.

43. Aortic arches
10 mm.
I & II disappear
VI connect to Pulmonary trunk

44. Transformation to Adult Arterial System

45. Transformation to Adult Arterial System

46. Transformation to Adult Arterial System

47. Other Changes in the Arch System1 4 2 3

48. Other Changes in the Arch System
1. Obturation of Carotid duct (Dorsal aorta between III & IV)
2. Obturation of Rt. dorsal aorta (at 7th intersegmental a.)
3. Lt. subclavian a. shifts to higher point.
4. Recurrent laryngeal n Rt = hook at Subclavian a Lt = hook at Ligamentum arteriosum

49. Derivatives of Dorsal Aorta
Intersegmental a.
supply ribs, intercostal m. & spinal cord
C & L segments - supply limbs
Lateral splanchnic a.
supply kidneys & gonads (intermediate mesoderm)

50. Derivatives of Dorsal Aorta
Ventral splanchnic a.
With yolk sac
Vitelline a. : supply yolk sac
Umbilical a.: supply placenta & developing visceral organ
Without yolk sac
Celiac a. : supply foregut eg stomach
Sup. mesenteric a.: supply midgut eg duodenum & ileum
Inf. Mesenteric a.: supply hind gut eg colon & rectum

51. Vitelline and Umbilical Arteries

52. Venous System

53. Venous System 1. Vitelline veins 2. Umbilical veins
3. Common cardinal veins
Anterior cardinal veins
Posterior cardinal veins

54. Vitelline veins
1. LVV are converted into Hepatic sinusoids, Hepatic v. and Portal v.
2. RVV persists as IVC (post-hepatic IVC)

55. Vitelline veins
4 - 5 wk
4 wk : form plexus to duodenum & septum transversum
5 wk : form hepatic sinusoid

56. Vitelline Veins 8 wk : Rt. hepatocardiac channel enlarges
12 wk: RVV is converted into IVC (hepatic portion)

57. Umbilical veins 1. Differentiation into Hepatic sinusoids
2. LUV & Ductus arteriosus form Ligamentum arteriosum
3. RUV degenerates
4. LUV (caudal) persists in fetal life

58. Umbilical veins
4 - 5 wk
5 wk = RUV & LUV connect to Hepatic sinusoid

59. Umbilical Veins Ductus venosus is formed. Lt. umbilical vein enlarges.wk
Ductus venosus is formed.
Lt. umbilical vein enlarges.

60. Anterior Cardinal Veins1 2 3
1. Anastomosis of ACV shunts blood from LACV to RACV& form Left Brachiocephalic v.
2. LACV(caudal) degenerates.
3. RACV & RCCV form SVC
7 wk.

61. Posterior Cardinal Veins
1. Degenerate with the development of metanephric kidney
2. Persists as common iliac v. & Root of Azygos v.
3. Two temporary venous system develop
a.) Subcardinal v. develops into
LRV, Gonadal v., Suprarenal v., IVC (hepatic segment)
b) Supracardinal vein develops into
Azygos v.
Hemiazygos v.
IVC (lower)

63. Fate of Fetal Circulatory Structures
1. Umbilical vein
Ligamentum teres hepatis
2. Ductus venosus
Ligamentum venosum
3. Umbilical artery
Medial umbilical ligament

64. Fetal Circulation High oxygen content decreased in : I Liver II IVC
III Rt. atrium
IV Lt. atrium
V Desc. Aorta (at the entrance of ductus arteriosus)

65. Changes at Birth 3 Causes : 4 Changes : 2 1
cessation of placental blood flow
lung respiration 4
Changes :
1. Closure of umbilical a. & formation of med. umbilical lig.
2. Closure of UV & ductus venosus & formation of lig. teres & lig. venosum
3. Closure of ductus arteriosus by bradykinin & formation of lig. arteriosum
4. Closure of oval foramen 2 1

66. Lymphatic System
5 wk.
origin : mesenchyme or out growth of endothelium of veins
6 primary lymph sacs are formed :
- 2 jugular lymph sacs
- 2 iliac lymph sacs
- 1 retroperitoneal lymph sac
- 1 cisterna chyli

67. Lymphatic System Rt. & LT. Lymphatic ducts Rt. & Lt. thoracic ducts
Rt. lymphatic duct

68. Formation of Conducting System
1. Pacemaker lies in
- initially : left cardiac tube
- later : sinus venosus

69. Formation of Conducting System
2. Incorporation of sinus into Rt. atrium.
3. Sinuatrial node is formed.
4. A-V node & Bundle of His are derived from cells of
a. left wall of sinus venosus (base of interatrial septum)
b. A-V canal

70. Abnormalities of Heart Position
Dextrocardia : cardiac loop to the left.
= Heart in the right thorax associated with situs inversus (transposition of the viscera)
Ectopia cordis
= Heart on the surface of chest caused by failure to close the midline

71. Common Congenital Anomalies
Etiologic factors:
1. Disorders of chromosome numbers eg. trisomy 21, 18 or 13
2. Familial disorders
3. Teratogenic viral infections : Rubella

72. Atrial Septal Defects (ASD)
Probe patency of Foramen ovale
Left to right shunt of blood

73. Atrial Septal Defects (ASD)

74. Ventricular Septal Defect
1 in 500
Trisomy syndrome
90% involve Membranous interventricular septum
Shunted from left to right ventricle

75. Ventricular Septal Defects

76. Tetralogy of Fallot 1 in 8500 Four anomalies :
1. Ventricular septal defect
2. Pulmonary artery stenosis
3. Overiding aorta
4. Right ventricle hypertrophy

77. Tetralogy of Fallot

78. Tricuspid Atresia 1 in 5000 Fusion of tricuspid valves
Patent oval foramen
Ventricular septal defect
Right ventricle atrophy
Left ventricle hypertrophy

79. Tricuspid Atresia

80. Patent Ductus Arteriosus
1 in 3500
Shunting oxygenated blood to pulmonary artery
Prostaglandin synthetase inhibitors eg. indomethacin can promote closure of Ductus arteriosus

81. Patent Ductus Arteriosus

82. Abnormalities of Semilunar Valves
1. Transposition of
great vessels
2. Pulmonary valvular
stenosis

83. Abnormalities of Semilunar Valves
3. Aortic valvular
stenosis
4. Aortic valvular
atresia

84. Abnormalities of Great Vessels
1. Patent ductus arteriosus
2. Preductal & Postductal coarctation of aorta

85. Abnormalities of Great Vessels
3. Abnormal origin of Right subclavian a.
4. Double aortic arch

86. Abnormalities of Great Vessels

87. Abnormalities of Venous Drainage

88. Abnormalities of Venous Drainage