Free Human Reproductive System MCQs with Answers

11. The fluid filled membrane that cushions the developing fetus and protects it from mechanical shock is the

• A. chorion
• B. allantois
• C. amnion
• D. yolk sac

Explanation: The amnion encloses the amniotic fluid in which the fetus floats, spreading any pressure evenly, keeping the temperature steady and allowing free movement of the limbs. The chorion is the outer membrane that contributes the fetal part of the placenta, so it has a nutritive rather than a protective role. In humans the yolk sac and allantois are much reduced compared with birds and reptiles.

12. The umbilical vein carries

• A. deoxygenated blood from the fetus to the placenta
• B. oxygenated blood from the placenta to the fetus
• C. fetal urine to the placenta for disposal
• D. maternal blood directly into the fetal circulation

Explanation: The cord contains two arteries and one vein, and as always the vein is named for the direction of flow towards the heart, so it brings oxygen and nutrients from the placenta to the fetus. The umbilical arteries do the reverse, carrying deoxygenated blood loaded with waste to the placenta. Maternal and fetal blood remain in separate vessels throughout, exchanging only by diffusion across the placental barrier.

13. The female gonads that produce ova and secrete the hormones oestrogen and progesterone are the

• A. ovaries
• B. uterus
• C. oviducts
• D. vagina

Explanation: The ovaries are both the source of egg cells and an endocrine gland, releasing the hormones that control the menstrual cycle and pregnancy. The uterus receives the embryo and the oviduct is the site of fertilisation, but neither produces gametes.

14. The inner lining of the uterus, which thickens each cycle and is shed during menstruation, is the

• A. perimetrium
• B. endometrium
• C. myometrium
• D. cervix

Explanation: The endometrium is the hormonally responsive layer where the embryo implants. The myometrium is the muscular wall that contracts in labour and the perimetrium the outer covering, so only the endometrium is shed in menstruation.

15. After their production, spermatozoa mature and are temporarily stored in the

• A. seminal vesicles
• B. prostate gland
• C. epididymis
• D. urethra

Explanation: Sperm leaving the seminiferous tubules are not yet motile; they gain the ability to swim while passing through the coiled epididymis where they are stored. The seminal vesicles and prostate only add fluid at the moment of ejaculation.

16. The secretion of the seminal vesicles is rich in a sugar that serves as fuel for sperm. This sugar is

• A. glucose
• B. sucrose
• C. lactose
• D. fructose

Explanation: Fructose provides the energy that powers the tail of the sperm during its journey. The prostate contributes a milky alkaline fluid instead, protecting sperm from the acidity of the vagina.

17. The testes hang in the scrotum outside the body cavity because

• A. sperm production needs a temperature slightly below body temperature
• B. the testes are too large to fit inside the abdomen
• C. testosterone breaks down at body temperature
• D. sperm must be released directly to the outside

Explanation: Spermatogenesis fails at the normal 37 degrees of the abdomen, so the scrotum keeps the testes about two degrees cooler. This is why undescended testes in childhood need correction to preserve fertility.

18. The umbilical cord of a human fetus normally contains

• A. one artery and one vein
• B. two arteries and one vein
• C. two arteries and two veins
• D. one artery and two veins

Explanation: Two umbilical arteries carry deoxygenated blood and wastes from fetus to placenta, while the single umbilical vein returns oxygenated blood and nutrients. Veins here carry waste and arteries carry it away, the reverse of the adult pattern, which catches many students.

19. After fertilisation, the zygote undergoes a series of rapid mitotic divisions without overall growth, called

• A. meiosis
• B. gastrulation
• C. cleavage
• D. implantation

Explanation: Cleavage divides the zygote into a ball of smaller cells as it travels down the oviduct, forming the morula and then the blastocyst. Meiosis makes gametes, and implantation happens later, once the blastocyst reaches the uterus.

20. Which of the following is NOT a part of the male reproductive system?

• A. Prostate gland
• B. Vas deferens
• C. Seminal vesicle
• D. Uterus

Explanation: The uterus belongs to the female system, where it nourishes the developing fetus. The prostate and seminal vesicles add fluids to semen, and the vas deferens transports sperm, so all three are male structures.