Cardiovascular (CV) system

Question 1

It induces the precardiac mesoderm to form vascular channels that ultimately form the endocardial tube (endocardium)

Answer 1

Vascular endothelial growth factor (VEGF)

Question 2

Mesoderm migrating into the cardiac region from the coelomic wall near the liver forms the____

Answer 2

Epiderm

Question 3

The pericardial cavity is derived from___

Answer 3

Lateral plate mesoderm. Lat. plate mesoderm at the cephalic area of the embryo wall split into a somatic layer and splanchnic layer forming the pericardial cavity.

Question 4

What are the 5 primitive heart tube dilations?

Answer 4

1. Truncus arteriosus
2. Bulbus cordis
3. Primitive ventricle
4. Primitive atrium
5. Sinus venosus

Question 5

What is the 1st step of the development of conduction system of the heart?

Answer 5

1. At week 5, cardiac myocytes in the sinus venosus region of the primitive heart tube begin to undergo spontaneous electrical depolarization at a faster rate than cardiac myocytes in other regions.

Question 6

What is the 2nd step of the development of the conduction system of the heart?

Answer 6

2. As dextral looping occurs, the sinus venous becomes incorporated into the rt. atrium, and these fast-rate depolarizing cardiac myocytes become the SA node and the AV node

Question 7

What is the 3rd step of the development of the conduction system of the heart?

Answer 7

3. In the adult, the cardiac myocytes of the SA and AV nodes remain committed to a fast rate of electrical depolarization instead of developing contractile properties.

Question 8

What is the 4th step of the development of the conduction system of the heart?

Answer 8

4. As the atria and ventricles become electrically isolated by the formation of the fibrous skeleton of the heart, the AV node provides the ONLY pathway for depolarization to flow from the atria to the ventricles

Question 9

What is the 5th step of the development of the conduction system of the heart?

Answer 9

The bundle of His develops from a ring like cluster of cells found at the AV junction that specifically expresses the msx2 homeobox gene.

Question 10

What is the 6th step of the development of the conduction system of the heart?

Answer 10

The purkinje fibers develop from already contractile cardiac myocytes w/in the myocardium and can therefore be considered as modified cardiac myocytes.

Question 11

What is the correct order of conduction system of the heart:

1. SA node develops
2. AV node develops
3. Bundle of His develops
4. Purkinje fibers develop

A. 1, 2, 3, 4
B. 1, 3, 2, 4
C. 2, 4, 3, 1
D. 4, 3, 2, 1
E. 1, 4, 3, 2

Answer 11

A. 1, 2, 3, 4

1. SA node develops
2. AV node develops
3. Bundle of His develops
4. Purkinje fibers develop