CVS embryology

Question 1

where do blood vessels first appear

Answer 1

the yolk sac, allantois, connecting stalk and chorion

–this is called the cardiogenic field

Question 2

where do the heart tubes from from

Answer 2

blood vessels in lateral plate splanchnic mesoderm

Question 3

where does the heart lie in relation to

Answer 3

dorsal to pericardial cavity

Question 4

where does parietal and fibrous pericardium form from

Answer 4

somatic mesoderm

Question 5

where does visceral pericardium form from

Answer 5

splanchnic mesoderm

Question 6

where does pericardial cavity form from

Answer 6

intra-embryonic coelom

Question 7

what does the caudal and cephalic end become

Answer 7

caudal- veins

cephalic- arteries

Question 8

whats the name of the fold of heart tube

Answer 8

bulboventricular loop

Question 9

what happens in formation of bulboventricular loop

Answer 9

Bulbus cordis and ventricle enlarge and loop to the right →

Ventricle pushed left and inferiorly

Atria pushed superiorly and posteriorly

Question 10

birth defects: dextrocardia

Answer 10

Heart tube loops to left side (instead of right side)

so ventricles come to lie facing the right

Question 11

Formation of left and right atrioventricular canals

Answer 11

Endocardial cushion growth

separates right atrium + ventricle

from left atrium + ventricle to form L & R AV canals

Question 12

Partitioning of Primitive Atrium into left & right atria

Answer 12

septum primum and ostium primum grow

ostium secundum grows after apoptosis of septum primum

eventually making foramen ovale

Question 13

role of foramen ovale

Answer 13

allows blood to pass through atria as doesn’t need to go to right ventricle for lungs

Question 14

what happens to the foramen ovale after birth

Answer 14

septum primum fuses with the septum secundum

making fossa ovalis

Question 15

non closure of foramen ovale is called

Answer 15

patent foramen ovale

a common congenital Atrial Septal Defect

Question 16

Partitioning of Primitive Ventricle

Answer 16

Muscular ventricular septum forms. Opening is called interventricular foramen.

Aorticopulmonary septum divides bulbiscordis and truncus arteriosus into aorta and pulmonary trunk.

Bottom of spiral aorticopulmonary septum fuses with muscular ventricular septum and endocardial cushions to form membranous interventricular septum, closing interventricular foramen

Question 17

birth defects: Ventricular Septal Defect (VSD)

Answer 17

hole in middle septum

can close spontaneously

Question 18

Partitioning of Bulbus Cordis (BC) and Truncus Arteriosus (TA)

Answer 18

aorticopulmonary septum divides BC and TA into aorta and pulmonary trunk

Question 19

Transposition of Great vessels

Answer 19

Common cause of cyanotic disease in newborn infants

Permit exchange of systemic and pulmonary circulation

Question 20

causes of transposition of great vessels

Answer 20

1) Failure of aorticopulmonary septum to take a spiral course
2) Defective migration of neural crest cells to heart

Question 21

what develops from the ventricular wall

Answer 21

• The cusps
• chordae tendineae
• papillary muscles

of the atrioventricular valves

Question 22

how are the semilunar valves formed

Answer 22

from subendocardial valve tissue.

Question 23

how are atrium and sinus venosus made

Answer 23

Early pacemakers- SA node

-cardiomyocytes

Question 24

SA node development time and location

Answer 24

5th week

high in the right atrium near the entrance of the SVC

Question 25

where does the AV node and bundle of His develope

Answer 25

from cells of AV canal and sinus venosus

Question 26

what goes wrong to cause cot death

Answer 26

abnormalities in conducting tissue

Question 27

Heart tube derivatives: aortic sac

Answer 27

aortic arches

Question 28

Heart tube derivatives: bulbus cordis

Answer 28

right ventricle parts of outflow tracts

Question 29

Heart tube derivatives: primative ventricle

Answer 29

left ventricle

Question 30

Heart tube derivatives: primitive atrium

Answer 30

parts of right and left atria

Question 31

Heart tube derivatives: sinus venosus

Answer 31

superior vena cava right atrium

Question 32

what are the first arteries to appear in an embryo

Answer 32

left an right primitive aorta with a ventral and dorsal part

Question 33

aortic sac structure and derivatives

Answer 33

made up of 2 ventral aortae then becomes truncus arteriosus eventually making aortic branch

Question 34

aortic arches unite with

Answer 34

dorsal aortae

Question 35

aortic arches give rise to

Answer 35

great arteries of the head and neck

Question 36

how do blood vessels develop

Answer 36

•Vasculogenesis defined as the **new formation** of a primitive vascular network •Angiogenesis defined as the growth of new vessels **from pre-existing** blood vessels

Question 37

Adult derivatives of Aortic Arches: 1st and 2nd

Answer 37

disappear

Question 38

Adult derivatives of Aortic Arches: 3rd

Answer 38

forms the common carotid artery

Question 39

Adult derivatives of Aortic Arches: 4th

Answer 39

forms right subclavian

Question 40

Adult derivatives of Aortic Arches: 5th

Answer 40

dissapears

Question 41

Adult derivatives of Aortic Arches: 6th right arch

Answer 41

right pulmonary artery

Question 42

Adult derivatives of Aortic Arches: 6th left arch

Answer 42

left pulmonary artery ductus arteriosus

Question 43

birth defects: aortic arches

Answer 43

often persistence of aortic arches that either normally should regress or regression of arches that normally shouldn’t. eg. **right subclavian** artery sometimes has abnormal origin on the **left** →may constrict trachea and oesophagus

Question 44

birth defects: double aortic arch

Answer 44

non-regression of the **right aortic arch** forming a **vascular ring** around the trachea and oesophagus,

Question 45

birth defects: patent ductus arteriosus

Answer 45

Failure of muscular wall to contract- respiratory distress syndrome associated with maternal rubella infection

Question 46

birth defects: coarction of aorta

Answer 46

aorta is narrow, usually where ductus arteriosus (ligamentum arteriosum) inserts.

Question 47

vitelline vessels supply

Answer 47

yolk sac- adult gut vessels

Question 48

umbilical vessels supply

Answer 48

placenta- internal illiac

Question 49

cardinal vessels supply

Answer 49

rest of body- SVC and IVC

Question 50

lymph sac development

Answer 50

Six primary lymph sacs develops at the end of embryonic period Lymphatic vessels will later join the lymph sacs

Question 51

what does thoracic duct develop from

Answer 51

vessels anterior to aorta becoming left and right embryonic thoracic ducts

Question 52

left and right embryonic thoracic ducts gives rise to

Answer 52

left: gives rise to the upper third of the adult thoracic duct right: lower two-thirds of the adult duct

Question 53

the placenta acts as

Answer 53

lung and kidneys

Question 54

Foetal circulation shunts: ductus venosus

Answer 54

shunts blood in left umbilical vein into IVC so oxygenated blood in placenta bypasses liver

Question 55

Foetal circulation shunts: foramen ovale

Answer 55

shunts blood from right atrium to left atrium allows blood to bypass the lungs

Question 56

Foetal circulation shunts: ductus arteriosus

Answer 56

shunts blood from right ventricle and pulmonary arteries to aorta allows blood to bypass the lungs.

Question 57

Closure of foetal shunts & umbilical arteries: ductus venosus

Answer 57

→ligamentum venosum of the liver

Question 58

Closure of foetal shunts & umbilical arteries: foramen ovale

Answer 58

closes after birth →fossa ovalis of the hear

Question 59

Closure of foetal shunts & umbilical arteries: ductus arteriosus

Answer 59

→ligamentum arteriosum between left pulmonary artery and aorta

Question 60

Closure of foetal shunts & umbilical arteries: umbilical arteries

Answer 60

→medial umbilical ligaments of the anterior abdominal wall