pregnancy

• what is the defined timeframe for pregnancy

  the first day of the last period until birth
• what is the average pregnancy in weeks

  39 weeks
• What is the amniotic sac?

  It is the fluid-filled, bag-like membrane in which the fetus develops.
• where is the amniotic sacs membrane derived from

  blastocyst
• what are the roles of the amniotic fluid

  maintains fetal temperature, acts as a shock absorbed to protect the fetus
• where does the placenta form

  between the tissues of the mother and the fetus
• how is the placenta connected to the fetus

  by the umbilical cord
• what two blood vessels are found in the placenta

  umbilical artery and umbilical vein
• what is the function of the umbilical vein

  Carries blood containing oxygen and glucose to the fetus from the placenta
• what is the function of the umbilical artery

  carries blood containing carbon dioxide away from the fetus
• where are fetal capillaries found

  within the chorionic villi
• what is the chorionic villi

  the boundary between maternal and fetal blood
• where does the blood from the maternal arterioles empty

  into the intervillous space
• why is there a shorter diffusion pathway for material from the mother to the baby

  there are no maternal capillaries between the maternal arteriole and the maternal venule so there is one less layer
• in what direction does the blood int he fetus and in the mother flow

  counter current flow
• what are the 4 roles of the placenta

  exchange of materials ,to provide protection, to protect eh foetus and t allow the passage of maternal antibodies
• what materials are exchanged into the fetus

  glucose , oxygen , amino acids and slats
• what materials are exchanged out of the fetus

  carbon dioxide and nitrogenous waste
• what will the placenta need to provide protection from

  the mother immune system
• what will the placenta need to protect the fetus from

  the difference in blood pressure
• what does the placenta allow to get antibodies to the fetus

  passive immunity