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Question 1

Why does the CVS begin to develop at week 3 of embryological development?

Answer 1

The embryo can no longer rely on simple diffusion to receive nutrients

Question 2

What does lateral folding of the trilaminar disc do for the formation of CVS?

Answer 2

Allows them to fuse and create the heart tube

Question 3

What type of folding brings the heart tube into the thorax?

Answer 3

Cephalocaudal

Question 4

What is shown in the image?

Answer 4

The heart tube

Question 5

What is A?

Answer 5

Bulbus Cordis

Question 6

What is B?

Answer 6

Ventricle

Question 7

What two things is section C comprised of?

Answer 7

The atrium and sinus venosus

Question 8

What is D?

Answer 8

The aortic roots

Question 9

What is E?

Answer 9

The truncus arteriosus

Question 10

What is looping driven by?

Answer 10

Expansion of the heart tube

Question 11

How does the cephalic portion of the heart tube loop?

Answer 11

Ventrally, Caudally and to the right

Question 12

How does the caudal portion loop?

Answer 12

Dorsally, cranially and to the left

Question 13

What does looping of the heart tube achieve? (4)

Answer 13

• Primordium of right ventricle closest to outflow tract * Primordium of left ventricle closest to inflow tract * Atrium dorsal to bulbus cordus i.e. inflow is dorsal to outflow * Creates the transverse pericardial sinus \ arteries are in front of the veins

Question 14

What is A?

Answer 14

Outflow tract

Question 15

What is B?

Answer 15

Right ventricle

Question 16

What is C?

Answer 16

Left ventricle

Question 17

What is D?

Answer 17

Atria

Question 18

How does the atrium connect with the ventricle after looping?

Answer 18

Atrioventricular canal

Question 19

What does the atrioventricular canal drive?

Answer 19

Partioning of the heart

Question 20

What does the right atrium develop from?

Answer 20

• Most of the primitive atrium * Absorption of the sinus venosus

Question 21

What does the left atrium develop from?

Answer 21

• Small portion of the primitive atrium * Absorption of the proximal parts of the pulmonary veins (creates oblique pericardial sinus)

Question 22

What does the RA receive venous drainage from?

Answer 22

Receives venous drainage from Vena Cavae

Coronary Sinus

Question 23

Where does the LA receive oxygenated blood from?

Answer 23

receives oxygenated blood from the lungs

Question 24

Another exciting heart for you guys and gals to label What is A?

Answer 24

Superior vena cava

Question 25

What is C? 

Answer 25

Inferior vena cava

Question 26

What is D?

Answer 26

Coronary sinus

Question 27

What is E? 

Answer 27

Pulmonary veins

Question 28

Why does the foetus have two separate circulatory systems? 

Answer 28

Lungs non-functional, so circulation must go through it

Question 29

How does foetus receive oxygen in utero? 

Answer 29

* Receives oxygenated blood from the mother via placenta and umbilical vein  

Question 30

How does foetal circulation differ from developed? 

Answer 30

* Lungs by-passed by foetal circulatory shunts   * Shunt to bypass the right ventricle and lungs

Question 31

Why must some blood be pumped by right ventricle, despite it being useless as lungs not in use?

Answer 31

As muscle must build strength via use

Question 32

What do early arterial systems begin as? 

Answer 32

Early arterial system begins as a bilaterally symmetrical system of arched vessels which then undergo extensive remodelling to create the major arteries leaving the heart.

Question 33

What is the name of the shunt which bypasses lungs after blood has been pumped for right ventricle? 

Answer 33

Ductus arteriosus 

Question 34

What do the right and left 4th arches of the aortic arch become?

Answer 34

* Right 4th arch > proximal part of the right subclavian artery * Left 4th arch > arch of the aorta

Question 35

What do the right and left arches of the 6th arch become? 

Answer 35

* Right 6th arch > right pulmonary artery * Left 6th arch > pulmonary artery & ductus arteriosus

Question 36

What is the nerve corresponding to the sixth aortic arch? 

Answer 36

Reccurent laryngeal nerve 

Question 37

What two factors influence the course of the laryngeal nerve on the right and left side? 

Answer 37

–caudal shift of the developing heart & expansion of the developing neck region –the need for a fetal shunt between PT & aorta