🌸 Chapter 2
Human Reproduction
(2 Marks )
1. What is the function of the
scrotum in males?
Answer:
The scrotum holds the testes outside the abdominal cavity, maintaining a
temperature about 2–2.5°C lower than body temperature, which is
essential for spermatogenesis.
2. Name the accessory glands of the
male reproductive system.
Answer:
The male accessory glands are the seminal vesicles, prostate gland,
and bulbourethral (Cowper’s) glands.
They secrete fluids that nourish and activate sperm.
3. What is semen?
Answer:
Semen is a mixture of spermatozoa and secretions of accessory glands. It
provides nutrients, medium, and enzymes for sperm transport and survival.
4. Differentiate between
spermatogenesis and spermiogenesis.
Answer:
- Spermatogenesis: Formation of haploid
spermatids from spermatogonia.
- Spermiogenesis: Transformation of spermatids
into mature, motile spermatozoa.
5. What is the role of Sertoli cells?
Answer:
Sertoli cells provide nourishment and structural support to developing
sperm and secrete inhibin, which regulates FSH secretion.
6. Name the hormones regulating
spermatogenesis.
Answer:
FSH and testosterone regulate spermatogenesis.
FSH acts on Sertoli cells, while LH stimulates Leydig cells to produce
testosterone.
7. What is the function of the
epididymis?
Answer:
The epididymis stores sperm temporarily and provides an environment for sperm
maturation and motility.
8. What is ovulation?
Answer:
Ovulation is the release of a mature ovum from the Graafian follicle in
the ovary, typically around the 14th day of the menstrual cycle.
9. Name the three layers of the
uterus.
Answer:
1.
Perimetrium – outer layer
2.
Myometrium – muscular middle layer
3.
Endometrium – inner glandular layer where
implantation occurs.
10. What is the function of fimbriae
in the fallopian tube?
Answer:
Fimbriae help collect the ovum released from the ovary and guide it into
the fallopian tube.
11. What is oogenesis?
Answer:
Oogenesis is the formation of mature ovum (egg) from oogonia in the
ovaries through mitotic and meiotic divisions.
12. How many sperms are produced
from one primary spermatocyte?
Answer:
One primary spermatocyte undergoes meiosis to produce four haploid
spermatozoa.
13. How many ova are released during
a woman’s lifetime?
Answer:
Only about 400–450 ova are released during a woman’s reproductive life,
from puberty to menopause.
14. What is the menstrual cycle?
Answer:
It is the cyclic changes in the female reproductive system occurring
every 28 days, involving menstruation, ovulation, and endometrial
regeneration.
15. Name the four phases of the
menstrual cycle.
Answer:
1.
Menstrual
phase
2.
Follicular
(Proliferative) phase
3.
Ovulatory
phase
4.
Luteal
(Secretory) phase
16. What causes menstruation to
occur?
Answer:
When fertilization doesn’t occur, progesterone and estrogen levels fall,
causing the endometrial lining to shed as menstrual flow.
17. What is the LH surge?
Answer:
A sudden increase in LH during mid-cycle (around day 14) triggers ovulation
and formation of the corpus luteum.
18. What is the corpus luteum?
Mention its function.
Answer:
The corpus luteum is formed from the ruptured follicle after ovulation.
It secretes progesterone to maintain the endometrium for
implantation.
19. What is fertilization?
Answer:
Fertilization is the fusion of haploid sperm and ovum nuclei to form a diploid
zygote in the ampullary–isthmic junction of the fallopian tube.
20. What is the zona pellucida?
Answer:
It is a glycoprotein layer surrounding the oocyte that helps in species-specific
sperm binding and prevents polyspermy.
21. Define implantation.
Answer:
Implantation is the attachment of the blastocyst to the endometrium,
usually on the 7th day after fertilization.
22. What is a morula?
Answer:
A morula is a solid ball of 8–16 blastomeres formed after
cleavage of the zygote before it develops into a blastocyst.
23. What is the function of the
placenta?
Answer:
Placenta facilitates nutrient, gas, and waste exchange between mother
and fetus and secretes hCG, hPL, estrogen, and progesterone.
24. What is the role of hCG hormone?
Answer:
Human Chorionic Gonadotropin maintains the corpus luteum during
early pregnancy and supports progesterone secretion.
25. What is colostrum?
Answer:
Colostrum is the first yellowish milk produced after childbirth, rich in
antibodies (especially IgA) that provide passive immunity to the
newborn.
26. What are the two important
hormones secreted by the placenta?
Answer:
1.
Human
Chorionic Gonadotropin (hCG)
2.
Human
Placental Lactogen (hPL)
Both support pregnancy and fetal development.
27. What is the gestation period in
humans?
Answer:
The gestation period is about nine months (280 days) — the time between
fertilization and childbirth.
28. What is parturition?
Answer:
Parturition is the process of childbirth, initiated by signals from
the fully developed fetus and oxytocin secretion.
29. What is lactation?
Answer:
Lactation is the secretion of milk from the mammary glands after
childbirth, regulated by prolactin and oxytocin.
30. What is amniotic fluid?
Answer:
A protective fluid surrounding the fetus inside the amniotic sac; it
cushions against shocks and prevents desiccation.
31. What is the function of oxytocin
in females?
Answer:
Oxytocin induces uterine contractions during childbirth and milk
ejection during lactation.
32. What prevents polyspermy in
humans?
Answer:
After one sperm enters, the zona pellucida hardens, preventing the entry
of additional sperm — a process called cortical reaction.
33. Name two natural barriers that
prevent sperm entry into the uterus.
Answer:
1.
Cervical
mucus plug
2.
Acidic
vaginal environment
34. What is the acrosome and what is
its function?
Answer:
The acrosome is a cap-like structure on the sperm head containing enzymes
(like hyaluronidase) that help penetrate the ovum.
35. What is capacitation?
Answer:
It is a functional maturation process that sperm undergo in the female
tract, enabling them to fertilize the ovum.
36. Name two male reproductive
disorders.
Answer:
1.
Cryptorchidism – failure of testes to descend
2.
Oligospermia – low sperm count
37. Name two female reproductive
disorders.
Answer:
1.
Amenorrhea – absence of menstruation
2.
Endometriosis – abnormal growth of endometrial
tissue outside uterus
38. What are the components of the
sperm tail?
Answer:
The tail is made of axoneme (microtubules) and mitochondria in
the midpiece, enabling sperm motility.
39. What is the role of
testosterone?
Answer:
Testosterone regulates male secondary sexual characters, spermatogenesis,
and accessory gland function.
40. What is the function of the
Graafian follicle?
Answer:
It nourishes the developing ovum and secretes estrogen before
rupturing during ovulation.
41. What is the role of estrogen in
the menstrual cycle?
Answer:
Estrogen promotes endometrial growth during the follicular phase
and helps in ovulation.
42. What is human placental lactogen
(hPL)?
Answer:
hPL helps in fetal growth and prepares mammary glands for
lactation.
43. What is the difference between
identical and fraternal twins?
Answer:
- Identical twins: From one zygote (monozygotic),
genetically identical.
- Fraternal twins: From two separate ova and
sperm (dizygotic), genetically different.
44. What is the significance of
progesterone?
Answer:
Progesterone maintains the endometrium, inhibits uterine contractions,
and supports pregnancy.
45. Name the stages of embryonic
development up to implantation.
Answer:
1.
Zygote
→ 2. Blastomeres → 3. Morula → 4. Blastocyst → 5. Implantation
46. What is the function of the
umbilical cord?
Answer:
It connects the embryo to the placenta and transports nutrients,
oxygen, and wastes between them.
47. What is the function of relaxin
hormone?
Answer:
Relaxin relaxes pelvic ligaments and cervix during late pregnancy to
facilitate childbirth.
48. Name any two sexually
transmitted diseases (STDs).
Answer:
1.
Syphilis
2.
AIDS
(Acquired Immunodeficiency Syndrome)
49. What are the permanent methods
of contraception?
Answer:
- Vasectomy (males): cutting vas deferens
- Tubectomy (females): cutting fallopian
tubes
50. What is infertility? Mention one
cause.
Answer:
Infertility is the inability to conceive after regular unprotected
intercourse.
Cause: Hormonal imbalance, blocked oviducts, or low sperm
count.
