Lecture 3

Question 1

What is the age the heart development normally begins in the foetus?

Answer 1

Wk 3 development

Question 2

What do the bulbous cordis, primitive ventricle and primitive atrium eventually become?

Answer 2

Bulbous cordis - right ventricle Primitive ventricle- left ventricle Primitive atrium- left and right atria

Question 3

Describe the pattern of blood flow through the foetal heart:

Answer 3

1. Blood enters the right atrium 2. Right atrium blood goes to the left atrium (via the foramen ovale) 3. Small amount of blood goes from the right atrium to the right ventricle and this is then shunted away from the pulmonary artery to the aorta via the ductus arteriosus

Question 4

Describe the changes to the pattern of blood flow at birth:

Answer 4

1. • Pulmonary circuit pressure decreases, while systemic circuit pressure ultimately increases - Because when oxygen diffuses into blood vessels surrounding the alveoli, the pulmonary arterioles will relax and pulmonary resistance will fall so blood will flow into the lungs 2. Closure of the ductus arteriosus - Pressure changes causes decreased blood flow through the ductus arteriosus - Complete closure 12-24 hours after birth - Physical remanent- ligamentum arteriosum 3. Closing of the foramen ovale - Pressure in the right side of the heart falls- sealing the foramen ovale - Physical remanent- fossa ovalis

Question 5

What occurs in the condition Tetralogy of fallot?

Answer 5

Low oxygenation of the blood this is due to mixing of oxygenated and deoxygenated blood in the left ventricle via the ventricular septal defect

Question 6

What occurs in the condition Persistant right aortic arch?

Answer 6

The right aortic arch fails to regress naturally resulting in entrapment of the oesophagus and trachea at the level of the heart base

Question 7

What is the Truncus arteriosus?

Answer 7

During development the aorta and pulmonary arteries will divide so that blood is not mixing between them

Question 8

What is the bulbar ridges? What will it form

Answer 8

Refers to the cranial end of the bulbus cordis that will eventually give rise to the aorta and the pulmonary trunk with the truncus arteriosus

Question 9

What are the brachial arch arteries?

Answer 9

a series of embryonic vessels derived from the aortic sac

Question 10

Name the structures on this developing embrylogical heart:

Answer 10

1. Sinus venosus
2. Primative atrium
3. Primative Ventricle
4. Bulbus cordis

Question 11

Name the following embryological structures:

Answer 11

1. Sinus venosus
2. Primative atrium
3. Primative ventricle
4. Bulbous cordis
5. Truncus arterisus
6. Sinus venosus
7. Primative atrium
8. Primative ventricle
9. Bulbous cordis
10. Truncus arteriosus
11. Endocardial cushion

Question 12

Name each of the following structures shown below:

Answer 12

1. Septum primum
2. Foramen Primum
3. Endocardial cushions
4. Primative atrium