3.1.6 Pregnancy Flashcards
After fertilization in the oviduct, where does the zygote travel?
the zygote travels towards the uterus, this usually takes about 3 days, during which time the zygote will divide several times to form a ball of cells known as an embryo.
Once the zygote reaches the uterus, where does the embryo embed itself?
in the thick lining of the uterus (a process known as implantation) and continues to grow and develop
Where does the placenta form?
where the embryo is attached
The placenta is an organ that ensures materials can be exchanged between, what?
the blood of the mother and the blood of the growing embryo
What is the role of the umbilical cord
The umbilical cord joins the embryo’s blood supply to the placenta for the exchange of nutrients and removal of waste products
The embryo is surrounded by what type of fluid?
amniotic fluid (a fluid made from the mother’s blood plasma) that is held in by the amniotic membrane (also known as the amniotic sac)
What is the gestation period
It is the 9 months of growth in the uterus
Major development of organs takes place within, how long?
within the first 12 weeks, during which time the embryo gets nutrients from the mother by diffusion through the uterus lining.
After this point, the organs are all in place, the placenta has fully formed and the embryo is now called a fetus (sometimes spelled fetus). The remaining gestation time is used by the fetus to grow bigger in size
During the gestation period, the fetus develops and grows by gaining all the:
glucose, amino acids, lipids, water, oxygen, mineral ions, and vitamins it needs from the mother’s blood
How close does the mother’s blood come into proximity with the blood of the fetus
the mother’s blood comes into very close proximity to the blood of the fetus but never mixes with it
The fetus’s blood connects to and from the placenta by the:
umbilical cord
What does the mother’s blood absorb from the fetus’s blood in the placenta
the waste products; substances like carbon dioxide and urea are removed from the fetus’s blood so that they do not build up to dangerous levels
The movement of most molecules across the placenta occurs by:
diffusion due to the difference in concentration gradients, for some substances that need to be moved, active transport may be involved
The placenta is adapted for this diffusion by having a large surface area and a thin wall for efficient diffusion
The placenta acts as a barrier to prevent what?
The placenta acts as a barrier to prevent toxins and pathogens from getting into the fetus’s blood
Why are women advised to not smoke during pregnancy?
molecules like nicotine can pass across the placenta
