Human Fertility Trivia Quiz

Answer: Regulates sperm production

In men, FSH acts primarily on Sertoli cells, the "nurses" of the baby sperm cells, found in the testes. There, it helps support the development of sperm by promoting Sertoli cell proliferation and function, creating a happy environment for the little germ cells. Meanwhile, testosterone, which is stimulated by luteinizing hormone (LH), certainly plays a major role as well.

The division of labor in the testes is fairly simple, which is why most of this quiz is about women. FSH works through Sertoli cells, while LH that tells Leydig cells to make testosterone. FSH also helps Sertoli cells produce various substances that nourish and support developing germ cells.

In men, reduced FSH activity can cause relatively mild reductions in sperm production or much more serious problems, depending on the actual underlying cause.

Answer: False

The epididymis is where sperm undergo maturation. The sperm are actually produced in the seminiferous tubules inside the testes. Newly formed sperm leave the testes and enter the epididymis, where they spend time getting fine-tuned until they're able to move and fertilize an egg. So the epididymis is more of finishing room than the actual factory floor.

Answer: Causes ovarian follicle growth

FSH is what gets things rolling in the ovaries during the follicular phase of the menstrual cycle. It acts on granulosa cells inside the ovaries that surround developing ovarian follicles, little egg sacs in the ovaries, and stimulates follicular growth and maturation.

As the follicle develops, the immature egg inside it progresses toward maturity. Several follicles grow, and then the race is on! The first follicle to finish its job gets the honor of releasing a mature ovum that month. If more than one matures and releases an egg, you might be needing another crib or two.

Answer: Estrogen

As ovarian follicles develop during the follicular phase, their granulosa cells produce increasing amounts of estradiol. That's the primary form of estrogen during a woman's reproductive years. Rising estrogen causes the uterine lining (endometrium) to rebuild and thicken after menstruation.

FSH helps drive follicle development and, through its effects on granulosa cells, supports estrogen production. Progesterone becomes the major hormone after ovulation, when the ruptured follicle transforms into the corpus luteum. We'll get to that in another question.

Answer: Ovulation

The LH surge is the hormonal trigger that makes the magic happen, if by magic you mean ovulation. After the hormonal surge begins, a mature ovarian follicle undergoes changes and its walls weaken. Eventually it ruptures and releases the ovum. The timing is not instantaneous, though. Ovulation generally occurs about 10 to 12 hours after the LH peak, which in turn is about 36 hours after the surge begins.

The LH surge also causes granulosa and theca cells to form a temporary structure (corpus luteum) that will keep making hormones during a woman's luteal phase. If pregnancy occurs, the corpus luteum will support pregnancy until the placenta takes over in a couple of months.

Answer: Resting heart rate decreases significantly

A slight rise in basal body temperature is a well-established sign that ovulation has occurred. This is mainly caused by the increase in progesterone after ovulation. Breast tenderness and bloating are also commonly reported around ovulation, although not all women experience them.

Resting heart rate, on the other hand, does not decrease as a sign of ovulation. There is some evidence that heart rate can change across the menstrual cycle, although it typically increases slightly around this time because of the release of progesterone.

Answer: Secretory phase

During the secretory phase, progesterone from the corpus luteum, that temporary structure created in the ovary during the LH surge, works on the previously thickened endometrium, causing it to grow more blood vessels. This change brings more blood and nutrients (like glycogen) to the area, making it receptive to an embryo. This phase follows ovulation.

The proliferative phase comes before ovulation and is driven mainly by estrogen from developing ovarian follicles. We talked about that earlier. During that phase, the endometrium regenerates and thickens. Once ovulation has occurred, progesterone takes over the heavy work, adding the final touches to make the uterus a cozy place for a blastocyst to implant itself.

Answer: The cervix will move lower in the pelvis

As fertility approaches and estrogen levels rise, the cervix generally moves higher in the vagina, becomes softer, and opens slightly. Meanwhile, cervical mucus becomes thinner, wetter, and more slippery, creating just the right conditions for sperm cells to make their final battle charge.

The position change is particularly useful because the fertile cervix is generally described as high, soft, and open. Outside the fertile period, it tends to be lower, firmer, and more closed. The mucus changes along a similar timetable, going from thicker and less hospitable to sperm-friendly, slippery fluid as ovulation approaches.

Answer: Mittelschmerz

Mittelschmerz is the medical term for pain that occurs around ovulation. It's usually felt in the lower abdomen or pelvis and often on the side of the ovary releasing an egg. So I'm told. If you can't guess, the word comes from German: "mittel" means middle and "schmerz" means pain. So, "middle pain." The discomfort may be a bit of a twinge or an ache, but it can sometimes be sharper.

It can last a few minutes to a day or two. Nobody is sure exactly what causes it, but it's believed that the stretching and rupturing of the ovarian follicle may contribute.

Answer: True

A mature human ovum is unusually large for a human cell, measuring roughly 100 to 140 micrometers in diameter. That puts it at the threshold of naked-eye visibility, so under suitable conditions an isolated egg can be seen without a microscope. It is not exactly going to leap out at you, though. It's about the width of a human hair.

For comparison, many human cells are only around 10 to 20 micrometers across, with a sperm cell (whose head is only about 2.5 micrometers wide) being completely dwarfed by the giant it's trying to conquer.