Development of the Cardiovascular System (2.5)

Question 1

When does the formation of the INTERATRIAL SEPTUM happen and what occurs?

Answer 1

FORMATION OF INTERATRIAL SEPTUM (around 33 days - 37 days)

• Septum primum moves down towards the endocardial cushions
• Space between the septum primum and endocardial cushion is foreamen primum
• Perfusions within the foremen primum - in which some fuse
• This forms two gaps called the foremen primum and foremen secundum
• Foremen primum fuses with the endocardial tissue/cushion and closes
• Therefore, the foremen secundum becomes the FORAMEN OVALE

Question 2

What are the features of the CVS in the feotus?

Answer 2

IN THE FEOTUS: Right side high pressure - well oxygenated blood flows through foramen ovale

Question 3

What are the features of the CVS after birth?

Answer 3

AFTER BIRTH: right side low pressure - valve remains closed

The foramen ovale valve eventually fuses to form the fossa ovalis

After birth, respiration begins, causes the LA pressure to increase and causes the closure of the foramen ovale

Question 4

What is the VENTRICULAR SEPTUM comprised of?

Answer 4

MUSCULAR: forms most and grows towards the endocardial cushions and MEMBRANOUS

Gaps within the muscular component of the ventricular septum is filled with membranous parts

Question 5

Explain the development of the AORTICOPULMONARY SEPTUM

Answer 5

AORTICOPULMONARY SEPTUM involves endocardial tissue to grow towards each other and twist

This forms a SPIRAL SEPTUM

Question 6

What are the fetal shunts and what do they form when they close?

Answer 6

Question 7

What are the types of congential heart defects?

Answer 7

CONGENITAL HEART DEFECTS:

• atrial septal defect
• ventricular septal defect
• transposition of great vessels
• tetralogy of fallot
• patent ductant arteriosus

Question 8

What are the types ATRIAL SEPTAL DEFECT?

Answer 8

SECUNDUM ASD - at fossa ovalis (75%)

PRIMUM ASD - lower in position form of AVSD (15-20%)

SINUS VENOSUS ASD - high in atrial septum (5%)

Question 9

What are the VENTRICULAR SEPTAL DEFECT?

Answer 9

ATRIOVENTRICULAR SEPTAL DEFECT: incomplete fusion of endocardial cushions or incomplete membranous portion of the interventricular septum

MEMBRANOUS VSD - more common in males - hole in endocardial cushion

MUSCULAR VSD - Swiss cheese appearance

SUPRACRISTAL VSD - least common

Question 10

What is COARCTATION? What are features of this?

Answer 10

COARCTATION: narrowing of the aorta from the aortic arch to bifurcation

• blood supply to head and neck normal
• upper body hypertension
• weak femoral pulse

Question 11

What is PATENT DUCTUS ARTERIOSUS?

Answer 11

PATENT DUCTUS ARTERIOSUS: persistence of normal fetal vessels that joins the pulmonary artery to the aorta

• should normally close 1 week after birth
• more common in females
• often associated with coarctation and VSD

Question 12

What are the 4 features of Tetrology of Fallot?

Answer 12

FALLOTS TETRALOGY:

VSD - overriding aorta - right ventricular hypertrophy - pulmonary stenosis

It results in TET SPELLS that is caused by drop in oxygen in the blood when the baby cries or eats