49 Fun Facts About Female Anatomy

The human uterus is usually described as being shaped like which fruit?

A pear: it sits just behind and almost over the bladder, which is why a growing pregnancy makes women need to urinate more often.

What is the inner lining of the uterus, shed during a period, called?

Endometrium: each cycle it thickens to receive an embryo, and if none implants, the lining breaks down and leaves the body as a period.

The thick muscular wall of the uterus that contracts during childbirth is called what?

The myometrium: it stretches during pregnancy, letting the uterus grow to several times its usual size before it contracts in labour.

Roughly how many oocytes (immature eggs) are present in the ovaries at birth?

About 1 million: most of them die off naturally, so by puberty well over half are already gone.

Approximately how many eggs does a woman release over her whole reproductive life?

About 400: usually just one egg is released each menstrual cycle, so decades of cycles add up to only a few hundred.

Which test collects cells from the cervix to check for signs of cancer?

Pap smear: it spots precancerous changes before cancer develops, which is how cervical screening helps prevent the disease.

Fertilization normally happens in which part of the fallopian tube, its widest section?

The ampulla: from there, tiny hairs lining the tube sweep the fertilized egg, dividing as it goes, down into the uterus.

What are the finger-like projections at the end of each fallopian tube called?

The egg is actually released into the abdominal cavity first; beating cilia on the fimbriae draw it into the tube.

What is the surgical removal of the uterus called?

Hysterectomy: afterwards periods stop for good, and pregnancy is no longer possible.

What is the median length of the human menstrual cycle?

28 days: yet cycles anywhere from 21 to 35 days long count as normal.

Which day is counted as day one of the menstrual cycle?

The first day of bleeding: pregnancies are dated from it too, so at conception a pregnancy already counts as about two weeks along.

What is the medical term for a girl's first period?

Menarche usually comes before a girl ovulates regularly, which is why early periods are often irregular and can take years to settle.

A surge in which pituitary secretion triggers ovulation?

Luteinizing hormone: home ovulation predictor kits work by detecting this surge in urine.

After ovulation, the follicle's remains form a temporary progesterone gland called what?

Corpus luteum is Latin for 'yellow body'; if no pregnancy begins, it breaks down into a white scar called the corpus albicans.

What are Braxton Hicks contractions?

Practice contractions: they're often mistaken for labour, but unlike real labour they don't build up or come closer together.

When a pregnant woman's waters break, which structure has ruptured?

The amniotic sac: if labour doesn't follow soon after it breaks, doctors usually offer to induce labour because of the risk of infection.

What does IVF stand for?

In vitro fertilisation: eggs are fertilised in a lab and the embryo placed in the womb, getting round problems such as blocked or damaged fallopian tubes.

What does the medical term 'amenorrhoea' mean?

Absence of periods: it is normal in pregnancy and breastfeeding, but can also follow sudden weight loss or too much exercise.

What happens to a woman's resting body temperature just after ovulation?

It rises slightly: progesterone released after ovulation lifts it, which is why fertility-awareness methods record temperature every day.

What does it mean when a baby is breech late in pregnancy?

Bottom or feet first: from about 36 weeks, a doctor may try to turn the baby head down by pushing on the mother's belly, a procedure called ECV.

Which condition becomes more likely after menopause, as bone loss speeds up?

Osteoporosis: it can weaken bones so much that even a minor fall, which a healthy bone would withstand, causes a fracture.

The hot flushes of menopause are mainly linked to falling levels of which hormone?

Estrogen: hormone replacement therapy, which supplies it again, can relieve the flushes.

Which bone is the most sexually dimorphic in the human skeleton, and so most reliable for determining sex from remains?

The pelvis: a woman's is larger and broader, a trade-off between efficient walking and a birth canal wide enough for a baby's head, as the obstetrical dilemma hypothesis proposes.

Which skin condition, nicknamed the 'mask of pregnancy', causes dark patches on the face?

Melasma: sunlight can darken the patches or bring them back after they fade, so protecting the skin from the sun matters.

What is the most common cause of heavy bleeding just after childbirth?

The uterus failing to contract: after birth its muscle normally clamps shut the blood vessels where the placenta was attached.

Which mineral are women with heavy periods most at risk of running low on?

Iron: blood lost each period carries iron with it, and heavy periods and pregnancy are very common causes of iron deficiency anaemia.

What is usually the first physical sign of puberty in girls?

Breast budding: it usually begins between 8 and 13, so signs of puberty before 8 can mean early puberty, which a GP can check.

What is the medical term for the onset of breast development at puberty?

In the two years after it, the uterus, ovaries and follicles all grow; menarche follows later.

Besides connective tissue, which two tissue types make up the breast?

Adipose and glandular: breasts with more glandular tissue look denser on a mammogram, where tumours can be harder to spot.

The suspensory bands that support the breast are named after which English surgeon?

Cooper: Sir Astley Cooper, who described the ligaments in 1840, had removed a cyst from King George IV's scalp and was made a baronet.

What is the name of the pigmented area of skin surrounding the nipple?

The areola: its small Montgomery glands release an oil that protects the skin during breastfeeding.

What is colostrum?

An early form of breast milk: thick and golden yellow, colostrum carries antibodies that help protect a newborn against infection.

Which hormone is the main driver of milk production during breastfeeding?

Prolactin: high levels while breastfeeding are linked to suppressed ovulation, one reason exclusive breastfeeding can delay periods returning.

Which hormone contracts the cells around the milk-producing alveoli in the "let-down" reflex?

Oxytocin: a synthetic version is given through a drip to start or speed up labour.

Pre-eclampsia in pregnancy is marked mainly by a new rise in what?

Blood pressure: it often comes with protein in the urine, and it usually eases only once the baby and placenta are delivered.

During childbirth the cervix must dilate to more than what diameter?

10 cm: that is roughly how wide the opening must be for a full-term baby's head to pass through.

Around ovulation, cervical mucus becomes thin and more what, to help sperm survive?

Alkaline: the thinner mucus also turns stretchy, a quality called Spinnbarkeit, which lets sperm enter the uterus.

The word 'vagina' comes from the Latin for what?

A sheath or scabbard: the Romans never used the word for anatomy; it entered English medicine only in the 1680s.

Which bacteria dominate a healthy vagina and keep it acidic?

Lactobacilli: their lactic acid holds germs in check, and when the natural balance of bacteria shifts, bacterial vaginosis can follow.

What do Bartholin's glands produce?

Lubricant: the glands secrete mucus that moistens the vagina, and if a gland's opening gets blocked, fluid builds up into a painful Bartholin's cyst.

Skene's glands are sometimes called the 'female' version of which male organ?

The prostate: like it, Skene's glands produce prostate-specific antigen, the protein PSA blood tests measure to screen for prostate cancer.

What does the medical term 'mittelschmerz' describe?

Ovulation pain: the word is German for 'middle pain', because it strikes around the middle of the menstrual cycle.

A Barr body, seen in the cells of females, is what?

An inactivated X chromosome: Murray Barr and his student spotted it in 1949, and in 1961 Mary Lyon explained that one X in each female cell is switched off.

Which hormone, produced after implantation, do home pregnancy tests detect?

Human chorionic gonadotropin: cells around the growing embryo make it after implantation, so a test taken too early may give an unreliable result.

The word 'placenta' comes from a Latin word for what, referring to the organ's shape?

A flat cake: if the placenta attaches low and covers the cervix, called placenta praevia, the baby usually has to be born by caesarean.

Roughly how much does a full-term human placenta weigh?

About 500 grams: it lets oxygen and nutrients pass between mother and baby without their bloodstreams ever mixing.

About how big is a typical non-pregnant adult uterus?

A fist: in pregnancy it grows so much that it can push the stomach muscles apart, often leaving a gap after the birth.

Which condition occurs when a fertilised egg implants outside the womb, usually in a fallopian tube?

An ectopic pregnancy cannot be saved, and if the tube ruptures it can be life-threatening, though that is uncommon and treatable if caught quickly.

What is an episiotomy, sometimes done during childbirth?

A cut widening the vaginal opening: it can help prevent a severe tear, or speed up the birth when the baby needs to be born quickly.