DEVELOPMENTAL ANATOMY

Cardiovascular S Cardiovascular Systemystem

Dr. Sukumal Chongthammakun Department of Anatomy, Faculty of Science

Mahidol University

http://intranet.sc.mahidol/AN

Development of Blood Vessels

Development of Blood VesselsLocation: Body, ConnectingStalk, Yol k Sac, Chor i on

Mesenchymal cells (Splanchnic mesoderm)

Development of Cardiogenic Area

Angiogenic clusters• plexus of small blood vessels• ant. portion = cardiogenic area

3Late presomite embryo ( rd week)

Development of cardiogenic area and pericardial cavity

18 days

Development of cardiogenic area and pericardial cavity

intraembryonic coelom = pericardial cavity

18 days

• Head Flexion• Rotation of cardiogenic area

- caudal to prochordal plate

- dorsal to septum transversum(diaphragm) & intraembryonic coelom (pericardial cavity)

Fusion of the Heart Tubes

•Fusion of paired tubes

single tube

Rotation of cardiogenic area & pericardial cavity

180o rotation along a transverse axis

19-20 days

22 days

21 days

Formation of a single heart tube

early presomite embryo (1 7 days)

late presomite embryo ddddd18

Formation of a single heart tube

ddd ddddd2 1 ( 4 )• dddddd dd ddddddddddd ddddd

22 8days (at somites)• dddddd ddddddddddd dddd

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

21 days 22 days

Atrium is the last to fuse. Sinus horns are embedded in the septum transversum.

Formation of a single heart tube

Subdivisions of the Primitive Heart(26 days)

• Lt. & Rt. Aortic arches• Aortic root• Truncus arteriosus• Bul bus cor di s• Ventricle• Atrium• Lt. & Rt. horns of Sinus venosus

Formation of the Cardiac Loop

1 . Bulbus cordis bends in ventral & cau dal & to the right.

2 . Atrium shifts in a dorsal & cranial direction.

3. Bulboventricular sulcus is created.

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 )

22 days 8( somites)

Formation of the Cardiac Loop

24 days 16( somites)

• Primitive atrium moves up into the pericardial cavity

Formation of the Cardiac Loop

28 days

• Atrium grows dorsally to the left• Ventricle & bulbus cordis grows ventrally & to the right

Formation of the Cardiac Loop

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 & pulmo ddddddd.

6 . Bulboventricular sulcus = primary interventricu ddddd ddd.

28days

30 days

At the end of the loop formation

Septum Formation in Common Atrium

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.

30 days(6 mm.)

Septum Formation in Common Atrium33 days(9 mm.)

1. Endocardial cushion extends to close Foramen prim.

2. Foramen (Ostium) secundum is formed. 3. Fusion of endocardial cushions.

4. Septum secundum grows downward/toward endocard ial cushion. 5. Foramen ovale is remained on the inf. border of Sept

dddddddd d.

Septum Formation in Common Atrium

37 days(14 mm.)

Newborn

Septum Formation in Common Atrium

1. Septum secundum is never completed.

2. Left venous & septum spurium fuse wi th septum secundum

3. Oval foramen is formed.

4 . =Septum primum valve of oval foramen.

Differentiation of Atria

1. Right sinus horn incorporates into right atriald ddd = smooth wall of right atrium = sinus venarum

2. Pulmonary vein develops as outgrowth of leftdddddd d ddd dd dddd d ddd dd dddd dddddd=

35 days (7- to 8- mm) Newborn

Development of Venous Valves

35 days (7- to 8- mm) 1. Septum spurium = fusion of Rt. & Lt. venous v

alves. 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

Newborn

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 dddddddd dddd

d & obl i que vei n of the left atrium. 2. Right sinus horn incorporates into the w

all of left atrium. 3. Sinuatrial orifice shifts to the right and is

bordered by right & left venous valves (Sept ) .

• Left venous valves : fuse with atrial septud• Right venous valves : Valve of IVC & Valve

of Coronary sinus

Development of Sinus Venosus

Development of Sinus Venosus

The remains of left sinus horn = oblique vein of left atrium & coronary sinus

Formation of Ventricular Septum

1. Growth of Endocardial cushions

Septum Formation in A-V Canal

1. Endocardial cushions appear. 2. AV canal enlarges to the right. 3 10. Fusion of sup. & inf. Endocardial cushions ( mm.

stage) 4. Rt. & Lt. AV orifices are formed.

Formation of Ventricular Septum2. Growth of ventricular wall to form Muscular ventricular septum

1. Medial wall of ventricles form muscular intervent. septum 2. Outgrowth of inf. EC to close interventricular foramen.

(= membranous interventricular septum)

Formation of Ventricular Septum - 3. Growth of Trunco conal ridges & fusion wit

h endocar di al cushi on

Formation of Ventricular Septum - 3. Growth of Trunco conal ridges & fusion with endoc

ardial cushion

Septum Formation in

Truncus & Conus

Fusion of Rt. & Lt. conus swelling = outflow tracts

of Rt. & Lt. ventricle.

Formation of Cardiac valves

6 wk.

1. Aortic valves & Pulmonary valves (Semilunar valves)

5 wk. 7 wk.

6 wk.

7 wk.

9 wk.

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

Formation of Cardiac valves

4 wk(4 mm.)

Arterial System

dd ddddddd dddddddddd d dddddd ddd&

FateStructureLef t Right

TruncusArteriosus

Root ofPulmonary Trunk(proximal)

Root of Aorta(proximal)

Aortic sac Brachiocephalicartery

Arch of Aorta(proximal)

Fate of Aortic Arches

FateStructure

Right Left

1st Aortic arches Maxillary a. Maxillary a.

2nd Aortic arches Hyoid a. &Stapedial a.

Hyoid a. &Stapedial a.

3rd Aortic arches 1. Common carotida.

2. I nternal carotida. (proximal)

3. External carotida.

1. Common carotida.

2. I nternal carotida. (proximal)

3. External carotida.

FateStructure

Right Left

4th Aortic arches Subclavian a. Arch of Aorta &Subclavian a.

5th Aortic arches - -

6th Aortic arches Right Pulmonarya.

Ductusarteriosus & LeftPulmonary a.

Fate of Aortic Arches

4 mm.

I disappear : rem. = Maxillary a.

II disappear : rem. = Hyoid a. & Stapidial

.

III, IV & VI become larger.

Primitive pulmonary a. is for.

Aortic arches

10 mm.

I & II disappear

VI connect to Pulmonary trunk

Aortic arches

Transformation to Adult Arterial System

Transformation to Adult Arterial

System

Transformation to Adult Arterial System

Other Changes in the Arch System

1

3

4

2

Other Changes in the Arch System

1. Obturation of Carotid duct (Dorsal aorta between III & IV)

2 7. Obturation of Rt. dorsal aorta (at th in tersegmental a.)

3. Lt. subclavian a. shifts to higher point.

4. Recurrent laryngeal n. R dddd dd dddddddddd dd dd =. = hook at Ligamentum arteriosum

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)

Derivatives of Dorsal Aorta

Ventral splanchnic a.d ddd dddd ddd• Vitelline a. dddddd dddd ddd:• Umbilical a.: supply placenta & develodddd visceral organ

Without yolk sac• Celiac a. : supply foregut eg stomach• Sup. mesenteric a.: supply midgut eg.

duodenum& i l eum• Inf. Mesenteric a. : supply hind gut eg.

colon& r ect um

Vitelline and Umbilical Arteries

Venous System

Venous System

1. Vitelline veins

2. Umbilical veins

3. Common cardinal veins• Anterior cardinal veins• Posterior cardinal veins

Vitelline veins

1. LVV are converted into Hepatic sinusoids, Hepatic v. and Portal v.

2. RVV persists as IVC (post-hepatic IVC)

Vitelline veins

4 - 5 wk

4 wk : form plexus to duodenum & septum transversdd

5 wk : form hepatic sinusoid

Vitelline Veins

8 : .wk Rt hepatocardiac channel enlarges

12 wk: RVV is converted into IVC (hepatic portion)

8 - 12 wk

Umbilical veins

1. Differentiation into d dddddd dddddddds

2. LUV & Ductus arteriosus form Liga ment umar t er i osum

3. RUV degenerates

4. LUV (caudal) persists in fetal life

Umbilical veins

5 wk = RUV & LUV connect to Hepatic sinusoid

4 - 5 wk

Umbilical Veins

8 - 12 wk

Ductus venosus is formed. Lt. umbilical vein enlarges.

Anterior Cardinal Veins

7 wk.

1. Anastomosis of AC V shunts blood from L

ACV to RACV& form Le ft Brachiocephalic v.

2. LACV(caudal) degenerates.

3. RACV & RCCV for m SVC

12

3

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)

Fate of Fetal Circulatory Structures

1. Umbilical vein Ligamentum teres hepatis

2. Ductus venosus

3. Umbilical artery

Ligamentum venosum

Medial umbilical ligament

High oxygen ddddddd ddddddddd in :

I Liver II IVC III Rt. atrium IV Lt. atrium

V Desc. Aorta (at the

dddddddd dd dddddd )

Fetal Circulation

Changes at BirthCauses :• cessation of placental blood flow• lung respiration

Changes :1. Cl osure of umbilical a. &fo

rmati onof llll. .2. Cl osure of UV & ductus venosus &formati onof lig. teres &li

g. venosum3. Cl osure of ductus arteri osus by bradykinin &formation of

lig. arteriosum4. Cl osure of oval foramen

1

2

3

4

Lymphatic System

5 wk. origin : mesenchyme or

out growth of endotheliu m of veins

6 primary lymph sacs a re formed :

- 2 jugular lymph sacs - 2 iliac lymph sacs - 1 retroperitoneal

lymph sac - 1 cisterna chyli

• Rt. & LT. Lymphatic ductd• Rt. & Lt. thoracic ducts

Lymphatic System

• Thoracic duct• Rt. lymphatic duct

Formation of Conducting System

1. Pacemaker lies in - initially : left cardiac tube - later : sinus venosus

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 septu) - b. A V canal

Abnormalities of Heart Position

Dextrocardia : cardiac loop to the left. = Heart in the right thorax associated with d

itus inversus (transposition of the viscera)

Ectopia cordis = Heart on the surface of chest caused by fa

ilure to close the midline

Common Congenital Anomalies

Etiologic factors:

1. Disorders of chromosome numbe rs eg. trisomy 2 1 , 1 8 or 1 3

2. Familial disorders

3. Teratogenic viral infections : Rubella

Atrial Septal Defects (ASD)

• Probe patency of Foramen ovale

• Left to right shunt of blood

Atrial Septal Defects (ASD)

Ventricular Septal Defect

• 1500

• Trisomy syndrome

• ddddddd d dd ddddddd dddddddddddddddd dddddd9 0 %

• Shunted from left to right ventricle

Ventricular Septal Defects

Tetralogy of Fallot

• 18500

• Four anomalies : 1. Ventricular septal defect 2. Pulmonary artery stenosis 3. Overiding aorta 4. Right ventricle hypertrophy

Tetralogy of Fallot

Tricuspid Atresia

• 1 in 5 0 0 0• Fusion of tricuspid valves• Patent oval foramen• Ventricular septal defect• Right ventricle atrophy• Left ventricle hypertrophy

Tricuspid Atresia

Patent Ductus Arteriosus

• 13500

• Shunting oxygenated blood to pulmonar y artery

• Prostaglandin synthetase inhibitors eg. dndomet haci n can promote closure of Duct

us ar t er i osus

Patent Ductus Arteriosus

Abnormalities of Semilunar Valves

1. Transposition of great vessels

2. Pulmonary valvularstenosis

Abnormalities of Semilunar Valves

4. Aortic valvularddddddd

3. Aortic valvulardddddddd

Abnormalities of Great Vessels

1. Patent ductus arteriosus

2. Preductal & Postductal coarctation of aorta

Abnormalities of Great Vessels

3. Abnormal origin of Right subclavian a. 4. Double aortic arch

Abnormalities of Great Vessels

Abnormalities of Venous Drainage

Abnormalities of Venous Drainage