Sexual Reproduction in Humans：练习题

What is the primary function of the amniotic fluid surrounding the developing fetus?

If the progesterone levels in a woman remain high after day 21 of her menstrual cycle, what is the most likely reason?

If the progesterone level remains high and does not drop at the end of the menstrual cycle, what is the most likely reason?

Which hormone is primarily responsible for the repair and thickening of the uterine lining (endometrium) after menstruation?

Which substance moves from the maternal blood to the fetal blood across the placenta?

State the function of the amniotic fluid during pregnancy.

Identify the fertile phase of the menstrual cycle in a typical 28-day cycle and explain why it occurs then.

Discuss why the fertile phase of the menstrual cycle is usually considered to be around day 11 to day 17, assuming a 28-day cycle.

(a) What does the acronym HIV stand for?
(b) List two common methods by which HIV can be transmitted from one person to another.

Describe the sequence of events that occur from fertilisation to implantation in the human female reproductive tract. Use the term 'ball of cells' in your explanation.