Heart

Question 1

What is the origin of the heart fields?

Answer 1

Mesodermal origin

Question 2

What structures does the primary heart field develop into?

Answer 2

• Left atrium
• Right atrium
• Left ventricle

Question 3

What structures does the secondary heart field develop into?

Answer 3

• Right ventricle
• Outflow tract

Question 4

What is the role of retinoic acid in heart development?

Answer 4

It is a patterning process for heart fields

Question 5

What can result from disruption of retinoid signaling during heart development?

Answer 5

Heart defects due to mis-specification of tissues

Question 6

What is the significance of lateral folding in heart development?

Answer 6

It brings the forming heart tubes to the midline to fuse into a single tube

Question 7

What does cranio-caudal folding do to the heart tube?

Answer 7

Positions it just ventral to the foregut pocket

Question 8

What is the dorsal mesocardium?

Answer 8

A sling of connective tissue that suspends the heart tube from the body wall

Question 9

What is heart looping?

Answer 9

A controlled process where the ventricle moves ventrally and to the right

Question 10

What condition results from a reversal of heart looping?

Answer 10

Dextrocardia

Question 11

How are the atrio-ventricular canals formed?

Answer 11

By the fusion of dorsal and ventral AV cushions

Question 12

What is the foramen primum?

Answer 12

Space between the free edge of the septum primum and AV cushions

Question 13

What is the role of the septum secundum?

Answer 13

Grows down on the right side of the septum primum and leaves the foramen ovale

Question 14

What happens to the foramen ovale after birth?

Answer 14

Functional closure occurs due to pressure differences between the atria

Question 15

What is a common consequence of incomplete fusion of the septum primum and secundum?

Answer 15

Atrial Septal Defects (ASDs)

Question 16

What is the muscular interventricular septum?

Answer 16

A ridge of muscular tissue that separates the right and left ventricles

Question 17

What is the membranous interventricular septum?

Answer 17

A thinner septum that divides the upper portions of the ventricles

Question 18

What can failure of truncoconal neural crest tissue lead to?

Answer 18

• Persistent truncus arteriosus
• Transposition of the great vessels
• Aortic stenosis
• Pulmonary stenosis

Question 19

What are the components of Tetralogy of Fallot?

Answer 19

• Pulmonary stenosis
• Membranous interventricular septal defect
• Aorta overriding the septal defect
• Right ventricular hypertrophy

Question 20

What is the development process of semilunar valves?

Answer 20

Cavitation of truncoconal ridge tissue to form three triangular valve leaflets

Question 21

What can disruption of AV cushion tissue lead to?

Answer 21

Tricuspid or mitral valve defects

Question 22

What is the fate of the aortic sac during development?

Answer 22

Forms the proximal segment of the aortic arch and brachiocephalic trunk

Question 23

What is the fate of the 1st aortic arch?

Answer 23

Forms the maxillary artery

Question 24

What nerve is associated with the 2nd pharyngeal arch?

Answer 24

Facial nerve (CN VII)

Question 25

What does the 4th left aortic arch become?

Answer 25

Incorporated into the arch of the aorta

Question 26

What happens to the 6th right aortic arch?

Answer 26

The proximal segment is incorporated into the right pulmonary artery and the distal segment regresses

Question 27

What does the 4th RIGHT arch become?

Answer 27

The initial segment of the R subclavian artery

Question 28

What is incorporated into the arch of the aorta from the 4th LEFT arch?

Answer 28

The 4th LEFT arch

Question 29

What happens to the distal segment of the 6th RIGHT arch?

Answer 29

It regresses

Question 30

What does the distal segment of the 6th LEFT arch persist as?

Answer 30

The ductus arteriosus

Question 31

What is the function of the ductus arteriosus?

Answer 31

Augment the right to left shunting of oxygenated blood

Question 32

How does blood primarily shunt from the right atrium to the left atrium?

Answer 32

Via the foramen ovale

Question 33

What induces the closure of the ductus arteriosus postnatally?

Answer 33

Prostaglandins

Question 34

What does the ductus arteriosus eventually become?

Answer 34

The fibrous ligamentum arteriosum

Question 35

How does the regression of the distal segment of the 6th arch affect the recurrent laryngeal nerves?

Answer 35

It affects their course and innervation of the larynx

Question 36

Where is the left recurrent laryngeal nerve found in adults?

Answer 36

Wrapping under the ligamentum arteriosum

Question 37

Where is the right recurrent laryngeal nerve found in adults?

Answer 37

Wrapping under the brachiocephalic trunk

Question 38

What happens to the proximal segment of the right dorsal aorta?

Answer 38

It persists and is incorporated into the R subclavian artery

Question 39

What happens to the distal segment of the left dorsal aorta?

Answer 39

It is retained and incorporated into the descending arch of the aorta

Question 40

What is a double aortic arch?

Answer 40

Abnormal persistence of the distal segment of the RIGHT aortic arch

Question 41

What symptoms are associated with a double aortic arch?

Answer 41

* Dysphagia * Dyspnea

Question 42

What is the result of an aberrant origin of the Right Subclavian Artery?

Answer 42

R subclavian originates from the descending aorta

Question 43

What is the result of a right aortic arch?

Answer 43

Aorta arches to the right rather than the left

Question 44

What occurs in an interrupted aortic arch?

Answer 44

Abnormal regression of the proximal LEFT arch

Question 45

When does the interruption in the aortic arch need to be surgically repaired?

Answer 45

By two weeks after birth

Question 46

What is coarctation of the aorta?

Answer 46

Abnormal constriction of the descending arch of the aorta

Question 47

What are the collateral circulations in coarctation of the aorta?

Answer 47

* Internal thoracic arteries * Intercostal arteries

Question 48

What are the three sets of veins that develop in the embryo?

Answer 48

* Cardinal veins * Vitelline veins * Umbilical veins

Question 49

What does the left-to-right shunting of venous blood cause?

Answer 49

Remodeling of bilaterally symmetrical veins into an asymmetric pattern

Question 50

What happens to the left vitelline vein distal to the liver?

Answer 50

It regresses

Question 51

What does the right vitelline vein enlarge to form?

Answer 51

Veins of the hepatic portal system

Question 52

What develops in the liver from the left umbilical vein?

Answer 52

Ductus venosus

Question 53

What does the left umbilical vein become after birth?

Answer 53

Left medial umbilical ligament

Question 54

What do the anterior cardinal veins drain?

Answer 54

The head and arms

Question 55

What do the posterior cardinal veins drain?

Answer 55

The trunk and legs

Question 56

What does the left brachiocephalic anastomosis result from?

Answer 56

Left-to-right shunting of blood

Question 57

What is a left superior vena cava?

Answer 57

SVC forms on the left connecting to the right atrium via the oblique sinus

Question 58

What occurs in a double superior vena cava?

Answer 58

Two superior vena cavae with no left brachiocephalic vein

Question 59

What causes a double inferior vena cava?

Answer 59

Persistence of the left supracardinal vein

Question 60

What occurs when the inferior vena cava is absent?

Answer 60

Thoracic drainage by azygous and hemiazygous veins