NEET Biology: Reproduction · Chapter 2

Human Reproduction

What to remember

Spermatogenesis in the seminiferous tubules is driven by GnRH → LH and FSH. LH acts on Leydig cells (androgens). FSH acts on Sertoli cells (factors for spermiogenesis).
Oogenesis starts before birth. The primary oocyte is arrested in prophase I until puberty. Meiosis II of the secondary oocyte is completed only after a sperm enters.
The menstrual cycle is about 28 days. Ovulation occurs about day 14 after an LH surge. The corpus luteum secretes progesterone in the luteal phase.
Fertilisation occurs in the ampullary–isthmic junction of the oviduct. The zygote → morula → blastocyst; the trophoblast implants in the endometrium. Parturition is triggered by a foetal ejection reflex and oxytocin.

Male reproductive system

The male system lies in the pelvic region. It has a pair of testes, accessory ducts, accessory glands and the external genitalia (penis).

Testes. The testes lie outside the abdominal cavity in a pouch of skin called the scrotum. The scrotum keeps the testes about 2–2.5 °C below the normal body temperature, which is needed for spermatogenesis. Each testis is oval, about 4–5 cm long and 2–3 cm wide. It has about 250 compartments called testicular lobules. Each lobule contains one to three highly coiled seminiferous tubules, in which sperms are produced.

A seminiferous tubule is lined by two types of cells:

Cell	Location	Function
Spermatogonia (male germ cells)	Lining of tubule	Divide by mitosis; some become primary spermatocytes that undergo meiosis
Sertoli cells	Lining of tubule	Provide nutrition to germ cells; FSH acts on them
Leydig cells (interstitial cells)	In the spaces between tubules	Synthesise and secrete androgens (testosterone); LH acts on them

Accessory ducts. The seminiferous tubules open into the vasa efferentia through the rete testis. The vasa efferentia leave the testis and open into the epididymis. The epididymis leads to the vas deferens, which ascends to the abdomen, loops over the urinary bladder and receives a duct from the seminal vesicle. It then forms the ejaculatory duct, which opens into the urethra. The sequence is:

seminiferous tubules → rete testis → vasa efferentia → epididymis → vas deferens → ejaculatory duct → urethra → urethral meatus

The urethra starts from the urinary bladder and extends through the penis to its external opening, the urethral meatus.

Penis. The penis is the male external genitalia. The enlarged tip is the glans penis, covered by a loose fold of skin called the foreskin.

Accessory glands. These are the paired seminal vesicles, the prostate gland and the paired bulbourethral glands. Their secretions form the seminal plasma. It is rich in fructose, calcium and some enzymes. The bulbourethral gland secretion helps in lubrication of the penis.

Female reproductive system

The female system has a pair of ovaries, a pair of oviducts, a uterus, a cervix, a vagina and the external genitalia. Mammary glands are also considered part of it.

Ovaries. The ovaries are the primary female sex organs. They produce the ovum and steroid hormones (estrogen and progesterone). Each ovary is about 2–4 cm long and is connected to the pelvic wall and the uterus by ligaments. The ovary has a peripheral cortex and an inner medulla, and contains ovarian follicles at various stages.

Oviducts (fallopian tubes). Each oviduct is about 10–12 cm long. It extends from the ovary to the uterus.

Part	Position	Feature
Infundibulum	Funnel-shaped part near the ovary	Edges have finger-like fimbriae that collect the ovum after ovulation
Ampulla	Wider part after the infundibulum	Usual site of fertilisation (ampullary–isthmic junction)
Isthmus	Narrow part joining the uterus	Has a narrow lumen

Uterus. The uterus (womb) is single, inverted pear-shaped, and supported by ligaments. It opens into the vagina through the cervix. The cervical canal and the vagina form the birth canal. The uterine wall has three layers:

Layer	Position	Feature
Perimetrium	Outer	Thin membranous layer
Myometrium	Middle	Thick layer of smooth muscle; contracts strongly during delivery
Endometrium	Inner	Glandular lining; undergoes cyclical changes in the menstrual cycle

External genitalia (vulva). These include the mons pubis, labia majora, labia minora, hymen and clitoris. The mons pubis is a cushion of fatty tissue covered with hair. The labia majora are the fleshy folds. The labia minora lie inside them. The hymen often covers the vaginal opening partially, but its presence or absence is not a reliable sign of virginity. The clitoris is a tiny finger-like structure above the urethral opening.

Mammary glands. These are paired structures in the female. Each has 15–20 mammary lobes containing clusters of cells called alveoli. The alveoli secrete milk and open into mammary tubules. The tubules of a lobe join to form a mammary duct. Several ducts join to form a wider mammary ampulla, which is connected to a lactiferous duct through which milk is sucked out.

Gametogenesis

Spermatogenesis. It begins at puberty. The spermatogonia (2n = 46 chromosomes) in the seminiferous tubules multiply by mitosis. Some spermatogonia become primary spermatocytes, which undergo the first meiotic division to form two haploid secondary spermatocytes (n = 23). The second meiotic division gives four haploid spermatids. The sequence is:

spermatogonium (2n) → primary spermatocyte (2n) → secondary spermatocytes (n) → spermatids (n) → sperms (n)

The transformation of spermatids into sperms is called spermiogenesis. The release of sperms from the seminiferous tubules is called spermiation. Hormonal control: the hypothalamus secretes GnRH at puberty. GnRH acts on the anterior pituitary to release LH and FSH. LH acts on Leydig cells to produce androgens, which stimulate spermatogenesis. FSH acts on Sertoli cells, which secrete factors that help spermiogenesis.

Structure of a sperm. A sperm has a head, neck, middle piece and tail. The head has an elongated haploid nucleus capped by the acrosome, which holds enzymes that help the sperm to penetrate the ovum. The middle piece has many mitochondria, which give energy for the movement of the tail. The tail helps in swimming. Semen contains sperms and seminal plasma. About 200–300 million sperms are released in one ejaculation. For normal fertility, at least about 60 per cent should have normal shape and size, and at least about 40 per cent should show vigorous motility.

Oogenesis. The formation of the mature female gamete begins in the embryonic stage. Millions of oogonia form in each foetal ovary, and no new oogonia are formed after birth. The oogonia start meiosis I and are arrested at prophase I, now called primary oocytes. Each primary oocyte is surrounded by a layer of granulosa cells, forming a primary follicle. Many follicles degenerate between birth and puberty. At puberty only about 60,000–80,000 primary follicles remain in each ovary.

Stage	Features
Primary follicle	Primary oocyte surrounded by a single layer of granulosa cells
Secondary follicle	Surrounded by more layers of granulosa cells and a new theca
Tertiary follicle	Has a fluid-filled cavity (antrum); theca is organised into theca interna and theca externa
Graafian (mature) follicle	The primary oocyte completes meiosis I to form a large secondary oocyte and a tiny first polar body; zona pellucida surrounds the secondary oocyte

The Graafian follicle ruptures to release the secondary oocyte (ovum) in ovulation. The oocyte remains arrested at metaphase II until a sperm enters. Then meiosis II is completed to form the ovum and a second polar body. The remains of the follicle become the corpus luteum.

Menstrual cycle

The first menstruation at puberty is menarche. Cycles stop at about 50 years of age, called menopause. In a human female the cycle is about 28 days (it is not always 28 days). Ovulation usually occurs about day 14. Cycles are absent during pregnancy.

Phase	Approximate days	Events	Hormones
Menstrual	1–5	Breakdown of endometrium and bleeding, because no fertilisation occurred	Progesterone falls
Follicular (proliferative)	6–13	Primary follicles grow into Graafian follicle; endometrium regenerates	FSH rises; estrogen from growing follicles increases
Ovulatory	About 14	Graafian follicle ruptures and releases the ovum	LH and FSH surge (LH surge is the stronger trigger)
Luteal (secretory)	15–28	Ruptured follicle becomes corpus luteum; endometrium is maintained for implantation	Progesterone high from corpus luteum

If fertilisation does not occur, the corpus luteum degenerates and a new cycle begins. If fertilisation occurs, the corpus luteum persists and supports the pregnancy.

Fertilisation and implantation

During coitus, semen is deposited in the vagina (insemination). The sperms swim through the cervix and uterus into the oviduct. Only sperm and ovum that reach the ampullary–isthmic junction at the same time can fuse. A sperm contacts the zona pellucida of the ovum and induces changes in the membrane that block the entry of more sperms (preventing polyspermy). Acrosomal enzymes help the sperm to enter the cytoplasm of the ovum. This stimulates the completion of meiosis II. The haploid nuclei fuse to form a diploid zygote.

Cleavage. The zygote starts mitotic divisions (cleavage) as it moves through the isthmus toward the uterus, forming 2, 4, 8 and 16 daughter cells called blastomeres. The embryo with 8–16 blastomeres is a morula. The morula divides further and becomes a blastocyst. In the blastocyst, the blastomeres are arranged into an outer layer called the trophoblast and an inner group of cells attached to it, called the inner cell mass. The trophoblast layer gets attached to the endometrium, and the inner cell mass differentiates into the embryo. After attachment the uterine cells divide rapidly and cover the blastocyst. The blastocyst becomes embedded in the endometrium. This is implantation, and it leads to pregnancy.

zygote → cleavage → morula → blastocyst → implantation

Pregnancy and embryonic development

After implantation, finger-like projections called chorionic villi appear on the trophoblast. They are surrounded by uterine tissue and maternal blood. The chorionic villi and uterine tissue together form the placenta. It is connected to the embryo by the umbilical cord. The placenta supplies oxygen and nutrients, removes carbon dioxide and wastes, and acts as an endocrine tissue.

Placental hormone	Notes
hCG (human chorionic gonadotropin)	Maintains the corpus luteum early in pregnancy; produced only in pregnancy
hPL (human placental lactogen)	Produced only in pregnancy
Estrogens and progesterone	Maintain the endometrium and pregnancy; also produced by ovary
Relaxin	Produced by the ovary in the later phase of pregnancy

During pregnancy the levels of estrogens, progesterone, cortisol, prolactin and thyroxine are increased in the maternal blood. The hormones hCG, hPL and relaxin are produced only during pregnancy.

The inner cell mass contains stem cells. These are undifferentiated cells that can give rise to all tissues and organs. The inner cell mass differentiates into an outer layer called ectoderm and an inner layer called endoderm. A mesoderm soon appears between them. These three germ layers give rise to all tissues and organs.

Time	Development
End of 1 month	Heart is formed; heart sounds can be heard with a stethoscope
End of 2 months	Limbs and digits begin to develop
End of 12 weeks (first trimester)	Most major organ systems, limbs and external genital organs are well formed
5th month	First movements of the foetus; hair appears on the head
End of 24 weeks (second trimester)	Body is covered with fine hair; eyelids separate; eyelashes formed
End of 9 months	Foetus is fully developed and ready for delivery

Parturition and lactation

Parturition is the process of delivery of the foetus. It is induced by a complex neuroendocrine mechanism. Signals from the fully developed foetus and the placenta induce mild uterine contractions called the foetal ejection reflex. This triggers the release of oxytocin from the maternal pituitary. Oxytocin acts on the uterine muscle and causes stronger contractions. This in turn stimulates more oxytocin release. The cycle repeats and the contractions become strong enough to expel the baby. The placenta is also expelled after the baby is delivered.

The mammary glands start producing milk toward the end of pregnancy; this is lactation. The milk produced in the first few days is called colostrum. It contains several antibodies, especially IgA, which are essential for the development of resistance in the new-born. Breastfeeding is therefore recommended during the initial period.

NEET traps

1. Sertoli vs Leydig cells: Sertoli cells are inside the tubules and nourish germ cells (FSH). Leydig cells are outside the tubules and make androgens (LH).
2. Spermiogenesis vs spermiation: spermiogenesis is spermatid → sperm. Spermiation is the release of sperms into the lumen.
3. Meiosis I and II in the oocyte: meiosis I is completed before ovulation. Meiosis II is completed only after sperm entry.
4. Primary oocyte vs secondary oocyte: the primary oocyte is arrested at prophase I; the secondary oocyte at metaphase II.
5. LH vs FSH surge: both surge at mid-cycle, but the LH surge triggers ovulation.
6. Follicular phase vs luteal phase: estrogen dominates the follicular phase. Progesterone dominates the luteal phase.
7. Morula vs blastocyst: morula is a solid ball of 8–16 cells. Blastocyst has a trophoblast and an inner cell mass.
8. Trophoblast vs inner cell mass: trophoblast attaches to the endometrium. The inner cell mass becomes the embryo.
9. hCG, hPL, relaxin vs estrogen, progesterone: the first three are made only in pregnancy. Estrogen and progesterone are also made in the non-pregnant state.
10. Perimetrium vs myometrium vs endometrium: outer thin layer, middle muscle layer, inner glandular layer.

One-liners

1. Testes lie in the scrotum, about 2–2.5 °C below body temperature.
2. Each testis has about 250 lobules, and each lobule has one to three seminiferous tubules.
3. Spermatogonia have 46 chromosomes and sperms have 23.
4. GnRH acts on the anterior pituitary to release LH and FSH.
5. The acrosome holds enzymes; the middle piece holds mitochondria.
6. Seminal vesicles, prostate and bulbourethral glands are the accessory glands.
7. The oviduct has infundibulum, ampulla and isthmus in that order from the ovary.
8. The uterine layers from outside are perimetrium, myometrium and endometrium.
9. The mammary lobes number about 15–20 in each breast.
10. About 60,000–80,000 primary follicles remain in each ovary at puberty.
11. The Graafian follicle releases a secondary oocyte surrounded by the zona pellucida.
12. The corpus luteum secretes progesterone.
13. The cleavage divisions produce blastomeres, with no increase in overall size of the embryo.
14. The placenta is formed from chorionic villi and uterine tissue.
15. Colostrum has IgA antibodies and is produced in the first few days of lactation.

Practice questions

Which cells in the testis secrete androgens?
1. Sertoli cells
2. Leydig cells
3. Cells of the rete testis
4. Spermatogonia
Answer
B. Leydig cells
Leydig (interstitial) cells lie between the tubules and secrete androgens under LH.
The scrotum keeps the testes at a temperature about how much below normal body temperature?
1. 5–6 °C
2. 8–10 °C
3. 0.2–0.5 °C
4. 2–2.5 °C
Answer
D. 2–2.5 °C
This lower temperature is needed for spermatogenesis.
The usual site of fertilisation in the human female is the
1. body of the uterus
2. cervix
3. ampullary–isthmic junction of the oviduct
4. infundibulum
Answer
C. ampullary–isthmic junction of the oviduct
Sperm and ovum fuse at the ampullary–isthmic junction.
Which uterine layer undergoes cyclical changes during the menstrual cycle?
1. Endometrium
2. Perimetrium
3. Cervical wall
4. Myometrium
Answer
A. Endometrium
The glandular endometrium proliferates and is shed in the cycle.
The acrosome of a sperm contains
1. contractile filaments of the tail
2. the haploid nucleus
3. enzymes that help in penetrating the ovum
4. mitochondria for energy
Answer
C. enzymes that help in penetrating the ovum
The acrosome is a cap over the head holding enzymes; mitochondria are in the middle piece.
A human secondary spermatocyte contains how many chromosomes?
1. 23
2. 46
3. 92
4. 12
Answer
A. 23
Meiosis I halves the number from 46 to 23.
Ovulation is triggered mainly by a surge of
1. hCG
2. progesterone
3. prolactin
4. LH
Answer
D. LH
The mid-cycle LH surge ruptures the Graafian follicle.
A morula is an embryo of about
1. 2–4 blastomeres
2. 300 cells with a cavity
3. a single layer of trophoblast cells only
4. 8–16 blastomeres
Answer
D. 8–16 blastomeres
Cleavage gives a solid ball of 8–16 blastomeres called the morula.
Which hormone is produced in the body only during pregnancy?
1. Estrogen
2. Human placental lactogen
3. Progesterone
4. Follicle stimulating hormone
Answer
B. Human placental lactogen
hCG, hPL and relaxin are produced only in pregnancy.
The first menstruation at puberty is called
1. menarche
2. menopause
3. ovulation
4. parturition
Answer
A. menarche
Menarche is the onset; menopause is the end of cycles at about 50 years.
Colostrum is rich in
1. lactose only
2. IgE antibodies
3. IgA antibodies
4. relaxin
Answer
C. IgA antibodies
Colostrum has antibodies, especially IgA, for the new-born.
Finger-like fimbriae are located at the margin of the
1. ampulla
2. infundibulum
3. isthmus
4. cervix
Answer
B. infundibulum
Fimbriae of the infundibulum collect the ovum released at ovulation.
The vas deferens joins the duct of the seminal vesicle to form the
1. rete testis
2. ejaculatory duct
3. epididymis
4. vasa efferentia
Answer
B. ejaculatory duct
The ejaculatory duct then opens into the urethra.
In a mammary gland the mammary ampulla is connected to a
1. alveolus
2. mammary lobe
3. lactiferous duct
4. mammary tubule
Answer
C. lactiferous duct
Several mammary ducts form the ampulla, which opens into the lactiferous duct.
At puberty each ovary has approximately how many primary follicles?
1. 60,000–80,000
2. about 2 million
3. 600–800
4. 6–8 lakh
Answer
A. 60,000–80,000
Many follicles degenerate before puberty, leaving about 60,000–80,000.
The outer layer of cells of the blastocyst is the
1. morula
2. inner cell mass
3. zona pellucida
4. trophoblast
Answer
D. trophoblast
Trophoblast attaches to the endometrium; the inner cell mass forms the embryo.
Given below are two statements: Statement I: Sertoli cells provide nutrition to the germ cells. Statement II: FSH acts on the Leydig cells. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
C. Statement I is correct but Statement II is incorrect
FSH acts on Sertoli cells; LH acts on Leydig cells.
Given below are two statements: Statement I: Spermiogenesis is the release of sperms from the seminiferous tubules. Statement II: Spermiation is the transformation of spermatids into sperms. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
B. Both Statement I and Statement II are incorrect
The two terms are swapped: spermiogenesis is spermatid to sperm; spermiation is the release.
Given below are two statements: Statement I: Primary oocytes are arrested at prophase I of meiosis I. Statement II: Meiosis II of the secondary oocyte is completed only after a sperm enters. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
A. Both Statement I and Statement II are correct
Both statements describe the standard arrest points in oogenesis.
Given below are two statements: Statement I: The secondary oocyte is released at ovulation. Statement II: The first polar body is formed after fertilisation. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
C. Statement I is correct but Statement II is incorrect
The first polar body forms at the end of meiosis I, before ovulation; the second polar body forms after sperm entry.
Which of the following statements are correct? 1. The perimetrium is the thin outer membranous layer of the uterus. 2. The endometrium is the thick smooth muscle layer. 3. The myometrium contracts strongly during delivery.
1. 1 and 2 only
2. 2 and 3 only
3. 1 and 3 only
4. 1, 2 and 3
Answer
C. 1 and 3 only
Endometrium is the inner glandular layer; the muscular layer is myometrium.
Given below are two statements: Statement I: Progesterone is the dominant hormone of the luteal phase. Statement II: The corpus luteum develops from the ruptured Graafian follicle. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
A. Both Statement I and Statement II are correct
The corpus luteum forms after ovulation and secretes progesterone.
Given below are two statements: Statement I: Estrogen and progesterone are produced only during pregnancy. Statement II: Human placental lactogen is produced only during pregnancy. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
D. Statement I is incorrect but Statement II is correct
Estrogen and progesterone are also made by the ovary in non-pregnant women.
Given below are two statements: Statement I: The morula has a fluid-filled cavity and a trophoblast layer. Statement II: The blastocyst has an outer trophoblast and an inner cell mass. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
D. Statement I is incorrect but Statement II is correct
The morula is a solid ball; the blastocyst has the trophoblast and inner cell mass.
Given below are two statements: Statement I: Fertilisation in humans takes place in the uterus. Statement II: The zygote undergoes mitotic cleavage while moving toward the uterus. Choose the correct answer.
1. Both Statement I and Statement II are correct
2. Both Statement I and Statement II are incorrect
3. Statement I is correct but Statement II is incorrect
4. Statement I is incorrect but Statement II is correct
Answer
D. Statement I is incorrect but Statement II is correct
Fertilisation is in the ampullary-isthmic region of the oviduct.
Which of the following statements are correct? 1. The heart is formed by the end of the first month of pregnancy. 2. The first movement of the foetus is seen in the fifth month. 3. The eyelids separate by the end of the first trimester.
1. 1 and 2 only
2. 2 and 3 only
3. 1 and 3 only
4. 1, 2 and 3
Answer
A. 1 and 2 only
Eyelid separation and eyelashes appear by the end of 24 weeks (second trimester).
Assertion (A): The testes lie outside the abdominal cavity in the scrotum. Reason (R): Spermatogenesis needs a temperature lower than normal body temperature.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
A. Both A and R are true and R is the correct explanation of A
The scrotum keeps the testes about 2–2.5 °C cooler, which spermatogenesis needs.
Assertion (A): Colostrum is important for the new-born. Reason (R): The mammary glands begin to produce milk toward the end of pregnancy.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
B. Both A and R are true but R is not the correct explanation of A
Both are true, but the timing of milk production does not explain why colostrum is important (antibodies do).
Assertion (A): Fimbriae help to collect the ovum after ovulation. Reason (R): Fimbriae are located at the isthmus of the oviduct.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
C. A is true but R is false
Fimbriae are on the infundibulum, not the isthmus.
Assertion (A): Oogenesis begins at puberty. Reason (R): Primary oocytes are formed during embryonic life.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
D. A is false but R is true
Oogenesis starts in the foetal ovary; only follicle growth and ovulation begin at puberty.
Assertion (A): Normally only one sperm fertilises an ovum. Reason (R): Contact of a sperm with the zona pellucida changes the membrane and blocks the entry of other sperms.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
A. Both A and R are true and R is the correct explanation of A
This block prevents polyspermy.
Assertion (A): Oxytocin causes strong uterine contractions during labour. Reason (R): Oxytocin is released from the ovary.
1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true but R is not the correct explanation of A
3. A is true but R is false
4. A is false but R is true
Answer
C. A is true but R is false
Oxytocin is released from the maternal pituitary, so R is false.
Match List I with List II. List I: a. Sertoli cells b. Leydig cells c. Acrosome d. Middle piece List II: i. Androgen secretion ii. Nutrition of germ cells iii. Enzymes for penetration of ovum iv. Mitochondria for energy
1. a-i, b-ii, c-iii, d-iv
2. a-ii, b-i, c-iii, d-iv
3. a-ii, b-i, c-iv, d-iii
4. a-iii, b-iv, c-ii, d-i
Answer
B. a-ii, b-i, c-iii, d-iv
Sertoli-nutrition (ii), Leydig-androgens (i), acrosome-enzymes (iii), middle piece-mitochondria (iv).
Match List I with List II. List I: a. Infundibulum b. Ampulla c. Isthmus d. Fimbriae List II: i. Site of fertilisation ii. Narrow part joining the uterus iii. Funnel-shaped part near the ovary iv. Finger-like projections that collect the ovum
1. a-iv, b-i, c-ii, d-iii
2. a-iii, b-i, c-ii, d-iv
3. a-iii, b-ii, c-i, d-iv
4. a-i, b-iii, c-ii, d-iv
Answer
B. a-iii, b-i, c-ii, d-iv
Infundibulum-iii, ampulla-i, isthmus-ii, fimbriae-iv.
Match List I with List II. List I: a. Menstrual phase b. Follicular phase c. Ovulatory phase d. Luteal phase List II: i. Corpus luteum secretes progesterone ii. Release of the ovum iii. Breakdown of the endometrium iv. Growth of follicles with rising FSH
1. a-ii, b-iv, c-iii, d-i
2. a-iii, b-iv, c-ii, d-i
3. a-iii, b-ii, c-iv, d-i
4. a-iv, b-iii, c-ii, d-i
Answer
B. a-iii, b-iv, c-ii, d-i
Menstrual-iii, follicular-iv, ovulatory-ii, luteal-i.
Match List I with List II. List I: a. hCG b. Relaxin c. Oxytocin d. GnRH List II: i. Strong uterine contractions ii. Maintains the corpus luteum early in pregnancy iii. Acts on the pituitary to release LH and FSH iv. Produced by the ovary in the later phase of pregnancy
1. a-iv, b-ii, c-i, d-iii
2. a-ii, b-i, c-iv, d-iii
3. a-i, b-iv, c-ii, d-iii
4. a-ii, b-iv, c-i, d-iii
Answer
D. a-ii, b-iv, c-i, d-iii
hCG-ii, relaxin-iv, oxytocin-i, GnRH-iii.
Match List I with List II. List I: a. Morula b. Blastocyst c. Spermiation d. Spermiogenesis List II: i. Spermatid to sperm ii. Release of sperms into the lumen of the tubule iii. A ball of 8–16 blastomeres iv. Trophoblast with an inner cell mass
1. a-iii, b-iv, c-i, d-ii
2. a-iii, b-iv, c-ii, d-i
3. a-iv, b-iii, c-ii, d-i
4. a-ii, b-iv, c-iii, d-i
Answer
B. a-iii, b-iv, c-ii, d-i
Morula-iii, blastocyst-iv, spermiation-ii, spermiogenesis-i.
Match List I with List II. List I: a. Ectoderm b. Endoderm c. Mesoderm d. Trophoblast List II: i. Outer layer of the inner cell mass ii. Inner layer of the inner cell mass iii. Appears between the other two germ layers iv. Outer layer of the blastocyst that attaches to the endometrium
1. a-i, b-iii, c-ii, d-iv
2. a-ii, b-i, c-iii, d-iv
3. a-iv, b-ii, c-iii, d-i
4. a-i, b-ii, c-iii, d-iv
Answer
D. a-i, b-ii, c-iii, d-iv
Ectoderm-i, endoderm-ii, mesoderm-iii, trophoblast-iv.
In a woman with a regular 28-day cycle, ovulation is expected about on day
1. 1
2. 14
3. 7
4. 25
Answer
B. 14
Ovulation occurs about midway, after the LH surge.
A semen sample shows 70% sperms of normal shape and size but only 20% with vigorous motility. Compared with usual fertility figures, which parameter is below the usual level?
1. Shape and size (usually at least about 60%)
2. Motility (usually at least about 40%)
3. Both are below normal
4. Neither is below normal
Answer
B. Motility (usually at least about 40%)
The usual limit is about 60% normal form and 40% motile; 20% motility is low.
A tumour destroys all Leydig cells of an adult male. The most direct effect is
1. reduced androgen secretion
2. absence of seminal plasma
3. blockage of the vas deferens
4. failure of FSH secretion by the testis
Answer
A. reduced androgen secretion
Leydig cells secrete androgens; spermatogenesis is also reduced.
After ovulation the ruptured follicle fails to form a corpus luteum. Which change is most likely?
1. Ovulation occurs twice
2. The secondary oocyte remains in the follicle
3. The endometrium is not maintained because progesterone is low
4. FSH secretion becomes continuous
Answer
C. The endometrium is not maintained because progesterone is low
The corpus luteum secretes the progesterone that maintains the endometrium in the luteal phase.
Which event occurs only after a sperm enters a secondary oocyte?
1. Formation of the Graafian follicle
2. Release of the first polar body
3. Rupture of the follicle
4. Completion of meiosis II with release of the second polar body
Answer
D. Completion of meiosis II with release of the second polar body
The secondary oocyte is arrested at metaphase II until sperm entry.
A pregnancy test detects in the urine of a pregnant woman the hormone
1. hCG
2. Oxytocin
3. FSH
4. Prolactin
Answer
A. hCG
hCG is made by the trophoblast and placenta only in pregnancy.
A doctor hears the foetal heartbeat with a stethoscope for the first time. Approximately how old is the pregnancy?
1. About 5 months
2. About 12 weeks
3. About 1 month
4. About 9 months
Answer
C. About 1 month
The heart is formed by the end of the first month and its sound can then be heard.

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