L16-cardiac Development And Congenital Anomalies

Question 1

Origin layer of heart and what does it develop from

Answer 1

Mesoderm

From the two primitive heart tubes formed from mesenchyme in the cardiogenic area of the embryo

Question 2

What does the single primitive heart tube form

Answer 2

Endocardium

Question 3

What forms the myocardium and epicardium

Answer 3

Splanchnic mesoderm

Question 4

What is the endocardial tube formed from

Answer 4

1-truncus arteriosus
2-bulbus cordis
3-primitive ventricle
4-primitive atrium
5-sinus venosus

Question 5

What are the adult derivatives of the truncus arteriosus

Answer 5

Ascending aorta and pulmonary trunk

Question 6

What are the adult derivatives of the bulbus cordis

Answer 6

Smooth the upper part of the right ventricle (conus ateroisus)
smooth upper part of the left ventricle(aortic vestibule)

Question 7

What what are the adult derivatives of the primitive ventricle

Answer 7

Trabeculated part of the right ventricle and trabeculated part of the left ventricle

Question 8

What are the adult derivatives of the primitive atrium

Answer 8

Trabeculated part of the right atrium Trabeculated part of the left atrium

Question 9

What are the adult derivatives of the sinus venosus

Answer 9

Smooth part of the right atrium
Coronary sinus
Oblique vein of the left atrium

Question 10

What happens during the fifth week to the truncus region

Answer 10

Divided by a spiral septum into anterolateral portion the pulmonary artery and a posteromedial portion the aorta

Question 11

How is the left pulmonary artery connected to the dorsal aorta during fetal life

Answer 11

By ductus arteriosus which is forming a prenatal shunt

Question 12

When does septum formation begin

Answer 12

At the end of the fourth week

Question 13

Describe the process of the septum formation

Answer 13

▪️The septum primum a sickle shaped crest descending from the roof of the atrium begins to divide the atrium In to 2 but leaves a lumen: ostium primum
▪️The ostium secundum is formed by cell death that creates an opening in the septum Primum
▪️A septum secundum forms but an interatrial opening:oval foramen persists
▪️Only at birth when pressure in left atrium inc do the two septa press against each other and close communication between the two


Question 14

What does the interventricular septum consist of

Answer 14

A thick muscular part and a thin membranous portion

Question 15

What is transposition of the great vessels

Answer 15

▪️Occurs when the spiral septum fails to follow its normal spiral course and runs straight down
▪️As a consequence the aorta originates from the right ventricle and the pulmonary artery originates from the left ventricle
▪️ sometimes associated with a defect in the membranous part of the interventricular septum and it is usually accompanied by an open ductus arteriosus


Question 16

What is ventricular septal defects

Answer 16

In the membranes or muscular portion of the septum

mostly 80% muscular region

Question 17

What is the tetralogy of Fallot

Answer 17

Abnormality resulting from anterior displacement of the spiral septum and it consists of

1) pulmonary stenosis
2) A large defect of the interventricular septum
3) overriding of the aorta
4) hypertrophy of the right ventricular wall

Question 18

What is patent ductus arteriosus

Answer 18

Under normal circumstances the ductus arteriosis is functionally closed through contraction of its muscular wall shortly after with to form the ligamentum arteriosum
It either maybe an isolated abnormality or made acompany other heart defect especially in premature infants

Question 19

What is coarctation of the heart

Answer 19

Aorta is narrower than usual

The coarctation may be above or below the entrance of the ductus arteriosus preductal or postductal

Question 20

What is dextrocardia

Answer 20

Ventricular inversion
a condition in which the looping of the heart tubes is reversed from its normal pattern producing a heart that has its Apex inferior and to the right rather than left side

Question 21

What causes the changes in the vascular system at birth

Answer 21

By cessation of placental blood flow and the beginning of respiration

Question 22

What are the changes that occur in circulation after birth

Answer 22

Closure of the umbilical arteries:Distal parts of the umbilical arteries form the medial umbilical ligaments, and the proximal portions remain open as the superior vesical arteries.
2- Closure of the umbilical vein and ductus venosus:After obliteration,the umbilical vein forms the ligamentum teres of the liver. The ductus venosus, which courses from the ligamentum teres to the inferior vena cava, is also obliterated and forms the ligamentum venosum.
3- Closure of the ductus arteriosus forms the ligamentum arteriosum.
4- Closure of the oval foramen.