Development of the Cardiovascular System

Question 1

With what structure does the formation of the heart begin?

Answer 1

Primitive heart tube

Question 2

What are the six regions of the primitive heart tube, from superior to inferior?

Answer 2

Aortic roots
Truncus arteriosus
Bulbus cordis
Ventricle
Atrium
Sinus venosus

Question 3

For what is the sinus venosus responsible in the developing heart?

Answer 3

Inflow of blood to primitive heart
Empties into primitive atrium
Drains right and left sinus horns

Question 4

What does the left sinus ultimately form in the heart?

Answer 4

Coronary sinus

Question 5

What does the right sinus form the cardiovascular system?

Answer 5

Part of inferior vena cava

Question 6

What are the derivatives of the first aortic arch?

Answer 6

Contributes to

• Maxillary artery
• Hyoid artery
• Stapedial artery

Question 7

What are the derivatives of the second aortic arch?

Answer 7

Contributes to

• Maxillary artery
• Hyoid artery
• Stapedial artery

Question 8

What are the derivatives of the third aortic arch?

Answer 8

Common carotid artery

Part of proximal internal carotid artery

Question 9

What are the derivatives of the fourth aortic arch?

Answer 9

Right arch forms right subclavian artery

Left arch forms part of arch of aorta

Question 10

What are the derivatives of the fifth aortic arch?

Answer 10

Never forms/forms incompletely and regresses

Question 11

What are the derivatives of the sixth aortic arch?

Answer 11

Right arch forms right pulmonary artery
Left arch forms
- Left pulmonary artery
- Ductus arteriosus

Question 12

With which nerve is the sixth aortic arch associated?

Answer 12

Recurrent laryngeal nerve

Question 13

What is the process of septation in the atria?

Answer 13

Septum primum forms, splitting atrium into 2
Ostium primum = hole present before septum primum completes fusion
Ostium secondum appears in septum primum > ostium primum closes
Septum secundum grows with foramen ovale inside

Question 14

What does the foramen ovale (and other holes within septum of atria) allow?

Answer 14

Shunting of blood from right to left side of heart, bypassing lungs

Question 15

How does the interventricular septum form?

Answer 15

Muscular part grows up out of floor of ventricles towards endocardial cushions
Primary interventricular foramen filled by membranous part - grows down from endocardial cushions

Question 16

What divides the outflow tract of the heart into left and right sides?

Answer 16

Spiral septum

Question 17

What shunts bypass the lungs in foetal circulation?

Answer 17

Foramen ovale between atria - main shunt

Ductus arteriosus between pulmonary trunk and arch of aorta

Question 18

What shunts bypass the liver in foetal circulation?

Answer 18

Ductus venosus between umbilical cord and inferior vena cava

Question 19

How does the foramen ovale close at birth?

Answer 19

Intake of air > pulmonary resistance falls > pressure in left atrium higher than right > blood can’t flow left to right in foramen ovale > fused by age 1 year

Question 20

How does the ductus arteriosus close at birth?

Answer 20

Muscular wall contracts, mediated by bradykinin

Question 21

What is the adult remnant of the foramen ovale?

Answer 21

Fossa ovalis

Question 22

What is the adult remnant of the ductus arteriosus?

Answer 22

Ligamentum arteriosum

Question 23

What is the adult remnant of the ductus venosus?

Answer 23

Ligamentum venosum

Question 24

What is the adult remnant of the umbilical vein?

Answer 24

Ligamentum teres