Neonatal Adaptations & Placenta Flashcards
What happens to the ductus arteriosus after birth?
It becomes the ligamentum arteriosum
What happens to the foramen ovale after birth?
it becomes the fossa ovalis
What happens to the umbilical arteries and veins after birth?
The umbilical cord contains 2 arteries and 1 vein
The vein becomes the ligamentum teres
The arteries become the medial umbilical ligaments
What happens to the ductus venosus after birth?
It becomes the ligamentum venosum
What is the state of the baby’s lungs at birth?
They are fluid filled
What happens when the baby takes its first breath?
When does this occur?
This occurs within 10 seconds of delivery
There is a fall in pulmonary vascular resistance
This increases blood flow to the lungs and increases the surface area for gas exchange
What happens to the flow of oxygenated blood once the baby takes its first breath?
Oxygenated blood reaches the left atrium and ventricle
It passes through the descending aorta to reach the umbilical arteries
How does oxygenated blood affect the umbilical arteries?
it stimulates constriction of the umbilical arteries
This results in a reduction in placental blood flow, which ceases completely after about 3 minutes
What is the result of an increased pulmonary venous return?
Closure of the foramen ovale and ductus arteriosus
How does haemoglobin change after birth?
The change to adult B-Hb takes several weeks
The gamma chains change to beta chains
What are the 5 main functions of the placenta?
- nutrition
- excretion
- immunity
- endocrine
- defence
How does the placenta provide nutrition and excretion?
It transfers nutrients and oxygen to the foetus
It removes CO2 and waste products
How does the placenta provide immunity?
It transfers antibodies to provide protection from infections
How does the placenta have an endocrine function?
- manufacture of steroid hormones - oestrogen and progesterone
- manufacture of human placental lactogen
- manufacture of human chorionic gonadotrophin
how is the placenta involved in defence?
It protects the foetus from the mother’s immune system
