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19 Cards in this Set

  • Front
  • Back
By what week are all the organ systems complete?
8 weeks (the end of the embryonic period).
what is one of the first systems to become funtional intrauterine.
The cardiovascular system.
how does the circulatory system progress?
From simple blood cells joined to the walls of the yolk sac, to a network of blood vessels, to a single heart tube.
When does the heart begin to beat?
by the end of the 3rd week.
How can the heart beat be heart between the 8th and 12th weeks of pregnancy?
using a doppler system
The heart rate of the fetus is affected by what?
fetal oxygen level and body activity.
what is the blood oxygen saturation level of the fetus?
about 80% that of a newborn.
Why is the rapid rate of fetal heartbeat during pregnancy necessary? (120-160)
to supply oxygen to cells when blood cells are never fully saturated.
lung buds appear on the trachea by the end of what week?
6th week.
Between the ___ and ___ wks.the primitive alveoli form.
16 to 24
how early does the fetus begin to make spontaneous respiratory movements.
11 weeks
at about 24th week of pregnancy, alveolar cells begin to excrete what substance?
surfacant - a phospholipid substance that decreases alveolar surface tension on expiration.
What is the purpose of surfactant?
it prevents the alveoli from collapsing on expiration.
what are the 2 components of surfactant?
lecithin and sphingomyelin
early in the formation of surfactant what is the chief component?
at about 30 weeks there is a surge in the production of what, which becomes the chief component in a ratio of 2:1
what is one of the primary tests of fetal maturity?
analysis of the L/S ratio by an amniocentesis.
When does the nervous system begin to develop?
early, during 3rd week after fertilization. The woman may not even know she is pregnant, and active formation of the nervous system has already begun.
What is quickening?
when baby's movements are strong enough to be felt by the mother. Between 16 and 20 weeks.