Human Reproduction
Dive into the complexities of the male and female human reproductive systems. Learn about the biological processes of gametogenesis, the menstrual cycle, fertilization, pregnancy, and embryonic development.
1. Choose the incorrect statement from the following:
a. In birds and mammals internal fertilisation takes place
b. Colostrum contains antibodies and nutrients
c. Polyspermy in mammals is prevented by the chemical changes in the egg surface
d. In the human female implantation occurs almost seven days after fertilisation
Answer
Answer: c
Explanation: Polyspermy in mammals is prevented by structural modifications to the zona pellucida (zona reaction), rather than chemical changes on the egg surface itself. Cortical granules release enzymes that harden this layer to physically block additional sperm penetration.
2. Identify the correct statement from the following:
a. High levels of estrogen triggers the ovulatory surge.
b. Oogonial cells start to proliferate and give rise to functional ova in regular cycles from puberty onwards.
c. Sperms released from seminiferous tubules are highly motile.
d. Progesterone level is high during the post ovulatory phase of menstrual cycle.
Answer
Answer: d
Explanation: During the post-ovulatory (luteal) phase, the corpus luteum actively secretes high levels of progesterone to maintain the uterine endometrium for potential implantation. The other statements are incorrect because estrogen does not directly trigger ovulation (LH does), oogonia stop dividing before birth, and newly released sperms in the testes are non-motile.
3. Spot the odd one out from the following structures with reference to the male reproductive system:
a. Rete testis
b. Epididymis
c. Vasa efferentia
d. Isthmus
Answer
Answer: d
Explanation: The isthmus is a structural segment of the female reproductive system, forming the narrow part of the fallopian tube that joins the uterus. The rete testis, epididymis, and vasa efferentia are all accessory transport ducts within the male reproductive system.
4. Seminal plasma, the fluid part of semen, is contributed by.
i. Seminal vesicle ii. Prostate gland iii. Urethra iv. Bulbourethral gland
(a) i and ii
(b) i, ii and iv
(c) ii, iii and iv
(d) i and iv
Answer
Answer: b
Explanation: Seminal plasma is the collective fluid secretion produced by the male accessory glands, which explicitly include the paired seminal vesicles, the prostate gland, and the paired bulbourethral glands. The urethra serves solely as a common passageway for both urine and semen, not as a secretory gland.
5. Spermiation is the process of the release of sperms from:
a. Seminiferous tubules
b. Vas deferens
c. Epididymis
d. Prostate gland
Answer
Answer: a
Explanation: Spermiation is the final stage of spermatogenesis where mature spermatozoa detach from the supporting Sertoli cells. They are then released directly into the central lumen of the seminiferous tubules.
6. Mature Graafian follicle is generally present in the ovary of a healthy human female around:
a. 5-8 day of menstrual cycle
b. 11-17 day of menstrual cycle
c. 18-23 day of menstrual cycle
d. 24-28 day of menstrual cycle
Answer
Answer: b
Explanation: A mature Graafian follicle typically finishes its development right before ovulation occurs in the middle of a standard 28-day cycle. Therefore, it is prominent and fully formed between the 11th and 17th days of the menstrual cycle.
7. Acrosomal reaction of the sperm occurs due to:
a. Its contact with zona pellucida of the ova
b. Reactions within the uterine environment of the female
c. Reactions within the epididymal environment of the male
d. Androgens produced in the uterus
Answer
Answer: a
Explanation: The acrosomal reaction is specifically triggered when the sperm head makes physical contact with the zona pellucida layer of the ovum. This contact causes the acrosome to release hydrolytic enzymes that digest a path for the sperm to enter the egg.
8. Which one of the following is not a male accessory gland?
a. Seminal vesicle
b. Ampulla
c. Prostate
d. Bulbourethral gland
Answer
Answer: b
Explanation: An ampulla is merely an anatomical term for an enlarged, widened portion of a tubular structure, such as the ductus deferens or fallopian tube, rather than an independent gland. The seminal vesicles, prostate, and bulbourethral glands are the true male accessory secretory glands.
9. The spermatogonia undergo division to produce sperms by the process of spermatogenesis. Choose the correct one with reference to above.
a. Spermatogonia have 46 chromosomes and always undergo meiotic cell division
b. Primary spermatocytes divide by mitotic cell division
c. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division
d. Spermatozoa are transformed into spermatids
Answer
Answer: c
Explanation: Secondary spermatocytes are haploid cells generated after the first meiotic division, meaning they contain exactly 23 chromosomes. They then complete the second meiotic division to produce four haploid spermatids.
10. Match between the following representing parts of the sperm and their functions and choose the correct option.
Column I | Column II |
A. Head | i. Enzymes |
B. Middle piece | ii. Sperm motility |
C. Acrosome | iii. Energy |
D. Tail | iv. Genetic material |
options:
a. A-ii, B-iv, C-i, D-iii
b. A-iv, B-iii, C-i, D-ii
c. A-iv, B- , C-ii, D-iii
d. A-ii. B-i, C-iii. D-iv
Answer
Answer: b
Explanation: The sperm head carries the nucleus with the genetic material (A-iv), while the middle piece contains mitochondria to generate energy (B-iii). The acrosome holds hydrolytic enzymes (C-i), and the flagellar tail is strictly responsible for sperm motility (D-ii).
11. Which among the following has 23 chromosomes?
a. Spermatogonia
b. Zygote
c. Secondary oöcyte
d. Oögonia
Answer
Answer: c
Explanation: A secondary oocyte is produced after the completion of Meiosis I, making it a haploid cell with exactly 23 chromosomes. In contrast, spermatogonia, oogonia, and zygotes are all diploid cells containing 46 chromosomes.
12. Match the following and choose the correct options:
Column I | Column II |
A. Trophoblast | i. Embedding of blastocyst in the endometrium |
B. Cleavage | ii. Group of cells that would differentiate as embryo |
C. Inner cell mass | iii. Outer layer of blastocyst attached to the endometrium |
D. Implantation | iv. Mitotic division of zygote |
Options:
a. A-ii, B-i, C-iii, D-iv
b. A-iii, B-iv, C-ii, D-i
c. A-iii, B-i, C-ii, D-iv
d. A-ii, B-iv, C-iii, D-i
Answer
Answer: b
Explanation: The trophoblast is the outer cellular layer that attaches to the endometrium (A-iii), and cleavage refers directly to the rapid mitotic divisions of the zygote (B-iv). The inner cell mass is the cluster that ultimately forms the embryo proper (C-ii), while implantation is the embedding process itself (D-i).
13. Which of the following hormones is not secreted by human placenta?
a. hCG
b. Estrogens
c. Progesterone
d. LH
Answer
Answer: d
Explanation: The human placenta acts as an endocrine tissue producing hormones like hCG, hPL, estrogens, and progesterone to support pregnancy. Luteinizing Hormone (LH) is exclusively secreted by the anterior pituitary gland in the brain.
14. The vas deferens receives duct from the seminal vesicle and opens into urethra as:
a. Epididymis
b. Ejaculatory duct
c. Efferent ductule
d. Ureter
Answer
Answer: b
Explanation: As the vas deferens enters the prostate region, it merges with the duct draining the seminal vesicle to form a single combined tube. This newly formed structure is called the ejaculatory duct, which then carries fluids into the urethra.
15. Urethral meatus refers to the:
a. Urinogenital duct
b. Opening of vas deferens into urethra
c. External opening of the urinogenital duct
d. Muscles surrounding the urinogenial duct
Answer
Answer: c
Explanation: The urethral meatus is the anatomical term for the external orifice at the tip of the penis or vulva. It serves as the functional external opening of the urinogenital duct through which bodily fluids exit.
16. Morula is a developmental stage:
a. Between the zygote and blastocyst
b. Between the blastocyst and gastrula
c. After the implantation
d. Between implantation and parturition
Answer
Answer: a
Explanation: The morula is a solid, mulberry-like ball of 8 to 16 cells (blastomeres) created by the initial cleavage divisions of the zygote. As it continues to divide and hollow out, it transforms into the blastocyst stage prior to implantation.
17. The membranous cover of the ovum at ovulation is:
a. Corona radiata
b. Zona radiata
c. Zona pellucida
d. Chorion
Answer
Answer: a
Explanation: Upon ovulation, the released secondary oocyte is immediately surrounded by an outer membranous, cellular envelope known as the corona radiata. This layer sits directly outside the non-cellular zona pellucida layer.
18. Identify the odd one from the following:
a. Labia minora
b. Fimbriae
c. Infundibulum
d. Isthmus
Answer
Answer: a
Explanation: The labia minora are fleshy folds of tissue that make up part of the female external genitalia (the vulva). In contrast, the fimbriae, infundibulum, and isthmus are interconnected internal anatomical segments comprising the fallopian tube.