Chapter 13

Question 1

The vascular system appears in the middle of the what week?

a. 2nd
b. 3rd
c. 4th
d. 5th

Answer 1

B

The vascular system appears in the middle of the third week, when the embryo is no longer able to satisfy its nutritional requirements by diffusion alone

Question 2

These cells lie in the epiblast, immediately adjacent to the cranial end of the primitive streak

Answer 2

Progenitor heart cells

Question 3

A horseshoe-shaped cluster of cells cranial to the neural folds forming portions of the atria and the entire left ventricle

Answer 3

Primary heart field (PHF)

Question 4

The right ventricle and outflow tract (conus cordis and truncus arteriosus) are derived from the

Answer 4

Secondary heart field (SHF)

also contributes cells to formation of the atria at the caudal end of the heart

These cells resides in the visceral (splanchnic) mesoderm ventral
to the pharynx

Question 5

Progenitor heart cells migrate through the primitive streak on approximately day

Answer 5

Day 16 of gestation

Question 6

True or False

The laterality of SHF is determined by the same signaling pathway that establishes laterality for the entire embryo

Answer 6

True

This explains the spiraling nature of the pulmonary artery and aorta and ensures that the aorta exits from the left ventricle and the pulmonary artery from the right ventricle.

Question 7

The process of formation of blood cells and vessels

Answer 7

Vasculogenesis

Question 8

Blood islands unite and form a horseshoe-shaped endothelial-lined tube surrounded by myoblasts. This region is known as

Answer 8

Cardiogenic region

Question 9

intraembryonic (primitive body) cavity
over the cardiogenic region later develops into the

Answer 9

pericardial cavity

Question 10

Refers to the pair of longitudinal vessels

Answer 10

Dorsal aortae

Question 11

a key molecule in initiating the pathway of laterality. This is concentrated on the left side of the embryo

Answer 11

Serotonin [5-HT]

Question 12

Serotonin signals this transcription factor that restricts the Nodal expression to the left

Answer 12

MAD3

Question 13

The master gene for the left sidedness

Answer 13

PITX2

Question 14

This period is critical for heart development and individuals with laterality defects

Answer 14

Days 16 to 18

Question 15

A laterality defect where the both the aorta and pulmonary artery exit the right ventricle

Answer 15

Double outlet right ventricle

Question 16

Refers to a right sided heart

Answer 16

Dextocardia

Question 17

A laterality defect wherein both atria or both
ventricles have similar characteristics instead
of the normal left—right differences

Answer 17

Atrial and ventricular isomerisms

Question 18

A laterality defect wherein the characteristics of the atria or ventricles are reversed

Answer 18

atrial and ventricular inversions

Question 19

These are antidepressants that have been linked by epidemiology studies to an increase in heart defects

Answer 19

Selective Serotonin Reuptake Inhibitor

Mechanism: SSRI disrupts 5-HT signaling

Question 20

A fold of mesodermal tissue derived from the SHF

Answer 20

dorsal mesocardium

Question 21

With further development, the middle section of the dorsal mesocardium disappears, creating the

Answer 21

transverse pericardial sinus (connects
both sides of the pericardial cavity)

Question 22

A layer of extracellular matrix rich in hyaluronic acidsecreted by the thickened myocardium

Answer 22

Cardiac jelly

Question 23

Cells from this structure proliferate and migrate over the surface of the myocardium to form the epicardial layer (epicardium) of the heart

Answer 23

Proepicardial organ

The formation of this organ occurs in the mesenchymal cells located at the caudal border of the dorsal mesocardium

Question 24

The three layers of the heart

Answer 24

endocardium
myocardium
epicardium or visceral pericardium

Question 25

The layer of the heart forming its internal endothelial lining

Answer 25

Endocardium

Question 26

which layer forms the muscular wall of the heart

Answer 26

Myocardium

Question 27

It covers the outside of the heart tube

Answer 27

epicardium or visceral pericardium

Question 28

This outer layer of the heart is responsible for the formation of the coronary arteries, including their endothelial lining and smooth muscle

Answer 28

epicardium or visceral pericardium

Question 29

True or False. The lengthening process of the heart tube is essential for normal formation of the left ventricle and the outflow tract region (conus cordis and truncus arteriosus that form part of the aorta and pulmonary artery and for the looping process.

Answer 29

False. The lengthening process of the heart tube is essential for normal formation of the right ventricle

Question 30

As the outflow tract lengthens, the cardiac tube begins to bend on day

Answer 30

23 The cephalic portion of the tube bends ventrally, caudally, and to the right and the atrial (caudal) portion shifts dorsocranially and to the left. This bending, which may be due to cell shape changes, creates the cardiac loop

Question 31

Cardiac tube bending is completed by day

Answer 31

28

Question 32

What portion forms the common atrium and is incorporated into the pericardial cavity

Answer 32

Atrial portion

Question 33

This junction remains narrow and forms the atrioventricular canal

Answer 33

Atrioventricular junction

Question 34

This canal connects the common atrium and the early embryonic ventricle

Answer 34

Atrioventricular canal

Question 35

The bulbus cordis is narrow except for its a. proximal third b. proximal half c. distal third d. distal half

Answer 35

A

Question 36

The proximal third of the bulbus cordis will form the trabeculated part of which ventricle a. left b. right

Answer 36

Right

Question 37

The midportion of bulbus cordis that form the outflow tracts of both ventricles

Answer 37

conus cordis

Question 38

The distal part of the bulbus that form the roots and proximal portion of the aorta and pulmonary artery

Answer 38

truncus arteriosus

Question 39

The junction between the ventricle and the bulbus cordis is externally indicated by

Answer 39

bulboventricular sulcus

Question 40

The junction between the ventricle and the bulbus cordis is called

Answer 40

primary interventricular foramen

Question 41

Which of the following best describes the organization of the cardiac loops by region a. the cardiac tube is organized by regions along its craniocaudal axis from the conotruncus to the left ventricle to the right ventricle to the atrial region respectively b. the cardiac tube is organized by regions along its craniocaudal axis from the conotruncus to the right ventricle to the left ventricle to the atrial region respectively

Answer 41

B

Question 42

When looping is completed, the primitive ventricle, which is now trabeculated, is called the

Answer 42

primitive left ventricle

Question 43

The trabeculated proximal third of the bulbus cordis is called

Answer 43

primitive right ventricle