Which one of the following is not a part of the male reproductive system in human beings?

Correct — C, Cervix. The cervix is the neck of the uterus — its narrow lower portion, opening into the vagina — and it belongs entirely to the female reproductive system. During childbirth it is the structure that dilates to let the baby pass, and it is the site sampled in a cervical screening test. Nothing corresponding to it exists in the male body. The other three are all male organs, and together they trace most of the male system. The testes are the paired gonads that make both sperm and the hormone testosterone. The scrotum is the pouch of skin that holds them outside the body cavity, and the reason for that unusual arrangement is temperature: sperm production needs a temperature a couple of degrees below the body's core, which the abdomen cannot provide. The prostate is one of the accessory glands, sitting below the bladder and around the urethra, adding secretions that nourish the sperm and give semen its fluid volume — the same position that makes an enlarged prostate obstruct urine flow in older men.

• (a)Prostate gland — The prostate is a male accessory gland, lying just below the bladder and encircling the urethra. Its secretions form part of the seminal fluid, and its position around the urethra is why its enlargement in later life interferes with urination.
• (b)Testis — The testes are the male gonads. They produce sperm and secrete testosterone, the hormone responsible for the male secondary sexual characters, and are the exact counterpart of the ovaries in the female.
• (d)Scrotum — The scrotum is the sac of skin outside the abdomen that holds the testes. It exists to keep them at a temperature slightly lower than the rest of the body, which sperm formation requires.

The male reproductive system consists of the testes, held in the scrotum, where sperm and testosterone are made; a duct system of epididymis, vas deferens and urethra along which sperm travel; and accessory glands — the seminal vesicles, the prostate and the bulbourethral glands — whose secretions make up most of the volume of semen. The female system consists of the ovaries, the fallopian tubes, the uterus with its lower neck, the cervix, and the vagina. A few structures pair off neatly between the two: testes with ovaries as the gonads, and the scrotum with the labia as the corresponding external tissue.

Odd-one-out questions on anatomy are easiest if you build the systems as lists rather than trying to judge each name in isolation. Say the male list to yourself — testes, scrotum, epididymis, vas deferens, seminal vesicles, prostate, urethra, penis — and the intruder announces itself. The cervix is a good choice of intruder for an examiner because the word is familiar from public health messaging without its location always being clear; keeping the phrase 'neck of the uterus' attached to it removes the doubt permanently. Note that the urethra is common ground: in the male it carries both urine and semen, in the female only urine, so it appears in discussions of both systems without being an intruder in either.

• The cervix is the narrow lower part of the uterus, opening into the vagina, and is a female reproductive organ.
• The male reproductive system comprises the testes, scrotum, epididymis, vas deferens, seminal vesicles, prostate gland, bulbourethral glands, urethra and penis.
• The testes are the male gonads, producing both sperm and testosterone.
• The scrotum holds the testes outside the abdomen because sperm formation requires a temperature below the body's core temperature.
• The prostate lies below the bladder and surrounds the urethra, which is why its enlargement in older men obstructs the flow of urine.

• Recognising the cervix as a medical term without placing it, and so ruling out one of the male organs instead.
• Assuming a gland named in a male context must be male; the question rewards knowing where each organ sits, not what it sounds like.
• Forgetting that the urethra is shared between systems in the male, carrying both urine and semen.

Usually as an odd-one-out like this one, in either direction, or as a match between an organ and its function, or as a question on why the testes lie outside the abdomen.

• practice — not a real PYQ

  The cervix is a part of which one of the following organs?

  • (a)Urinary bladder
  • (b)Uterus
  • (c)Ovary
  • (d)Kidney

  Answer(b) Uterus — the cervix is the narrow lower portion, or neck, of the uterus, opening into the vagina.

• practice — not a real PYQ

  In human beings the testes lie in the scrotum, outside the abdominal cavity, because

  • (a)the abdomen has no space for them
  • (b)sperm formation requires a temperature lower than the body's core temperature
  • (c)they need direct contact with air
  • (d)hormone secretion is impossible inside the body

  Answer(b) sperm formation requires a temperature lower than the body's core temperature — the scrotum keeps the testes a little cooler than the rest of the body.