The Cardiovascular System

Front 1

At what week do we see a primordial heart and the vascular system?

Back 1

Middle of the Third week

Front 2

Where is the cardiovascular system derived from?

Back 2

Splanchic Mesenchyme
Paraxial and lateral mesoderm
Neural Crest Cells

Front 3

Which mesenchyme forms the primordium of the heart ?

Back 3

Splanchic mesenchyme

Front 4

What are angioblastic cords?

Back 4

-paired endothelial strands in the cardiogenic mesoderm that appear around day 18 and are the primordia of the heart

Front 5

What structures form the heart tube?

Back 5

The angioblastic cords when they fuse to form the thin heart tubes during embryonic folding

Front 6

At what day does the heart begin to beat ?

Back 6

22 to 23 days

Front 7

The Three paired veins drain into the tubular heart at what week?

Back 7

4 week embryo

Front 8

What are the three paired veins that drain into the tubular heart?

Back 8

Vitelline Veins
Umbilical Veins
Common Cardinal Veins

Front 9

What does the Vitelline Veins do?

Back 9

They return poorly oxygenated blood from the umbilical vesicle

Front 10

What does the Umbilical Veins do?

Back 10

They carry well oxygenated blood from the chorion or primordial placenta to the sinus venosus

Front 11

What does the Common Cardinal Veins do?

Back 11

They return poorly oxygenated blood from the body of the embryo

Front 12

Which duct connects the midgut with the umbilical vesicle?

Back 12

The Omphaloenteric duct

Front 13

Which duct does the vitelline veins follow?

Back 13

The Omphaloenteric Duct

Front 14

Where does the Vitelline Veins enter?

Back 14

The Venous end of the heart which is knowns as the Sinus Venosus after passing through the septum transversum

Front 15

Which vein forms most of the hepatic portal system and the inferior vena cava?

Back 15

The right Vitelline vein because the left vitelline vein degenerates

Front 16

At what week does the right umbilical vein disappear?

Back 16

Week 7

Front 17

Which vein is left as the only vessel carrying oxygenated blood to the embryo?

Back 17

The Left Umbilical Vein

Front 18

What structure develops within the liver and connects the umbilical vein with the inferior Vena Cava?

Back 18

The Ductus Venosus

Front 19

What does the Ductus Venosus form?

Back 19

forms a bypass through the liver, so most of the blood from the placenta passes directly to the hart without passing through the liver

Front 20

Which veins are the main venous drainage system of the embryo?

Back 20

The Cardinal Veins

Front 21

Which two veins join to enter the sinus venous?

Back 21

The anterior and posterior cardinal veins joining the common cardinal veins

Front 22

The Inferior Vena Cava is formed by which four main segments?

Back 22

Hepatic Segment
Prerenal Segment
Renal Segment
Postrenal Segment

Front 23

Where is the Hepatic Segment derived from?

Back 23

The Hepatic Vein

Front 24

Where is the Prerenal segment derived from?

Back 24

The right subcardinal vein

Front 25

Where is the Renal Segment derived rom?

Back 25

The subcardinal-Supracardinal anastomosis

Front 26

Where is the Postrenal Segment derived from?

Back 26

The Right supracardinal Vein

Front 27

What is Double Superior Vena Cava?

Back 27

When the abnormal left SVC opens into the right atrium through the coronary sinus

Front 28

What is the most common anomaly of the IVC?

Back 28

When its abdominal course is interrupted and results in drainage of the limbs through the azygos system of veins which is an alternate path for blood to the right atrium

Front 29

When does the Left Superior Vena Cava anomaly take place?

Back 29

Occurs when the left anterior cardinal vein persists, forming a SVC on the left side

Front 30

How does the umbilical and vitelline veins develop?

Back 30

...

Front 31

How is the Primordial myocardium formed?

Back 31

The heart tube forms and the Primordial myocardium is formed from the splanchnic mesoderm that surround the pericardial coelom

Front 32

The endothelial lining of the heart becomes which structure?

Back 32

The Endocardium

Front 33

Where is the Epicardium derived from?

Back 33

Mesothelial cells and arises from the sinus venosus and spread over the myocardium

Front 34

What are the five dilatations that become apparent along the length of the heart tube?

Back 34

Truncus Arteriosus (T)
Bulbus Cordis (B)
Primitive Ventricle (PV)
Primitive Atrium (PA)
Sinus Venosus (SV)
These five dilatations develop into the adult structure of the heart

Front 35

What is Dextral Looping?

Back 35

When the primitive heart rotates to the right

Front 36

Why is rotation of the heart so important?

Back 36

It is a key event in the correction of venous flow and proper alignment of the atriventricular canal and the conoventricular canal

Front 37

Where is the bulbar and the truncal ridges derived from?

Back 37

Mesenchymal Cells of the bulbus Cordis

Front 38

How does the partitioning of the Bulbus Cordis and Truncus Arteriosus take place?

Back 38

Neural crest cells migrate through the pharynx and pharyngeal arches to reach the truncal ridges.
-The bulbar and the truncal ridges then undergo a 180 degree spiraling

Front 39

How does the Aorticopulmonary or the AP septum form?

Back 39

Form when the truncal and bulbar ridges fuse

Front 40

What does the AP Septum divide?

Back 40

They divide the Truncus Arteriosus and the Bulbus Cordis into the Aorta and Pulmonary Trunk

Front 41

What is Persistent Truncus Arteriorsus (PTA) caused by?

Back 41

Caused by abnormal neural crest cell migration resulting in partial development of the AP septum
-It results in one large vessel leaving and receiving blood from both the right and left ventricles.
-Usually presents with a membranous ventricular septum defect.
-newborn is severely cyanotic (R to L shunting of blood)

Front 42

What is D-Transportation of the Great Arteries (Complete) caused by?

Back 42

Cause by abnormal neural crest cell migration
-aorta rises from the right ventricle and the pulmonary trunk from the left ventricle so the systemic and pulmonary circulations are separated from each other
-incompatible with life unless a shunt exists like a VSD, patent foramen ovale, or patent ductus arteriosus

Front 43

How is the L-Transportation of the Great Vessels (Corrected)?

Back 43

The aorta and pulmonary trunk are transposed and the ventricles are "inverted" such that the anatomic right ventricle lies on the left side and the anatomic left ventricle lies on the right side
-These two major deviations offset one another such that blood flow pattern is normal

Front 44

What is Tetralogy of Fallot (TF)?
*HIGH YIELD*

Back 44

Pulmonary Stenosis
VSD
Dextraposition of the aorta
Right Ventricular Hypertrophy

Front 45

What is Tetralogy of Fallot caused by?

Back 45

Caused by abnormal neural crest cell migration resulting in skewed development of the AP septum
-results in a pulmonary trunk with a small diameter, whereas the aorta has a large diameter

Front 46

What is Tetralogy of Fallot associated with?

Back 46

Marked cyanosis (R to L shunting of blood)
-Prognosis depends on the severity of pulmonary stenosis

Front 47

At What week does the SA node develop near the entrance of the superior Vena Cava?

Back 47

Week 5

Front 48

What two structures form the cells of the sinus venosus that incorporate into the ventricle?

Back 48

AV node
His Bundle

Front 49

What is the pacemaker of the heart?

Back 49

SA node
AV node
AV bundle

Front 50

Which two nodes stimulate the myocardium?

Back 50

SA node
AV node

Front 51

What structure forms in the roof of the primitive atrium and grows toward the AV cushions in the AV canal?

Back 51

Septum Primum

Front 52

Where does the Foramen Primum form?

Back 52

Between the septum primum and AV cushions
-it closes when the septum primum fuses with the AV cushions

Front 53

What structure forms to the right of the septum primum?

Back 53

Septum Secundum

Front 54

What is the Foramen Ovale?

Back 54

It is the opening between the upper and lower limbs of the septum secundum

Front 55

During embryonic life, blood is shunted from the right atrium to the left atrium via what structure?

Back 55

Foramen Ovale

Front 56

After birth, the functional closure of the foramen oval is facilitated by what?

Back 56

-Decrease int he right atrial pressure from occlusion of placental circulation
-Increase in left atrial pressure due to increased pulmonary venous return

Front 57

What is the most common Atrial Septum Defects?

Back 57

Foramen Secundum Defect
-caused by excessing resorption of septum primum, secundum, or both
-results in an opening between the right and left atria

Front 58

What is Common Atrium (Con Triloculare biventriculare) ?

Back 58

It is a condition in which there is formation of only one atrium

Front 59

What is Premature Closure of Foramen Ovale?

Back 59

It is when there is a closure of foramen ovale during prenatal life
-results in hypertrophy of the right side of the heart and underdevelopment of the left side of the heart

Front 60

What two structures fuse to form the AV septum?

Back 60

The dorsal AV cushion and Ventral AV cushion

Front 61

What does the AV septum partition?

Back 61

Partitions the AV canal into the right AV canal and left AV canal

Front 62

What is Persistent Common AV canal?

Back 62

It is a AV septum defect
-caused by failure of fusion of the AV cushions
-a large hole can be found in the center of the heart
-result is that the tricuspid and bicuspid valves are represented by one valve common to both sides of the heart

Front 63

What is Ebstein's anomaly?

Back 63

It is a AV septum defect
-caused by failure of the posterior and septal leaflets of the tricuspid valve to attach normally to the annulus fibrosus, so they are displaced inferiorly into the right ventricle
-The right ventricle is divided into a large, supper, "atrialized" portion and a small, lower, functional portion

Front 64

What is Tricuspid Atresia? (Hypoplastic Right Heart)

Back 64

-complete agenesis of the tricuspid valve so that there is no communication between the right atrium and right ventricle
-Cyanosis is always associated with patent foramen ovale, IV septum defect, overdeveloped left ventricle and underdeveloped right ventricle

Front 65

Where does the Muscular Interventricular Septum develop?

Back 65

In the midline on the floor of the primitive ventricle and grows toward the fused AV cushions

Front 66

By which structure is the Interventricular Foramen closed by?

Back 66

Membranous Interventricular Septum

Front 67

How is the Membranous Interventricular Septum formed by?

Back 67

proliferation and fusion of three sources:
Right bulbar Ridge
Left Bulbar Ridge
AV cushions

Front 68

What is the most common type of Ventricular Septum Defects?

Back 68

Membranous Ventricular Septum Defect
-caused by faulty fusion of the right bulbar ridge, left bulbar ridge, and AV cushions
-Large VSD presents with R to L shunting of blood, increased pulmonary blood flow and pulmonary hypertension

Front 69

What is Muscular VSD?

Back 69

Caused by single or multiple perforations in the muscular IV septum

Front 70

What is The common ventricle (cor triloculare biatriatum) caused by?

Back 70

failure of the membranous and muscular IV septa to form

Front 71

At which week do the pharyngeal arches form?

Back 71

Week 4 to 5

Front 72

The pharyngeal arches are suppled by which arteries?

Back 72

The pharyngeal or Aortic arch arteries

Front 73

Where does the Aortic Arch arise from?

Back 73

Aortic sac and terminate in the dorsal aortas

Front 74

What two structures form the dorsal aorta?

Back 74

The right and left dorsal aorta

Front 75

What does the Dorsal Aorta sprout into?

Back 75

Posterolateral arteries
Lateral arteries
ventral Arteries (Vitelline and umbilical)

Front 76

Which arteries undergo a complex remodeling process that results in the adult arterial pattern?

Back 76

The Aortic Arch Arteries

Front 77

Where does the right subclavian artery arise from?

Back 77

The distal part of the arch of the aorta and passes posterior to the trachea and esophagus to supply the right upper limb

Front 78

What is Anomalous RIght Subclavian Artery caused by?

Back 78

formation of the right subclavian artery from the right seventh intersegmental artery
-usually no constriction of the trachea and esophagus

Front 79

What is Coarctation of the Aorta?

Back 79

Characterized by the aortic constriction
Two different types:
Postductal Coarctation
Preductal Coarctation

Front 80

Where is Postductal coarctation found?

Back 80

Inferior to the ductus arteriosus
-Clinically associated with increased blood pressure in the upper extremities, lack of pulse in the femoral artery

Front 81

Where is Preductal Coarctation found?

Back 81

The constriction is located superior to the ductus arteriosus

Front 82

What is Double Pharyngeal Arch Artery characterized by?

Back 82

It is characterized by a vascular ring around the trachea and esophagus
-ring results from failure of the distal part of the right aorta to disappear, so right and left arches form

Front 83

What results in a right arch of the aorta?

Back 83

When the entire right dorsal aorta persists and left aorta degenerates

Front 84

Where does the right aortic arch pass through?

Back 84

Right aortic arch may pass anterior or posterior (retroesophageal right arch) to the esophagus and trachea

Front 85

What is the prognosis of a Retroesophageal right arch?

Back 85

May cause difficulties in swallowing or breathing

Front 86

What is Patent Ductus Arteriosus?

Back 86

It is a common anomaly
-The ductus arteriosus, a connection between the left pulmonary arery and aorta, fails to close
-associated with Maternal rubella infection during early pregnancy
-also present in infants born at high altitude, hypoxia and immaturity
-causes L to R shunting of oxygen-rich blood from the aorta back into the pulmonary circulation
-treated with prostaglandin syntheisis inhibitors (indomethacin) which promote closure

Front 87

Which anomaly is associated with maternal rubella infection?

Back 87

Patent Ductus Arteriosus

Front 88

How does fetal circulation of blood take place?

Back 88

-highly oxygenated nutrient rich blood returns under high pressure from the placenta in the umbilical vein
-near the liver half of it passes into the ductus venous, a fetal vessel connecting the umbilical vein to the IVC
-This blood bypasses the liver
-Other half of the blood enters the IVC through the hepatic Veins

Front 89

From which structure does the well oxygenated blood enters the IVC, which opens into the right atrium of the heart?

Back 89

The Ductus Venosus

Front 90

Most blood is directed from the IVC through which structure into the left atrium, where it mixes with the poorly oxygenated blood coming from the lungs through the pulmonary veins?

Back 90

OVAL FORAMEN

Front 91

How does the blood leave from the heart through the ascending aorta?

Back 91

Blood goes from the left atrium and passes to the left ventricle and leaves the heart through the ascending aorta

Front 92

What does the ascending aorta supply?

Back 92

Oxygenated blood to the arteries of the heart, head and the upper limbs

Front 93

Which vein does the liver receive its well oxygenated blood?

Back 93

The Umbilical vein

Front 94

What happens to the blood from the IVC in the right atrium that does not enter the Foramen Ovale?

Back 94

It mixes with poorly oxygenated blood from the SVC and coronary sinus and passes into the right ventricle
-This oxygenated blood leaves through the pulmonary trunk

Front 95

What percent of the blood goes to the lungs from the descending aorta?

Back 95

10 %, most of it passes through the DA into the descending aorta to the fetal body and returns to the placenta through the umbilical arteries

Front 96

65% of the blood from the descending aorta passes into which structure?

Back 96

Passes into the umbilical arteries and is returned to the placenta for re-oxygenation

Front 97

After birth, which structures close?

Back 97

Umbilical vessels
DA
DV
Oval Foramen

Front 98

How does the closure of the Oval Foramen take place?

Back 98

High pressure in the left atria functionally closes the oval foramen by pressing the valve of the oval foramen against the septum secundum

Front 99

Which structure becomes the Ligamentum arteriosus?

Back 99

When the DA constricts at birth

Front 100

The closure of the DA is mediated by what protein?

Back 100

Bradykinin which is released by the lungs during their initial inflation