Self-Assessment Questions (SAQs) for Study Session 5
Now that you have completed this study session, you can assess how well you have achieved its Learning Outcomes by answering these questions. Write your answers in your Study Diary and discuss them with your Tutor at the next Study Support Meeting. You can check your answers with the Notes on the Self-Assessment Questions at the end of this Module.
SAQ 5.1 (tests Learning Outcomes 5.1, 5.2 and 5.3)
Which of the following statements is false? In each case, say why it is incorrect.
A The energy for moving the sperm’s tail comes from the genetic material in its head.
B Contractions in the muscular walls of the uterus and fallopian tubes assist sperm to move rapidly towards the ovum.
C Implantation occurs when the blastocyst burrows into the endometrium and successfully establishes the early placenta.
D The umbilical vein transports deoxygenated blood from the fetus to the placenta.
E The placenta acts as a filter, preventing the transfer of all harmful substances from the mother to the fetal circulation.
A is false. The energy for moving the sperm’s tail comes from the mitochondria in the structure between the head and the tail.
B is true. Contractions in the muscular walls of the uterus and fallopian tubes assist sperm to move rapidly towards the ovum.
C is true. Implantation occurs when the blastocyst burrows into the endometrium and successfully establishes the early placenta.
D is false. The umbilical vein transports oxygenated blood from the placenta back to the fetus. The deoxygenated blood from the fetus is carried to the placenta by the two umbilical arteries.
E is false. The placenta cannot prevent the transfer of all harmful substances from the mother to the fetal circulation; for example, alcohol and other drugs and chemicals can diffuse through the placenta.
Read Case Study 5.1 and then answer the question that follows it.
Case Study 5.1 Advice for Mrs A after unprotected sex
Mrs A had unprotected sex (without a condom) 17 days after the first day of her last normal menstrual period. She visited your Health Post to ask you if there is a possibility that she could be pregnant.
SAQ 5.2 (tests Learning Outcome 5.2)
Explain the possibilities to Mrs A in language that she can understand.
Mrs A had unprotected sex on day 18 of her menstrual cycle. Ovulation occurs in most women around day 14, so she probably had sex within three to four days after ovulation. The ovum survives for only 12-24 hours unless it is fertilised, so if she ovulated as expected around day 14, then it is unlikely that the ovum was still alive when she had sex on day 18. Therefore, it is unlikely that she will be pregnant this time. But if her ovulation was later than expected, pregnancy is a possibility. Advise her about the risks of unprotected sex in terms of unwanted pregnancy and sexually transmitted infections.
Read Case Study 5.2 about Mrs P, and then answer the question that follows it.
Case Study 5.2 Mrs P asks why alcohol and khat can affect her fetus
Mrs P is a 38-year old pregnant woman who is addicted to alcohol and khat chewing. She attended an antenatal care health education session at your Health Post and listened to your explanation that ‘the maternal blood and fetal blood are not in direct contact’. Following this she asked you ‘Why are you telling me to stop taking alcohol and khat if my blood has no direct contact with my baby’s blood? If my blood has no direct contact, the alcohol and khat will not get into the baby’.
SAQ 5.3 (tests Learning Outcome 5.3)
What is your response? Explain it to her in language that she can understand.
You should explain to Mrs P that although her blood is not in direct contact with that of her baby, the two bloods are very close together in the placenta. Only the thickness of the baby’s blood vessel walls separates them. The walls are so thin that small substances like alcohol and khat can pass through them, from her blood to the baby’s blood. Tell her that this is also how good substances like oxygen and nutrients get into her baby from her own blood, so staying healthy and eating enough food is important for her baby’s development. If she stops taking alcohol and chewing khat, her baby will be much healthier. If she continues taking these harmful substances, the baby could be born with birth defects, or it could even die.
Summary of Study Session 5