Video Transcript
Complete the table to describe the
key events that take place in a typical 28-day menstrual cycle.
In order to answer this question,
first we’ll recall the events that occur during a typical menstrual cycle. And then we’ll use that information
to complete the table provided. The menstrual cycle is a series of
events that occur within the female reproductive system, approximately once every 28
days in preparation for possible pregnancy. Here we’ve drawn a little diagram
of the female reproductive system. It includes the vagina and its
external features; the uterus, also referred to as the womb; the cervix, which is
the opening between the vagina and the uterus; the ovaries, which contain the female
gametes or egg cells; and the fallopian tubes, which connect the ovaries to the
uterus.
About once a month, an egg cell
erupts from the ovary and travels down the fallopian tube. While that’s occurring, a lining
rich in blood vessels is building up within the uterus. If the egg cell is fertilized by a
sperm cell, it will implant into this lining and pregnancy will begin. Otherwise, the egg cell breaks
down. The unnecessary uterine lining also
breaks down, and it is shed through the vagina in a process known as
menstruation. Then the cycle begins all over
again. This is what we call the menstrual
cycle, and it typically takes about 28 days to occur.
The first day of the menstrual
cycle is marked by the first day of menstruation or the shedding of the uterine
lining through the vagina. Typically called a period,
menstruation lasts about five days. In the days after menstruation, the
uterus lining begins to build up again in preparation for possible pregnancy. About halfway through the menstrual
cycle, ovulation occurs and the egg cell is released from the ovary into the
fallopian tube. After ovulation, the uterus lining
is maintained. If the egg cell has been
fertilized, it will implant into the uterus lining during this time. If not, the uterus lining will be
shed during menstruation and the entire cycle will begin again.
So now we’re ready to complete our
table. The event at the beginning of the
menstrual cycle is menstruation. The event about halfway through on
day 14 is ovulation. And between menstruation and
ovulation, the uterus lining is building up.
