CVS: heart field, heart tube , cardiac looping

Question 1

Which organ found in human embryo is first organ to function?

Answer 1

heart

Question 2

heart begins…:
1. beating ?
2. pumping blood by ?

Answer 2

1. early as 21st day of development
2. day 24-25

Question 3

heart is an ..1.. organ whose ..2… patterning is established during ..3…

Answer 3

1. asymmetrical
2. left-right
3. gastrulation

Question 4

most of the CVS is derived from which germ layer ?

Answer 4

lateral plate (splanchnic) /visceral mesoderm

Question 5

In response to signals from endoderm, ectoderm and midline mesoderm what forms within the lateral (splanchnic) mesoderm at the cranial end of the embryo ?

Answer 5

cardiac primordium , called the cardiac crescent, or first heart field

Question 6

what do cardiac progenitor cells develop into ?

Answer 6

cardiac myoblasts

Question 7

What do blood islands undergo to form vascular structures ?

Answer 7

vasculogenesis

Question 8

first heart field is initially ..1.. shaped and surrounded by ..2…

eventually it will give rise to ..3… and the ..4..

Answer 8

1. horsehoe
2. cardiac myoblasts
3. left ventricle
4. atria

Question 9

what is named the second heart field (SHF) ?

Answer 9

multipotent progenitor cells that have been identified in pharyngeal mesoderm

Question 10

what does the second heart field give rise to ?

Answer 10

right ventricle & outflow tract (eventually develop into direct blood away from heart e.g. aorta + pulmonary tract)

Question 11

Primary heart tube consists of a ..1.. tube with ..2.. mesoderm differentiating into ..3.. that will form …4…

Answer 11

1. single endocardial
2. adjacent
3. cardiomyocytes
4. myocardium

Question 12

Developing myocardium deposits a layer of acellular ..1.. matrix, the ..2…, that separates it from the ..3..

Answer 12

1. extracellular
2. cardiac jelly
3. endocardial tube

Question 13

where is the primary heart tube initially suspended ?

Answer 13

In the developing pericardial cavity by a dorsal mesocardium located beneath the foregut

Question 14

what is the dorsal mesocardium also known as ?

Answer 14

dorsal mesentery of the heart

Question 15

What happens to the heart when the dorsal mesocardium ruptures over almost the entire length of the heart tube ?

Answer 15

the heart is left suspended in the pericardial cavity by its developing arterial and venous poles,

whilst the ruptured dorsal mesocardium becomes the transverse pericardial sinus within the pericardial sac of the definitive heart

Question 16

what happens to the ruptured dorsal mesocardium when the dorsal mesocardium ruptures over almost the entire length of the heart tube and the heart is left suspended in the pericardial cavity ?

Answer 16

it becomes the transverse pericardial sinus within the pericardial sac of the definitive sac

Question 17

heart tube wall consists of ?

Answer 17

1. endocardium
2. cardiac jelly
3. myocardium
4. epicardium

Question 18

What are the regions of the primary heart tube ?
Arterial end -> venous end

Answer 18

Arterial end -> venous end
1. aortic roots
2. Truncus arteriosus
3. conus cordis
4. proximal 1/3
5. primitive ventricle
6. primitive atrium
7. sinus venosus

Question 19

Bulbus cordis consists of what ?

Answer 19

• truncus arteriosus
• conus cordis
• proximal 1/3

Question 20

sinus venosus develops into ?

Answer 20

posterior portion of the right atrium, the SA node and the coronary sinus

Question 21

primitive atrium develops into ?

Answer 21

trabeculated parts of right and left atria

Question 22

primitive ventricle develops into ?

Answer 22

trabeculated part of left ventricle

Question 23

bulbus cordis develops into ?

Answer 23

• trabeculated part of right ventricle
• outflow part of both ventricles (distal part)

Question 24

truncus arteriosus divides and gives rise to … ?

Answer 24

ascending aorta and pulmonary trunk

Question 25

where is bulboventricular sulcus (interventricular septum) found in the primary heart tube ?

Answer 25

between the proximal 1/3 of bulbus cordis and primitive ventricle

Question 26

what happens day 23 (week 4) to the primary heart tube ?

Answer 26

it begins to elongate and simultaneously bend and twist into a C-shaped structure with the bend extending towards the right side: the ventral surface of the primary heart tube forms forms the right outer curvature of the C-shaped heart

Question 27

when does the heart tube take the S-shaped configuration ?

Answer 27

it continues to elongate at both arterial and venous poles

Question 28

In process of heart tube taking S-shaped configuration what happens ? to the following: 1. primitive right ventricle 2. primitive left ventricle 3. primitive atrium

Answer 28

1. displaced caudally, ventrally and to the right 2. displaced to the left 3. it acquires a more dorsal and cranial position

Question 29

What is the end result of cardiac looping ?

Answer 29

to bring the 4 presumptive chambers of the future heart into their correct special relationship: * atrium -> dorsal & cranial * ventricle -> displaced left * bulbus cordis -> moves inferiorly , ventrally to the right

Question 30

by which day is the elongation of the heart tube is complete ?

Answer 30

28

Question 31

what does the atrioventricular junction develop into ?

Answer 31

atrioventricular canal which connects the primitive atrium and the primitive ventricle

Question 32

what develops into the primary interventricular foramen ?

Answer 32

bulboventricular sulcus between the ventricle and bulbus cordis

Question 33

Name 3 abnormalities associated with cardiac looping

Answer 33

* ventricular inversion * heterotaxy * visceroatrial heterotaxy syndroms

Question 34

ventricular inversion is a condition in which ...?

Answer 34

looping of the heart tube is reversed from its normal sinistral (left) pattern

Question 35

what does ventricular inversion result in ?

Answer 35

a heart that has its apex inferior to the right side (rather than the left)

Question 36

what is heterotaxy as a condition ?

Answer 36

a congenital condition ascribed to abnormal left-right axis formation

Question 37

2 froms of heterotaxy ?

Answer 37

partial situs ambiguous and situs inversus totalis * partial situs ambiguous (a verseral of some organs) * or situs inversus totalis (reversal of all visceral) * a few if any symptims

Question 38

what are visceroatrial heterotaxy syndromes ?

Answer 38

conditions where the abdominal viscera and the atrial pole are oriented on opposing sides of the body

Question 39

What structural defects are associated with visceroatrial heterotaxy syndromes?

Answer 39

* A common atrium * Malalignment of the atrioventricular canal and outflow tract * Abnormal venous and arterial vascular connections