Download Navodaya Vidyalaya Samiti – Bhopal Region.

Navodaya Vidyalaya Samiti – Bhopal Region.
CHAPTER- HUMAN REPRODUCTION
SALIENT POINTS


Reproductive events in human beings are: Gametogenesis, Insemination,
Implantation, Parturation, Fertilization. All these reproductive events occur
after puberty.
The male reproductive system: It is located in the pelvic region & consists of a
pair of testis, accessory ducts, glands & external genitals.
*
Testis: It is 4-5cm length,2-3cm width found in outside the abdominal cavity
within a pouch called scrotum. It helps in maintaining low temperature of the
testis(2-2.5degree centigrade lower than normal body temp) necessary for
spermatogenesis. Each testis has 250 testicular lobules. Each lobules contain 1-3
Semniferous tubule in which sperms are produced. Semniferous tubule is lined on
it’s inside by male germ cells- undergoes meiotic division for sperm formation &
sertoli cells- provide nutrition to dividing germ cells. Out side Semniferous tubule
called interstitial spaces, contain leydig cells- secrete androgens. Scrotum remains
connected with abdominal cavity by Injunial canals.
*
Accessory ducts: It includes rete testis, vas efferentia, epididymis, vas
deferens & ejaculatory duct. The seminiferous tubles are closed in one end but at
the other end they joint to a network of tubules called rete testis, which opens to vas
efferentia. Vas efferentia leave the testis & open into epididymis which leads to vas
deferens. Vas diferentia ascends to the abdomen & it receives a duct from seminal
vesicle & opens into urethra via ejaculatory duct. These ducts store & transport
sperms from testis to the out side through the penis to it’s external opening, urethral
meatus.
* Penis: it is the male external genital. It helps to facilitate insemination. The glans
penis remains covered by a loose fold of skin, foreskin.
* Male accessory glands: Secretion of these glands constitute the seminal plasma
which is rich in fructose, calcium & certain enzymes.
# Seminal vesicles: A pair of seminal vesicles join the vas differentia to form
ejaculatory duct. It secretes a viscous alkaline fluid rich in fructose.
# Prostrate gland: it is a single large gland thats surround the urethra. It secretes
an alkaline fluid that neutralizes the acidity of vagina during intercourse
# Bulbourethral gland: This gland secretes mucus containing fluid which helps
in the lubrication of the penis.
 The female reproductive system: the female reproductive system consists of a
pair of ovary, a pair of oviduct, uterus, cervix, vagina & external genital. A
pair of mammary gland is integrated structurally & functionally to support the
process of reproduction.
* Ovary: They are primary sex organ which produces female gamete & several
steroid hormones. These are located in the lower abdomen. It is 2-4cm length & is
connected to the pelvic wall & uterus by ligaments.
XII Class Biology – Resource Material
Page 7
Navodaya Vidyalaya Samiti – Bhopal Region.
* Oviduct: It is also called as fallopian tubes. It is 10-12cm long . The part of
oviduct closure to the ovary is funnel shaped, infundibulum. The edges of infundibulum
posses finger like projections, fimbriae which helps in collection of the ovum after
ovulation. Infundibulum opens to ampulla. The last part of oviduct, isthmus joins the
uterus. Fertilization of ovum always takes place in ampulla-isthmus junction.
* Uterus : It is also called as womb. The wall of uterus has three layers of tissue.
External layer- perimetrium, middle layer - myometrium & inner layer- endo
metrium. The uterus opens into vagina through a narrow cervix. The endometrium
undergoes cyclic changes during menstrual cycle.
* Female external genital: It includes mons pubis, labia majora, labia minora,
hymen & clitoris.
# Mons pubis- It is outer fatty tissue covered by skin & pubic hair
# Labia majora- These are fleshy folds of skin around vagina
# Labia minora- Small folds inner to labia majora.
# Hymen – It is partial opening to vagina.
#clitoris-It is a tiny finger like structure at upper end of labia minora.
* Mammary gland: A pair of breast containing mammary lobes & fat is
characteristic of all female mammals. Each breast contains 15-20 mammary lobes
containing clusters of cells, alveoli. The alveoli open into mammary tubules &
tubules of each mammary lobe to form mammary duct, mammary duct joint to form
mammary ampulla which further connects to lactiferous duct through which milk is
sucked out.
 Gametogenesis: The process of formation of gametes in the gonads (testis& ovary) is
called gametogenesis. It includes spermatogenesis(formation of sperms) &
oogenesis(formation of ova) in the testis & ovary respectively.
*Spermatogenesis- The process of sperm formation takes place in seminiferous
tubules of testis which is lined by germinal epithelial consisting immature male germ cells
spermatogonia. Spermatogonia (2n) undergoes mitosis & increase in number.Some
spermatogonia,called as primary spermatocyte undergoes meiosis to form secondary
spermatocyte(1n). The sec. spermatocyte undergo second meiotic division to produce four
equal, haploid spermatids which are transformed into spermatozoa by the process
spermiogenesis. Sperm heads become embedded in the sertoli cells. Sperms are released
by process of spermiation.
*Structure of sperm- Sperm is composed of a head, neck, middle piece and a tail. Sperm
is enclosed by plasma membrane. Sperm head contains an elongated haploid nucleus. Its tip
is called acrosome, which helps in fertilization of ovum by secreting enzymes. Middle
piece possess mitochondria and provides energy for tail movement so that sperm remain
motile. 200-300millions sperms are released during ejaculation. Seminal plasma along with
sperm form semen.
*Oogenesis:- It is the process of formation of a mature female gamete. It is initiated
during the embryonic development stage. Millions of gamete mother cells(oogonia) are
formed in each fetal ovary; no more oogonia are formed and added after birth. These cells
undergo meiotic division and get temporarily arrested at prophase-1, called as primary
oocytes, which is surrounded by a layer of granulose cells, called as primary follicles. At
puberty, only 60,000-80,000 primary follicles are left in each ovary. The primary follicles
XII Class Biology – Resource Material
Page 8
Navodaya Vidyalaya Samiti – Bhopal Region.
get surrounded by a new theca, called as secondary follicles, which is transferred into a
tertiary follicle by developing a fluid filled cavity antrum. It completes its 1st meiotic
division and produce a large haploid secondary oocyte and a tiny 1st polar body. The
tertiary follicle changes into graafian follicles. The secondary oocytes forms a membrane
of zona pellucida around it. The graafian follicles ruptured to release the secondary
oocyte(ovum) by the process called ovulation.
*menstrual cycle- It is a cyclic process of 28/29 days by which one ovum is released.
The 1st menstruation of a female begins at puberty is called a menarche. The phrases of
menstruation cycle are- menstruation, follicular phase, luteal phase. Secretion of
gonodotrophins increases gradually during follicular phase. LH and FSH attain a pick
level at the middle of the cycle. Rapid secretion of LH induces ovulation and is followed by
luteal phase in which corpus luteum is formed. Menstrual cycles ceases completely around
50 years of age called menopause.
Fertilization & Implantation: Fertilization is the process of fusion of a sperm with an
ovum, which takes place at ampulla-isthmus junction. Only one sperm can fertilize one
ovum because when sperms contacts zona pellucida of ovum, membrane undergoes
changes to avoid entry of another sperm. Enzymes secreted from acrosome help the sperm
enter into the cytoplasm of the ovum & initiates meiosis in ovum. Meiosis forms a second
polar body & haploid ovum. Fertilization of haploid nucleus of sperm with ovum forms
zygote. Sex of baby i.e. XX(female) XY(male) depends on sperm carrying either X or Y
haploid nuclei. So the sex of baby is determined by father. The mitotic division starts as
the zygote moves through the isthmus of the oviduct called cleavage towards the uterus &
form 2,4,8,16 daughter cells,blastomeres. The embryo with 8 to 16 blastomeres is called
morula.Morula divides & forms blastocysts which have outer layer of trophoblast &
inner layer of cell mass. Trophoblast layer gets attached to endometrium. Embedding of
blastocyst in endometrium of uterus is called implantation & it leads to pregnancy.
Pregnancy & Embryonic Development: After implantation ,trophoblast is surrounded
by finger like projections called chorionic villi. Placenta is then formed by interdigitation
of chorionic villi & uterine tissue. Placenta is connected to embryo through umbilical cord
which helps in transport of substances to & from the embryo. Placenta facilitate the supply
of oxygen & nutrient to the embryo,removal of carbon dioxide & excretory wastes
produced by the embryo. It also act as endocrine tissue & produces several hormones like
hCG,hPL,estrogens,progestogens & relaxin. Immediately after implantation, the inner
cell mass(embryo) differentiates into an outer layer, ectoderm & inner layer, endoderm. A
mesoderm soon appears between ectoderm & endoderm. The inner cell mass contains
certain cells called stem cell which have the potency to give rise to all the tissues & organs.
Average duration of human pregnancy lasts for nine months called as gestration period.
Parturition & lactation: Due to vigorous contraction of uterus at the end of pregnancy
causes expulsion of foetus.This process of child birth is called parturition. The signals for
parturition originate from the fully developed foetus & the placenta which induce mild
uterine contraction called foetal ejection reflex. Production of milk from milk glands at the
end of pregnancy is called lactation. Milk produced during initial few days of lactation is
called colostrum.
XII Class Biology – Resource Material
Page 9
Navodaya Vidyalaya Samiti – Bhopal Region.
VERY SHORT ANSWER TYPE QUESTIONS(1 MARK)
1. Where are the sperms produced in the testes?
Ans. Seminiferous tubules of testes.
2. Name the hormone secreted by leydig cells.
Ans. Testosterone.
3. Name the ducts that conduct the sperms out of the testes.
Ans. Vasa efferentia.
4. What is ejaculatory duct?
Ans. Seminal vesicle opens into vasa differentia forms ejaculatory duct that opens into
urethra.
5. Name the gland whose secretions help in the lubrication of the penis
Ans. Bulb urethral gland
6. What is birth canal?
Ans. Cervical canal & vagina form birth canal.
7. What is perimetrium?
Ans. External thin membranous layer of wall of uterus.
8. Write the technical term for the external opening of the urethra in a human male.
Ans. Urethral meatus.
9. What is gametogenesis?
Ans. Process of formation of male & female gametes in the gonads.
10.How many spermatozoa are produced from five secondary spermatocytes?
Ans. 10 spermatozoa.
11. What type of cell division occurs during formation of secondary spermatocytes
from primary spermatocytes?
Ans. Meiosis
12.Sperms have tail, where as eggs do not. Why
Ans. Eggs are non-motile & sperms have to travel up to egg.
13.Which part of the blastula is destinated to form germ layers of the developing
embryo in humans.
Ans. Inner Cell Mass
14.At what stage is the mammalian embryo implanted in the uterus?
Ans. Blastocyst stage
15.What is trophoectoderm?
Ans. Outer layer of blastocyst
16.What is the fate of trophoblast in mammalian embryo?
Ans. Placenta of fetus.
17. Where does fertilization take place in human female?
Ans. Ampulla-isthmus junction of oviduct
18. Define ovulation.
Ans. Process of rupture of a mature follicle & release of ovum from ovary.
XII Class Biology – Resource Material
Page 10
Navodaya Vidyalaya Samiti – Bhopal Region.
19. Define spermiogenesis?
Ans. Process of transfer of spermatid in to spermatozoa.
20. Define implantation.
Ans. Mammalian embryo become embedded to the endometrium of the uterus.
21. What is cleavage?
Ans. Rapid mitotic division of zygote.
22. What is insemination?
Ans. Process of deposition of sperm in the vagina.
23. What is the significance of LH surge?
Ans. Rupture graffian follicle & release of secondary oocyte.
24.What is corpus luteum?
Ans. Structure formed in mammalian ovary by transformation of a ruptured graffian
follicle.
25. When do the levels of FSH & LH reach the maximum in the menstrual cycle?
Ans. Middle of menstrual cycle(14 th. Day)
26.What is the first event that takes place when a sperm enters an ovum?
Ans. The second meiotic division of the secondary oocyte is completed.
27. Name the products/cells formed by meiosis II of secondary oocyte.
Ans. A large cell, ovum and a smaller cell, the second polar body.
28. What are blastomeres?
Ans. Cells formed by cleavage divisions of zygote
29. How many chromosomes are present in the nucleus of human sperm?
Ans. 23 chromosomes.
30. Which part of the sperm contains enzymes to digest egg envelops during
fertilization?
Ans. Acrosome
31. What is semen?
Ans. The seminal plasma along with sperm.
32. Why is the middle piece of a sperm called power house of sperm?
Ans. Due to mitochondria, it produce energy for sperm movement
33. What percentage of sperms in an ejaculation must have normal shape &size?
Ans.60% of the sperm
34. What is oogenesis?
Ans. Formation of mature female gamete
35. Name the fluid filled cavity in the tertiary follicle.
Ans. Antrum
36. When does the oocyte complete oogenesis?
Ans. When a sperm enters.
37. At what stage of life is oogenesis initiated in human female?
Ans. Embryonic developmental stage.
38. What is follicular atresia?
Ans. Degeneration of a number of primary follicles in the ovary from birth to puberty in a
human female.
XII Class Biology – Resource Material
Page 11
Navodaya Vidyalaya Samiti – Bhopal Region.
39. What is the advantage of the secondary oocyte retaining the bulk of nutrient rich
cytoplasm of the primary oocyte?
Ans. Nourish the embryo till implantation.
40.Name the membrane covering formed around the secondary oocyte.
Ans. Zona pellucida
41.What is meant by gestation period?
Ans. The time period between implantation and parturition.
42. What is placenta?
Ans. Structural & functional unit formed by the fetus & partly by the uterus
43. Define parturition.
Ans. The process of delivery of the fully developed fetus.
44. Name the two hormones that control parturition.
Ans. Relaxin & oxytocin
45. What is foetal ejection reflex?
Ans. Initial mild contractions of the uterus, initiated by the fully developed foetus & the
placental hormone.
46.What is lactation?
Ans. Process of feeding the new born baby with the milk secreted by the mammary
gland.
47.Define fertilization.
Ans. Fusion of male gamete with female gamete.
48. Name Primary female sex organs.
Ans. Ovaries
49. Which uterine layer undergoes changes during menstrual cycle?
Ans. Endometrium
50. What is hymen?
Ans. A partial membrane covering the Vaginal opening
51. During coitus, how many sperms are ejaculated?
Ans. 200 to 300 million sperms of which 60% of sperms have normal shape & 40% have
vigorous motility.
52. What is menarche?
Ans. First menstruation at puberty.
53. Which hormone maintain endometrium?
Ans. Progesterone
54. What is the initial symptoms of pregnancy?
Ans. All events of menstrual cycle stops, So no menstruation.
55. Why only one sperm can fertilize an ovum?
Ans. Because once a sperm fertilize it leads to change in membrane of ovum so that other
sperms are avoided.
56.When do zygote starts dividing ?
Ans. When mitotic divisions starts before the implantation of blastocyst into uterus.
57. Why hormone levels increase many folds during pregnancy?
Ans. To support foetal growth, metabolic changes in mother & maintain pregnancy.
58.Which cells of embryo have potency to give rise to all tissues & organs?
Ans.Stem cells of inner cell mass.
XII Class Biology – Resource Material
Page 12
Navodaya Vidyalaya Samiti – Bhopal Region.
SHORT ANSWER TYPE QUESTIONS(2 MARK)
1.Why are testis of human males considered extra-abdominal? What is the significance
of this condition?
Ans. Testis located outside in the scrotum. Scrotum provides 2-3 degree less temperature
than internal body temperature necessary for spermatogenesis.
2.Differenciate between vasa-differentia & vas-efferentia.
Ans. Any two diff.
3.What are primary sex organs? Name them in a human male & female respectively?
Ans.Organ which produce gametes & secrete sex hormones. Tetis in male & ovary in
female.
4. Where are laydeig cells present? What is their role in reproduction?
Ans. Interstitial space in testis. They secrete androgen mainly testosteron.
5.Name the two type of cells present in the inner lining of seminiferous tubules. What
are their functions?
Ans.Spermatogonia-produce male gamete
Sertoli cells- provide nutrition to the developing spermatozoans.
6.Differentiate between endometrium & myometrium.
Ans,Any two diff.
7.Write two major function, each of testis & ovary.
Ans. Testis-produces spermatozoa & secrete male sex hormone androgen.
Ovary-Produces female gamete & secretes female sex hormone estrogen &
progesterone.
8.What is seminal plasma? Mention it’s component.
Ans.Secretion of male reproductive glands like seminal vescicle , prostrate & cowpers
glands. It consist of fructose ,calcium & certain enzymes.
9.Where are fimbriae present in human female reproductive system? Give their
function.
Ans. Free edges of the infundibulum of the fallopian tube.They capture ova during
ovulation.
10.Differentiate between spermatogenesis & spermiogenesis.
Ans. Any two.
11.Name the hormones involved in the regulation of spermatogenesis .
Ans. GnRH ,FSH ,LH ,Testosteron like androgens.
12.Why is it considered that presence or absence of hymen is not an indicator of
virginity?
Ans. Hymen is the membrane that partially cover the vaginal opening which torn during
first coitus. But it can be torn by active participation in horse riding , cycling or by
sudden fall or jolt.
13.Describe different parts of fallopian tube of a human female .
Ans. It is 10-12cm long . Infundibulum,fimbriae,ampulla,isthmus.
14.Differentiate between spermatogenesis & oogenesis.
Ans Any two diff. .
15. Differentiate between primary Follicle& secondary follicle.
Ans. Any two diff.
XII Class Biology – Resource Material
Page 13
Navodaya Vidyalaya Samiti – Bhopal Region.
16. Differentiate between morula & blastocyst.
Ans . Ant two diff.
17. Differentiate between sec. follicle & tertiary follicle.
Ans. Any two diff.
18.What is placenta? Give it’s function .
Ans. Intimate connection between developing foetus & wall of uterus of mother. It
supplies oxygen & nutrients from maternal blood to the embryo & remove foetal waste
into maternal blood .it also secretes hormones like hCG, hPL, esterogen & progesterone.
19.What is corpus luteum? Under what conditions does it under go degeneration ?
Ans. After ovulation , Graffian follicle transform into corpus luteum . In absence of
fertilization it degenerates as the level of gonodotropin decreases.
20. Differentiate between tropoblast & inner cell mass?
Ans. Any two diff.
21.What is colostrums? How is milk production hormonally regulated?
Ans. First milk secreted from mammary glands just after parturition,which contains
antibody like IgA. Role of prolactin & oxytocin.
22.What is pregnancy hormone? Why is it so called? Name two sources of this
hormone in a human female.
Ans. hCG secreted by the placenta during pregnancy which stimulate & maintain the
corpus luteum to secret progesterone. Progesterone is necessary for continuation of the
pregnancy as it maintain endometrium of the uterus. Placenta & corpus luteum
23.Differentiate between the action of LH in males & females.
Ans. Any two difference.
24.The female vagina produces an acidic secretion.Why is a vaginal acidic
environment advantageous and by what mechanism do sperm survive it?
Ans. Acidic secretion in vagina is a barrier to disease producing organism. The male
prostate gland secrets an alkaline solution that neutralize the vaginal environment.
25.What are chorionic villi ? What is their fate?
Ans. Finger like projection of tropoblast produced after implantation. Form placenta.
26.Write function of the following(a)Acrosome,(b)Sper mtail
Ans.Acrosome-It contains enzyme which help in fertilization of ovum.
Sper mtail- Helps in sperm motility
27. Describe the structure of seminiferous tubule.
Ans. 250 testicular lobule.Each lobule contains 1 -3 highly coiled seminiferous tubule in
which sperms are produced. Each seminiferous tubule is lined by male germ cell &
sertoli cell.
28. Discuss the structure of uterine wall.
Ans. Outer- Perimetrium ,Middle – Myometrium, Inner – Endometrium. Wall of uterus
form part of placenta.
29. Write the function of epididymus.
Ans. Sperm undergoes maturation and acquire fertilizing capacity and increased motility.
Sperms are stored for a short period before entering the vas deferens.
30. Draw a labeled diagram of the sectional view of human ovum just after ovulation.
Ans. Label any four part.
XII Class Biology – Resource Material
Page 14
Navodaya Vidyalaya Samiti – Bhopal Region.
SHORT ANSWER TYPE QUESTIONS(3 MARK)
1. Describe the internal structure of human testes.
Ans. Refer text book.
2. Describe the accessory ducts of human male reproductive system.
Ans. Rete Testis, vasa efferentia, epididymis , vas deferens ,ejaculatory duct and urethra.
3. Name the cells found inside and outside the seminiferous tubule.Write the function
of each of them.
Ans. Inside- Spermatogonial cell- Spermatozoa
Sertoli cell- provide nutrition to germ cell and help in spermiogenesis.
Outside- Leydig cell- Secrete testosterone
4. Name the accessory glands of human male reproductive system and mention their
functions.
Ans. (i) A pair of seminal vesicles, (ii) A prostate gland (iii) Cowper’s gland
5. Describe the structure of mammary glands of a human female.
Ans. Refer text book
6. Draw a labeled diagram of the sectional view of mammary gland.
Ans. Label any six part
7. Name the pituitary hormones influencing leydig cell and sertoli cells present in
human testis. Explain the functions of these cells.
Ans. LH influences leydig cells- Secrets testosterone
FSH influence sertoli cells- provide nutrition to germ cell and help in
spermiogenesis.
8. Draw a labeled diagram of human sperm.
Ans. Label any six part
9. Draw a labeled diagram of a section through ovary.
Ans. Label any six part
10.In our society the women are often blame for giving birth to daughter. Can you
explain why this is not correct?
Ans. Males are heterogametic and produces two different types of sperms with X & Y
chromosome .Females are homogametic, produces only one type of egg with Xchromosome. If sperm with X chromosome fertilize the egg it develops into a female.If a
sperm with Y chromosome fertilize the egg it develops into a son.
11. Draw a labeled diagram of a cross - section through a small part of seminiferous
tubule of testis.
Ans. Label any six part.
12. What is menstrual cycle? Which hormones regulate menstrual cycle?
Ans. The cycle of events taking place in the reproductive organ in a primate female.
Hormones are GnRH ,FSH , LH, estrogen and progesterone.
13. Mention the target cells of LH in human males and females.Explain the effects and
the changes which the hormone induces in each case.
Ans. LH in male- Leydig cell- testosterone and it regulate spermatogenesis.
LH in female- Graffian follicle- it ruptures graffian follicle and release of ovum,
formation of corpus lueteum and secretion of progesterone.
XII Class Biology – Resource Material
Page 15
Navodaya Vidyalaya Samiti – Bhopal Region.
14. Explain the roles of ovarian hormones in inducing changes in the uterus during
menstrual cycle.What triggers release of oxytocin at the time of parturition.
Ans. Estrogen – Influences the uterus in follicular phase, regenerate endometrium
Progesterone – Endometrium becomes thickened and vascularised.
Foetal ejection reflex triggers release of oxytocin.
15. Enumerate the events that take place during fertilization in human beings.
Ans. Refer text book
16. Draw a labeled diagram showing a human foetus developing within the uterus.
Ans. Label any six part.
17. How many eggs are released by a human ovary in a month? How many eggs do
you think would have been released if the mother gave birth to identical twins? Would
your answer change if the twins born were fraternal?
Ans. One egg is released in a month. One egg ; the fertilized egg divides into two
separate cells each of which produces an individual. Two eggs.
18.Differentiate between sperm & ovum.
Ans. Any three difference
19.What is spermatogenesis? Explain.
Ans. Refer text book
20. What is the Significance of gametogenesis?
Ans.(i) Maintainance of chromosome number (ii) Variation (iii) Basic relation
LONG ANSWER TYPE QUESTIONS(5 MARK)
1. Explain phases of menstrual cycle in detailed.
Ans.Defination, Menstruation, Follicular phase, Luteal phase,Next cycle begin
2. Differentiate between spermatogenesis & oogenesis.
Ans. Any five major difference.
3. Draw a labeled diagram of the sectional view of human female pelvic showing
reproductive system. Describe it.
Ans. Lable any six parts. Explain important parts like ovary ,
oviduct,uterus,cervic&vagina
4.Describe the major steps in the dev. Of a fertilized egg up to complete differentiation
into blastocyst ready for implantation .
Ans.Refer text book.
5.Describe in proper sequence , the development of a foetus through various stages
during the gestation period.
Ans . refer text book.
6.What is oogenesis? Give a brief account on oogenesis.
Ans. Refer text book.
7. Drew a labelled diagram of human male reproductive system.Explain it.
Ans. Lable any six parts. Testis,vasa efferentia, epididymis, vasa differentia,ejaculatory
duct, urethra & accessory glands.
XII Class Biology – Resource Material
Page 16
Navodaya Vidyalaya Samiti – Bhopal Region.
8.Study the following chart . Name the hormone involved in each stage. Explain their
function.
Hypothalamus
pituitary
testis
sperms.
Ans. Refer text book.
9. Study the following chart . Name the hormone involved in each stage. Explain their
function.
Hypothalamus
pituitary
ovary
pregnancy.
Ans. Refer text book.
10.When & how does placenta develop in human female ? How is placenta connected
to the embryo? Placenta acts as an endocrine glands. Explain.
Ans. After implantation , chorionic villi develop on the tropoblast & the uterine tissue
form the placenta . placenta connected to embryo through umbilical cord. Placenta
secretes hCG, hPL , Esterogen & progesterone.
XII Class Biology – Resource Material
Page 17
Navodaya Vidyalaya Samiti – Bhopal Region.
CHAPTER- REPRODUCTIVE HEALTH
Reproductive health refers to healthy reproductive organs with normal functions.
According to WHO, reproductive health means a total well-being in all aspects of
reproduction,i.e., physical,emotional,behavioural & social.
Reproductive health – Problems & strategies: India was the first country to start
national level health programme in 1951. Government has started programme named
Reproductive & child health care(RCH). This prog. creates awareness by media about
reproduction related aspects, providing facilities & support for building reproductively
healthy society. Introduction of sex education in schools should be encouraged to give
right information to the young.
Adolescence age group should be made aware about myth and misconception about
sex related aspects , information about reproductive organs, safe and sexual hygienic
practices. STDs, birth control options care of pregnant mother, importance of breast
feeding to child, equal opportunity for male and female child.
Various action plan can be attended successfully with – (i)Infrastructural facilities
like tool and techniques (amniocentesis),(ii)Professional expertise- Care in problems like
pregnancy ,delivery ,STDs ,Abortion ,contraception’s (iii) Material support – Massive
child immunization. Amniocentesis is foetal sex determination test based on
chromosomal pattern in the amniotic fluid surrounding the developing embryo for any
abnormality. Saheli a new oral contraceptive for female was develop at Central Drug
Research Institute(CDRI) in Lucknow.
Population explosion and birth control – Population increase is due to decline in
Maternal Mortality Rate(MMR) and Infant Mortality Rate(IMR) ,increase no. of
people in reproducible age ,better medical facilities. Population growth should be
checked to avoid scarcity of basic requirements i.e., food, shelter and clothing. Strategies
to control population explosion are – Raising of marriageable age of female(18 years )
and male(21 years), awareness by slogan ‘Hum Do Hamara Do’, incentives for small
families , awareness about contraceptive methods. Contraceptive should be user friendly
,easily available, effective and reversible with no or least side effects. Contraceptive
should non-interfering in sexual act. Contraceptive method should be selected in
consultation with qualified medical professionals.
Contraceptives: Various types of contraceptives are :(i) Natural method – Periodic abstinence, coitus interrupts, Lactational amenorrhea.
(ii) Barrier – For male-condom & for female – diaphragm, cervical cap & vaults.
(iii) IUDs – Non-medicated, copper releasing & hormone releasing.
(iv) Oral contraceptive – Progestagens, Progestagens-estrogen combination & nonsteroidal preparation
(v) Implants or injection
(vi) Surgical methods –vasectomy & tubectomy.
Medical termination of pregnancy(MTP): Voluntary or intentional termination of
pregnancy before full term is called MTP or induced abortion.1/5 th. of pregnancy are
terminated in a year. Govt. of India legalized MTP in 1971 with some strict conditions to
avoid its misuse.
XII Class Biology – Resource Material
Page 18
Navodaya Vidyalaya Samiti – Bhopal Region.
Sexually transmitted disease(STDs): Diseases or infections which are transmitted
through sexual intercourse are called STDs or veneral diseases(VD) or reproductive
tract infection(RTI). HIV infection is most dangerous one. Except for hepatitis-B,
genital herpes & HIV infection, other STDs are completely curable if detected early &
treated properly. The incidence of STDs is especially high in age group of 15-24 years. It
can be prevented through (i) use of condom during coitus (ii) avoid sex with unknown
partners/multiple partners(iii) incase of doubt, go to a qualified doctor for early detection
& get complete treatment if diagnosed with disease.
Infertility: A large number of couples all over the world including India are infertile.
They are unable to produce child inspite of unprotected sexual co-habitation. The couples
could be assisted to have children through Assisted Reproductive Technologies(ART).
(i) In vitro fertilization(IVF): Fertilization out side the body in almost similar
conditions as that in the body followed by embryo transfer(ET). It is also known as test
tube baby prog. Ova from the wife/donor(female) & sperm from husband/donor(male) is
collected & is induced to form zygote under simulated condition.
(ii) Zygote intra fallopian transfer(ZIFT): The zygote or early embryos(up to 8
blastomeres) transferred into the fallopian tube.
(iii) Intra uterine transfer(IUT): Embryos with more than 8 blastomeres transferred
into uterus.
The fusion of gametes within the female to form zygote is called in-vivo fertilization.
(iv) Gamete intra fallopian transfer(GIFT): Transfer of an ovum collected from a
donor into the fallopian tube of another female who cannot produce one, but can provide
suitable environment for fertilization & further development.
(v) Intra Cytoplasmic Sperm Injection(ICSI): A sperm is directly injected into the
ovum to form an embryo in laboratory condition.
(vi) Artificial insemination(AI): Semen collected either from the husband or a
healthy donor is artificially introduce into the vagina. If , it is introduce into the uterus
of the female, called intra-uterine insemination(IUI).
XII Class Biology – Resource Material
Page 19
Navodaya Vidyalaya Samiti – Bhopal Region.
VERY SHORT ANSWER TYPE QUESTION(1MARK EACH)
1. What is ectopic pregnancy?
Ans. Implantation of a fertilized ovum out side of the uterine cavity.
2. Name the technique used for determining the sex & condition of the foetus.
Ans. Aminocentesis.
3. Write the fullform of MMR & ART.
Ans. Maternal mortality rate, Assisted reproductive technologies .
4. Name the surgical method of birth control in male & female .
Ans. Male- vasectomy, female – Tubectomy.
5. Name the common pills used by female.
Ans. Mala D, Saheli.
6. What does ICSI stand for ?
Ans. Intra cytoplasmic sperm injection.
7. What do you understand by reproductive health?
Ans. Healthy reproductive organs & their normal functioning.
8. When was family planning prog. Initiated in our country?
Ans. 1951.
9. Expand RCH prog.
Ans. Reproductive and child health care.
10. What is reproductive health according to WHO ?
Ans. A total well being in physical, emotional, behavioral & social aspects of
reproduction.
11. What is population explosion?
Ans. Enormous increase in the size of population in a short span of time.
12. Give one reason for a statutory ban on amniocentesis .
Ans. It is used to find out the sex of foetus & it leads to female foeticide.
13. Expand IVF & GIFT.
Ans. Invitro fertilization , Gamete intra fallopian transfer.
14.Expand MTP & STD.
Ans. Medical termination of pregnancy, Sexually transmitted disease.
15. Mention the principle of natural methods of birth control .
Ans. By avoiding the chance of ovum & sperms meeting.
16. What are the different ways in which progesterone or progesterone-esterogen
combination can be taken for contraception ?
Ans. Oral pills , injections & Implants .
17. What are the other names given to STDs ?
Ans. Venereal diseases, reproductive tract infections.
18. Mention the age group where STDs are reported to be very high in occurrence .
Ans. 15 to 24 years.
19. Name two STDs that can also be transmitted by sharing of injections needles of
surgical instruments.
Ans. Hepatitis-B & AIDS.
20. Name two viral STDs that are incurable .
XII Class Biology – Resource Material
Page 20
Navodaya Vidyalaya Samiti – Bhopal Region.
Ans. Hepatitis-B , AIDS & genital herpes.
21. Define infertility.
Ans. Inability of couple to produce children inspite of unprotected sexual combination.
22. What are ART?
Ans. The special techniques to help the infertile couples produce children.
23. Mention any two probable reason for rapid rise of population in our country.
Ans. Decline in death rate , decline in MMR, decline in IMR.
24. Expand IMR & IUDs.
Ans. Infant mortality rate , Intra uterine devices.
25. Name two important measures taken by the govt. to tackle the problem of
population explosion.
Ans. Raising of marriageable age of female to 18 years & male to 21years, incentives
given to couples for small families.
26. What are family planning prog.
Ans. To attain total reproductive health as social goal at national level.
27. What are the major tasks carried out in RCH?
Ans. Creating awareness about reproductive related aspects .
28. Name few reproductive related problems?
Ans. STDs, Abortions, Menstrual problem, Infertility.
29. What is amniocentesis?
Ans. A foetal sex determination test based on chromosomal pattern in amniotic fluid
surrounding the developing embryo.
30. Where was Saheli developed ?
Ans. CDRI in Lucknow.
31. Expand CDRI.
Ans. Central drug research institute.
32. Define periodic abstinence.
Ans. A natural method of abstinence from coitus from 10th to 17th day of menstrual cycle.
33. Which time period is said to be fertile in human female?
Ans. 10th to 17th day of the menstrual cycle.
34. What is coitus interrupts?
Ans. It is a withdrawal method in which male partner withdraws his penis from vagina
just before ejaculation.
35. Name some barriers of contraception’s used in females .
Ans. Diaphragm , cervical caps & vaults.
36. Give some examples of IUD’s.
Ans. Lippes loop, CuT, Cu 7, multiload 375
37. What are oral contraceptives?
Ans. Small doses of progesterone or progesterone-estrogen combination used by females
for oral administration.
38. What are pelvic inflammatory diseases?
Ans. Effect of untreated & complicated STDs .
XII Class Biology – Resource Material
Page 21
Navodaya Vidyalaya Samiti – Bhopal Region.
SHORT ANSWER TYPE QUESTION(2 MARKS EACH)
1.What is an ideal contraceptive?
Ans. Users friendly, easily available, 100% effective, reversible, no or less side effect,
not interfering in sexual drive.
2. What are natural methods of contraception?
Ans. Avoiding chances of mating between ovum & sperm that is periodic abstinence,
ciotus interrupts, lactetional amenorrhea.
3. Differentiate between vasectomy & tubectomy?
Ans. Any two diff.
4. How does condom works?
Ans. On the basis of barrier method , rubber/latex sheath used to cover penis in male just
before coitus so that ejaculated semen would not enter into female reproductive tract.
5. How barrier method is made more efficient ?
Ans. With spermicidal creams , jellies & foams.
6. As long as mother lactates fully, chances of conception are almost nil. Justify.
Ans. In a lactating mother, Ovulation & menstrual cycle do not occur after parturition. It
is effective up to six months.
7. Describe STDs. Give some examples of STDs?
Ans. Diseases which are transmitted through sexual intercourse . AIDS, Syphilis,
Gonorrhea, Genital herpes.
8. What is census? Give India’s population according to 2001 census?
Ans. It is an official counting of population & preparing data about age groups, births,
deaths, sex ratio, education etc. More than 1 billion .
9. Give any four possible ill effects of contraceptives.
Ans. Nausea , Abdominal pain , Breast cancer, Irregular menstrual bleeding.
10. What are the reasons for population explosion?
Ans. Write any two points.
11. Describe the technique by which genetic disorder in a developing foetus can be
detected.
Ans. Explain amniocentesis process.
12. Why there is utmost need of awareness about reproductive health in society?
Ans. Uncontrolled population growth, Social evils like sex abuses & to avoid sex related
crimes.
13. What measures govt. has taken to check the population growth rate?
Ans. Contraceptive methods, Raising of marriageable age of female to 18 years & males
to 21 years, Incentives to couples with small families, advertisement in media like “Ham
do Hamara do”.
14. Age group of 15-24 years is highly vulnerable to sexually transmitted diseases.
What preventive measures to be taken?
Ans. Avoiding sex with unknown partners, Using condoms during coitus, In case of
doubt go to a qualified doctor for early detection & cure.
XII Class Biology – Resource Material
Page 22
Navodaya Vidyalaya Samiti – Bhopal Region.
15. Explain any two method of ART that has helped childless couples to bear child .
Ans. Explain GIFT & ICSI. ( or any two)
16. Give reasons why family planning techniques are not adopted by all in our country.
Ans. People are not fully aware of the method, fear for some ill effects, Emotional &
social factors, Religious beliefs.
17.How do pills act as contraceptives in female?
Ans. Pills contain progestogens or Progestogen-estrogen combinations.
Inhibit ovulation & implantation, Alter the quality of cervical mucus and retard the
entry of sperms into cervix.
18. How do surgical procedures prevent conception in humans. Mention the way it is
achieved in human males.
Ans. Surgical procedures block the transport of gametes & achieve contraception.
Explain vasectomy in male.
19. Expand IUD. Why is hormone releasing IUD considered a good contraceptive to
space children?
Ans. Intra Uterine Device. It make the uterus unsuitable for implantation make the cervic
hostile to sperms, Increase the phagocytosis of sperms within the uterus.
20. How does CuT act as an effective contraceptive for human females?
Ans. CuT is an IUD. The copper ion releasing Suppress sperm mobility & the fertilizing
capacity of sperms, it increases phogocytosis of sperms within the uterus.
21. Is the use of contraceptive justified. Give reasons.
Ans. It is justified. There will be increase in the STDs. The population growth rate
increases.
22. Amniocentesis for sex determination is banned in our society . Is this ban
necessary?
Ans. As it is misused for female foeticide it is necessary but by banning this the
advantage of finding out chromosomal disorders of the foetus is lost. So it should be
legalized with some strict condition to avoid it’s misuse.
23. Is sex education is necessary in school. Why?
Ans. It is necessary. It avoids myths & misconceptions about sex related aspects, about
reproductive organs & adolescences related changes, about sex & hygienic sexual
practices, About STDs.
24. What are test tube babies?
Ans. The fusion of sperm & ovum is formed outside the women’s body to form a zygote
in the laboratory. The embryo is then implanted in uterus where it develops into a foetus.
25. What is infertility? Why it is an important aspects of reproductive health?
Ans. Un ability to produce children in spite of unprotected sexual co habition. Large
number the peoples all over the world are infertile due to physical, cogenial diseases or
immunological or physiological reasons
XII Class Biology – Resource Material
Page 23
Navodaya Vidyalaya Samiti – Bhopal Region.
SHORT ANSWER TYPE QUESTION(3 MARKS EACH)
1. What are the three types of IUDs available currently? Give examples of each.
Ans. (i) Non medicated IUDS- Lippes loop
(ii)Copper releasing IUDS- CuT, Cu7
(iii) Hormone releasing IUDS-LNG-20.
2. How do IUDS prevent pregnancy?
Ans. (i) Increase phagocytosis of sperms within the uterus
(ii) The copper ions released by IUDs suppress the sperm motility & their fertilizing
capacity
(iii) The hormone releasing IUDs make the uterus unstable for implantation & cervic
hostile to the sperms.
3. Draw diagrammatically the sterilization method, Vasectomy in a male.
Ans. Draw & label any four part.
4. Mention any six reproduction related problems.
Ans. Pregnancy, STD, Menstrual problems, Contraceptive methods, Infertility, Abortion,
Parturition.
5. Draw diagrammatically the sterilization method , Tubectomy in female.
Ans. Draw & label any four parts.
6. What is the advantage of saheli? Who prepared saheli?
Ans. A new oral contraceptive for female which contains a non steroidal preparations. It
is once a week pill with very side effects & high contraceptive value. It was developed by
CDRI in Lucknow.
8. Mention the common symptoms of curable STDs . Why do the infected persons not
ready to consult a doctor?
Ans. Itching,Fluid discharge, Swelling & slight pain. Social stigma attached to STDs,
absence or less significant symptoms in the early stages of infections.
9. Describe the three manner in which fertilization of human ovum by a sperm can be
prevented.
Ans. Explain in detail about Condom, IUDs, Diaphragms/cervical cap/vaults
10. Describe the technique by which genetic disorders in a developing foetus can be
detected .
Ans. Explain in detail amniocentesis process.
11. Why treatment & detection of STDs is usually delayed?
Ans. Early stages of infection shows less significant symptoms, Many a time infected
females are asymptomatic, Social stigma is attached to STD detection.
12. How does hepatitis-B & AIDS are transmitted?
Ans. Explain any three cause:
(i) Transfusion of blood (ii) Through sexual contact (iii) From infected mother to
foetus (iv) By shearing injection needles.
LONG ANSWER TYPE QUESTION(5 MARKS EACH)
1. Suggest some methods to assists infertile couples to have children.
Ans. Explain in detail(i)IVF (ii)ET (iii)GIFT (iv)ICSI (v)IUI
2. What steps can be taken for creating awareness among people about reproduction
related aspects?
Ans. Refer text book.
XII Class Biology – Resource Material
Page 24