Cardiovascular Development

Question 1

How does the mesoderm develop?

Answer 1

Paired endocardial tubes in the mesoderm fuse into a single tube.

The single tube enlarges to from the myocardial mantle

Starts beating ~22 days

It grows and bugles anteriorly in the pericardial activity

Question 2

The endocardial tube and myocardium subdivide into ___ (number) regions.

What are they called?

Answer 2

5

Aortic sac
Bulbus cordis
Ventricle
Primitive atrium
Sinus venouses

Question 3

Describe what the following features in an embryo form into as an adult:

Bulbus Cordis ->
Ventricle->
Primitive Atrium->
Sinus venouses->

Answer 3

Bulbus Cordis-> Aorta and pulmonary artery

Ventricle-> Left Ventricle

Primitive Atrium-> R & L auricles and L atrium

Sinus venouses-> R atrium, Vena cavae & coronary sinus

Question 4

Flow of blood through embryonic heart BEFORE septation

Answer 4

Question 5

What are the 4 steps of development of 4-chambered heart?

Answer 5

1. Sinus venosus and primitive atrium divides into right & left atria.
2. Primitive ventricle separates from bulbus cordis to form left and right ventricles.
3. Primitive atrium is separated from the primitive ventricle.
4. Conus cordis and truncus arteriosus develop internal partitions to become the proximal aorta and pulmonary trunk.

Question 6

The primitive atrium is divided into what?

Answer 6

R & L atria

Question 7

Patent Foramen Ovale (PFO)

Answer 7

Hole between upper L & R chambers naturally in fetus and will close once born

If it does NOT, it is known as PFO

Question 8

What happens in Patent Foramen Ovale is not fixed?

Answer 8

Asymptomatic (probe-patent) foramen ovale have been reported in up 25% of the normal population

May open during increased right heart pressure

Can allow clots to enter the arterial circulation (stoke)

Question 9

The primitive ventricle and bulbis cordis are initially separate by ______________________.

Answer 9

muscular portion of inter-ventricular septum

(also helps separate atrioventricular canal into R and L canals)

Question 10

What separates the two ventricles?

What forms the membranous portion of this?

Answer 10

Interventricular septum

Endocardial cushions form the membranous portion of the septum
(also contributes to pulm & aortic valves)

Question 11

What does mesenchyme help form?

Answer 11

It hollows out and leaves chordae tendinae and papillary muscles

Question 12

What is Tetrology of Fallot?

Answer 12

birth defect that affects normal blood flow through the heart

Question 13

What are the 4 steps of Tetrology of Fallot

Answer 13

Pulmonary stenosis
Right ventricular hypertrophy
Overriding aorta
VSD

Question 14

The conus cordis and truncus arteriosis form what?

What subdivides this structure?

Answer 14

A single tube leading to the aortic sac; which is subdivided by spiral conotruncal ridges

Question 15

Coarctation of the aorta is what?

Answer 15

birth defect in which a part of the aorta is narrower than usual

Can occur anywhere from the transverse arch to the iliac bifurcation

Question 16

What signs will Coarctation of the Aorta show?

Answer 16

Mild forms are asymptomatic

Severe obstruction can lead to lower body hypoperfusion and/or heart failure

Question 17

For development of veins, initially they all empty into what?

Answer 17

Sinus venouses

Question 18

Vitelline veins contain what?

Answer 18

Deoxygenation blood from yolk sac

Question 19

Cardinal veins contain what?

Answer 19

Deoxygenation blood form the embryo itself

Question 20

Umbilical veins contain what?

Answer 20

Oxygenation blood from the placenta

Question 21

Malformation of cardinal veins result in what?

Answer 21

abnormal venous drainage