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ESA 2- Cardiovascular System > Development of the CVS > Flashcards

Flashcards in Development of the CVS Deck (140)
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121

What is the membranous portion of the interventricular septum formed by?

Connective tissue derived from endocardial cushions

122

What does the membraneous portion of the interventricular septum do?

Fills the primary interventricular foramen

123

Where do endocardial cushions appear?

In the truncus arteriosus

124

What happens as endocardial cushions grow?

They twist around each other, forming a spiral septum

125

What is formation of the twisted endocardial cushions dependant on?

Contribution from the neural crest

126

Where does the neural crest migrate from?

Outside of the cardiogenic field

127

What is present before endocardial cushions appear?

A right and left channels

128

What happens to the left and right channels when endocardial cushions appear?

It creates a spiral divisions of the outflow tract

129

What does the spiral division of the outflow tract create?

The ability to separate outflow of the left ventricle from the right ventricle, and divert it to the appropriate site

130

What is the spiral arrangement of the outflow tract the reason for?

The aorta and pulmonary trunk seem to wrap around each other

131

What happens after birth?

Respiration begins, opening the pulmonary circulation

132

What is the result of the opening of the pulmonary circulation?

Left atrial pressure increases, and so forces the foramen ovale closed

133

What happens to the ductus arteriosus after birth?

It contracts in the presence of the higher oxygen saturation

134

What happens to the contraction of the ductus arteriosus over time?

It becomes an anatomical contraction, making this vessel fibrotic

135

What happens when the placental support is removed?

The ductus venous closes as there is no blood flowing through it

136

Why does the foramen ovale close at birth

Because the LA pressure is greater than the RA pressure, so the septum primum is pushed against the septum secundum, and so blood cannot pass through

137

What does the foramen ovale become?

The fossa ovalis

138

What does the ductus arteriosus become?

The ligamentum arteriosum

139

What does the ductus venosus become?

The ligamentum venosum

140

What does the umbilical vein become?

The ligamentum teres