Anatomy cardiac embryology I

Question 1

Cardiac Progenitor cells are derived from where? What do they give rise to?

Answer 1

Derived from intraembryonic mesoderm from the cranial third of the embryo. Give rise to the cardiac cresent (primary heart field)

Question 2

Primary heart field gives rise to

Answer 2

atria, left ventricle, and part of the right ventricle

Question 3

Secondary heart field is derived from where? Gives rise to what?

Answer 3

Derived from splanchnic mesoderm. Forms remainder of the right ventricle and outflow tract (conus cordis and truncus arteriosus)

Question 4

Formation of major layers of the heart

Answer 4

1.) Elongated vascular elements formed from the heart cresent = endocardual tubes (stimulated by vegf) 2.) as lateral folding occurs the tubes fuse together 3.) endocardial tube becomes surrounded by splanchnic mesoderm giving rise to the myocardium 4.) epicardium is formed by population of mesothelial cells

Question 5

Sinus Venosis

Answer 5

consists of confulent left and right sinus horns that receive blod from common cardinal veins

Question 6

What forms the smooth walled portion of the right atrium and the coronary sinus

Answer 6

Sinus venosus and its horns

Question 7

What forms the pectinated portions of the left and right artia

Answer 7

the primitive atrium

Question 8

What Forms the right ventricle

Answer 8

Bulbus Cordis

Question 9

The outflow tract consists of

Answer 9

1.) Conus arteriosus 2.) Truncus arteriosus

Question 10

Fate of Conus arteriosus

Answer 10

becomes incorporated into the left and right ventricles

Question 11

Fate of the Truncus aretriosus

Answer 11

eventually splits to form the ascending aorta and pulmonary artery

Question 12

Describe cardiac looping

Answer 12

On day 23 heart elongates into a C-SHAPE. As it continues to elongates it becomes and S-SHAPE. End result is a 4 chamber heart

Question 13

Division of the atrioventricular canal

Answer 13

end of the 4th week ENDOCARDIAL CUSHIONS develop on the walls of the AV canal separating it into left and right AV canals

Question 14

Septum Primum

Answer 14

thin, crescent shaped membrane that grows from the roof of the primordial atrium towards the endocardial cushion - Leaves an opening called foramen primum.

Question 15

Fate of the Septum Primum

Answer 15

Eventually fuses to the AV septum and closes the foramen primum. BUT right before this happens cells in the dorsal part of the septum go through apoptosis to create a new opening - foramen secundum

Question 16

Foramen Secundum

Answer 16

forms in the septum primum as the foramen primum disappears. Allows shunting of blood from right atrium to left atrium

Question 17

Septum Secundum

Answer 17

gows towards the AV septum covering most of the foramen secundum but stops just before reaching the septum leaving an oeping called the foramen ovale

Question 18

what forms the valve of the foramen ovale

Answer 18

the caudal part of the septum primum

Question 19

Role of valve of the foramen ovale

Answer 19

prevents left to right shunting of blood and closes the foramen ovale at birth

Question 20

Fate of the sinus venousus horns (Left and right)

Answer 20

Right - smooth part of the right atrium (sinus venae cavae). Left- regresses and is tranformed into a small venous sac on the posterior wall of the heart = CORONARY SINUS

Question 21

what forms the smooth walled protion of the left atrium

Answer 21

Primordial pulmonary veins

Question 22

What forms the smooth walled portion of the right atrium

Answer 22

Right sinus venosus

Question 23

Describe the partitioning of the ventricles

Answer 23

At week 4 the bulboventricular groove buldges in until it almost reaches the cushion (leaves the interventricular foramen). At the same time the myocardium begins to thicken and gives rise to trabeculae

Question 24

Division of the truncus arteriossus gives rise to what structures

Answer 24

1.) Pulmonary Trunk 2.) Aorta

Question 25

What causes the division of the truncus arteriosus

Answer 25

the fromation of the aorticopulmonary septum (spiral septum)

Question 26

Development of the aorticopulmonary septum

Answer 26

formed by a series of bulbar and truncal ridges/cushions that spiral down from the level of the aortic valve by making a 180 degree turn towards the interventricular septum. Fuses with the newly formed membranous ventricular septum and completely closes the interventricular foramen.

Question 27

Development of the semilunar valves

Answer 27

During the formation of the aorticopulmonary septum two small cushions of tissue develop within the wall of the outflow tract. Cushions become modified to fom aortic and pulmonary valves

Question 28

Name the non-cyanotic congenital heart defects

Answer 28

1.) Ventricular Septal Defect 2.) Ostium Secundum Defect 3.) Cor triloculare biventriculare 4.) Aortic Stenosis

Question 29

Name the cyanotic congenital heart defects

Answer 29

1.) Tetrology of Fallot 2.) Transposition of the great vessels 3.) Perisitent truncus aretriosus 4.) Tricuspid atresia 5.) Hypoplastic left heart syndrome

Question 30

What is the most common congenital cardiac malformation

Answer 30

Ventricular septal defect

Question 31

Ventricular septal defect

Answer 31

involves the membransous portion of the septum

Question 32

Ostium secundum defect

Answer 32

leaves a large opening between the atria. Due to excessive resportion of septum primum or inadequate development of septum secundum

Question 33

Cor Triloculare Biventriculare

Answer 33

complete absence of the atrial septum

Question 34

Aortic Stenosis

Answer 34

caused by fusion of the cusps of the aortic valve

Question 35

Tetrology of Fallot

Answer 35

due to unequal division of the conus because of displacement of the aorticopulmonary (spiral) septum.

Question 36

What for alteraltions are seen in tetrology of fallot

Answer 36

1) Pulmonary infundibular stenosis 2.) Right ventricular hypertrophy 3.) Overriding aorta that arises durectly above the septal defect 4.) Large IV septal defect (mneumonic: PROV)

Question 37

Transposition of the great vessels

Answer 37

occurs when aorticopulmonary septum fails to follow its course and runs straight down resulting in the aorta originating from the right ventricle and the pulmonary trunk originating from the left ventricle

Question 38

Persistent truncus arteriosus

Answer 38

Failure of fusion of the bulbar and truncal ridges. ALWAYS accompanied by defective IVS. Undivided truncus recieves blood from both sides of the heart

Question 39

Tricuspid atresia

Answer 39

characterized by either the absence of or the fusion of tricuspid valves resulting in obliteration of right atrioventricular orifice

Question 40

Hypoplastic left heart syndrome

Answer 40

left ventricle is underdeveloped. Typicaly there is a large PFO (patent foramen ovale), PDA (Patent ductus arteriosus), hypoplastic ascending aorta/aortic arch and mitral/aortic valves

Question 41

Dextrocardia

Answer 41

the heart is on the right because the heart tube loops left

Question 42

Ectopia cordis

Answer 42

the heart lies on the surface of the chest due to failure of closure of the ventral body wall