REPRODUCTION IN ORGANISMS class 10 science

byGURUKUL with ARYA GAUTAM ,7903268149 -September 18, 2021

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REPRODUCTION IN ORGANISMS - I : MCQs & SHORT ANSWERS

MULTIPLE-CHOICE QUESTIONS

SELECT THE CORRECT ALTERNATIVE:

Which of the following is not a unicellular organism ?

Amoeba
Paramoecium
Hydra
Yeast

Which of the following shows budding ?

Yeast
Amoeba
Paramoecium
Plasmodium

Which of the following shows multiple fission ?

Hydra
Yeast
Spirogyra
Plasmodium

Which is the most common method of reproduction in majority of fungi and bacteria ?

Binary fission
Multiple fission
Budding
Spore formation

Which of the following shows spore formation ?

Amoeba
Mucor
Plasmodium
Paramoecium

Regeneration is observed in ______.

Amoeba
Planaria
Spirogyra
Yeast

Which of the following does not show regeneration ?

Mucor
Planaria
Sponges
Starfish

Which of the following is not an artificial method of vegetative propagation ?

Cutting
Layering
Grafting
Hybridization

Testes produce ______ hormone.

Estrogen
Testosterone
Progesterone
Both estrogen and testosterone

Which of the following is not produced in the ovary ?

Ovum
Estrogen
Progesterone
Testosterone

The main reproductive organ of human male is ______.

a pair of testes
vas deferens
urethra
penis

The main female reproductive organ is ______.

Fallopian tubes
uterus
vagina
a pair of ovaries

The first phase of the sexual cycle in human female is called ______.

ovulation
implantation
menstruation
follicle phase

Menstrual flow(menstruation) lasts for about ______ days.

2 - 3
3 - 5
5 - 7
14

In a normal healthy woman, menstruation occurs every ______ days.

14
28 - 32
21 - 24
270

What marks the beginning of the reproductive life of a woman ?

ovulation
menopause
menarche
fertilisation

What is formed after fertilisation ?

A sperm
An ovum
A zygote
A gamete

Where does fertilisation take place ?

vagina
cervix
Fallopian tube
uterus

What should be the normal weight of a fully matured foetus (child at birth)?

2.5 - 3.0 pounds
2.5 - 3.0 kg
3.0 - 3.5 pounds
3.0 - 3.5 kg

______ prevents ovulation.

Testosterone
Progesterone
Estrogen
Contraception

Which of the following shows budding ?

Hydra
Amoeba
Paramoecium
Spirogyra

Several new individuals are produced.

Binary fission
Multiple fission
Both binary fission and multiple fission
Fertilisation

In grafting the plant rooted in the soil is called ______.

stock
sucker
scion
rhizome

Which of the following plants shows vegetative propagation ?

Wheat
Radish
Sunflower
Bryophyllum

Testes in human male are located in ______.

abdominal cavity
vas deferens
scrotum
penis

In the process of sexual reproduction ______.

only males are needed
both male and female are needed
only females are needed
only mitosis is involved

The process of release of an egg from the ovary is called ______.

reproduction
ovulation
menstruation
fertilisation

______ takes place in a woman after 45 - 50 years.

Menstruation
Ovulation
Menopause
Lactation

The period taken for one complete menstrual cycle is ______.

31 days
32 - 35 days
28 - 32 days
22 - 25 days

The development of foetus inside the uterus till birth is called ______.

gestation
parturition
lactation
fertilization

The unicellular fungus which shows bud formation is ______.

mucor
yeast
amoeba
none of these

The animal which shows regeneration is ______.

amoeba
paramoecium
hydra
rhizopus

The method by which desired characters of two plants can be combined is ______.

cutting
layering
budding
grafting

The disease caused by treponema palidium is ______.

AIDS
syphillis
gonorrhoea
hepatitis

Yeast reproduces by...

budding
fission
regeneration
spore formation

A chain of buds is formed in...

hydra
yeast
mucor
plasmodium

Vegetative propagation is observed in...

yeast
hydra
mucor
bryophyllum

______ is useful where seeds have long dormancy period and poor germination capacity.

Cutting
Layering
Grafting
Regeneration

______ is a very useful method for developing garden.

Cutting
Layering
Grafting
Budding

The stage at which there is a gradual change in structure of reproductive organs in human male and female is called...

spermatogenesis
oogenesis
menarche
puberty

The temperature in the scrotum is about ______ deg C lower than the body temperature.

2
3
5
6

Which of the following is not a part of reproductive system in human male ?

Testis
Seminal vesicle
Clitoris
vas deferens

Which of the following is not a part of reproductive system in human female ?

Ovary
Cervix
Vagina
vas deferens

The sexual cycle in human female starts at...

birth
the age of 45
the age of 28
puberty stage

Ovulation occurs on the ______ day of the sexual cycle.

14th
20th
28th
any

The sexual cycle in human female remains active(functional), generally, up to the age of...

30 years
35-40 years
45-50 years
55-60 years

The 14th day of sexual cycle in human female is important because on that day...

ovulation occurs
she becomes pregnant
menstrual flow starts
she gives birth to a child

______ fertilises an ovum in a female's body.

Blood
Testosterone
A sperm
Seminal fluid

The nutritional requirements of an embryo are maintained through...

ovarian follicle
oviduct
mouth
umbilical cord

In humans, generally, the birth takes place after ______ of embryo development.

14 weeks
28 weeks
40 weeks
280 weeks

The calculation of embryo development (age of embryo) starts from...

the first day of last menstrual cycle
the first day of first menstrual cycle
the last day of first menstrual cycle
the last day of last menstrual cycle

Which of the following is a chemical device of birth control ?

Copper-T
Condum
Birth-control pills
Loop

Where are the testes of human male located ?

In abdominal cavity
In vas deferens
In scrotum
In penis

The process of release of egg from ovary is called...

reproduction
ovulation
menstruation
menopause

The period after 45-50 years in woman is known as...

menstruation
gestation
menopause
lactation

How many days are there in one menstrual cycle ?

31
32-35
28-32
22-40

The period from the formation of embryo to birth is known as...

gestation
parturition
lactation
fertilisation

Every organism produces another identical organism. This event is known as...

growth
reproduction
alteration of generation
regeneration

The method by which the desired characters of two plants can be combined is...

cutting
layering
budding
grafting

During embryo development, the embryo is protected by...

amnion
placenta
umbilical cord
oviduct

ANSWERS TO MCQs:

(1) C (2) A (3) D (4) D (5) B (6) B (7) A (8) D (9) B (10) D (11) A (12) D (13) D (14) B (15) B (16) C (17) C (18) C (19) D (20) B (21) A (22) B (23) A (24) D (25) C (26) B (27) B (28) C (29) C (30) A (31) B (32) C (33) D (34) B

SHORT QUESTIONS

ANSWER IN SHORT:

What is reproduction ?

ANS : The process by which the organisms produce new organisms similar to them is known as reproduction.

Why is reproduction essential ?

ANS : Reproduction is essential for the perpetuation of species and thereby life.

Mention the types of reproduction.

ANS : Asexual reproduction and sexual reproduction are the two types of reproduction.

What is asexual reproduction ?

ANS : Asexual reproduction is the method of reproduction involving only a single individual (organism),i.e. only one organism is needed for reproduction.

Mention different types of asexual reproduction.

ANS : (i) Fission (ii) Budding (iii) Spore Formation (iv) Regeneration (v) Vegetative propagation, etc are types of asexual reproduction.

Mention two types of reproduction by fission.

ANS : Binary fission and multiple fission are the two types of fission.

What is binary fission ?

ANS :When two independent adult organisms are formed after the division of the nucleus and the cytoplasm of one (mother) cell into two (daughter) cells, the process of reproduction is called binary fission.

Give examples of organisms showing binary fission.

ANS : Amoeba and paramoecium show binary fission.

What is multiple fission ?

ANS :When the nucleus of one (mother) cell divides several times into many (daughter) nuclei, each forming an individual organism, the process is called multiple fission.

Give examples of organisms showing multiple fission.

ANS : Plasmodium and amoeba show multiple fission.

What is budding ?

ANS : Budding is a process of reproduction in which a small protuberance (bud) appearing on an adult cell gradually grows bigger and then behaves as an independent organism after being detached from the (mother) cell.

Give examples of organisms showing budding.

ANS : Yeast and hydra show budding.

What is the similarity between hydra and yeast ?

ANS : both hydra and yeast exhibit budding as the method of reproduction.

Mention some organisms showing spore formation.

ANS : Mucor, rhizopus and penicillium show spore formation.

What is sporangium ?

ANS : Sporangium is a structure developing from fungal hypha and it contains a nucleus (spore) which divides several times forming a large number of spores which develop into new hyphae after falling on the ground.

What is regeneration ?

ANS : The ability of an organism to replace the lost parts of its body is called regeneration.

What is fragmentation ?

ANS : When an organism breaks into two or more pieces after being mature and then each piece grows as an individual organism, the process is known as fragmentation.

Give examples of organisms showing fragmentation.

ANS : Oscillatoria and spirogyra show fragmentation.

What is vegetative propagation ?

ANS : Vegetative propagation is a method of reproduction in which a new plant developes from a part of a root, stem or leaf.

Give examples of plants showing vegetative propagation.

ANS : Potato, sweet potato, bryophyllum, etc. show vegetative propagation.

Mention names of artificial methods of vegetative propagation.

ANS : Cutting, layering, grafting etc are artificial methods of vegetative propagation.

Give examples of some plants in which cutting is used as a method of vegetative propagation.

ANS : Cutting is used as a method of vegetative propagatin for sugarcane, grapes, rose, phalsa, etc.

Give examples of some plants in which layering is used as a method of vegetative propagation.

ANS : layering is used as a method of vegetative propagation for lemon. guaua, hibiscus, jasmine, bougainvillaea, etc.

What is grafting ?

ANS : Grafting is a method of vegetative propagation in which two parts of two different plants are joined together in a specific manner so that they unite to grow as one plant.

What is 'scion' ?

ANS : The portion of the plant which is grafted on other plant is called scion.

What is 'stock' ?

ANS : The plant on which grafting is performed is called stock.

In what circumstances is grafting a better method ?

ANS : Grafting is a better method for plants where seeds are having long dormancy period and poor germination capacity.

At which stage of life the reproductive system of human being becomes functional ? (write one word).

ANS : Puberty.

Mention the age of puberty in male and female human beings.

ANS : The age of puberty in human male is about 13-14 years and that in human female is about 10-12 years.

Mention the names of human gonads.

ANS : Testis (testes) in male and ovary in female are human gonads.

Name the sex hormone of human male.

ANS : Testosteron is the sex hormone of human male.

Which hormones are produced in ovary of human female ?

ANS : Estrogen and progesteron are produced in the ovary of human female.

Which are the two processes referred to as gametogenesis ?

ANS : Spermatogenesis and oogenesis are referred to as gametogenesis.

Mention the optimal temperature for spermatogenesis.

ANS : A temperature 3 °C lower than the body temperature is optimal for spermatogenesis.

What is urinogenital path ?

ANS : Urinogenital path is the common opening through which both urine and the sperms are released.

What is ovulation ?

ANS : The release of an ovum from the ovary by rupturing the ovarian follicle is called ovulation.

What is menstrual cycle ?

ANS : The cycle of events taking place in the ovaries and uterus every 28 days and marked by the flow of blood is called menstrual Cycle.

What is menarche ?

ANS : The commencement of menstruation at puberty in a woman is called menarche.

What is menopause ?

ANS : Menopause is the stage in a woman's life when menstrual flow and other related events stop.

What is fertilisation ?

ANS : The union of the male and female gametes resolting in the formation of zygote is called fertilisation.

Mention the type of fertilisation taking place in humans.

ANS : Internal fertilisation takes place in humans.

Mention the term used for male gamete.

ANS : Sperm.

What indicates that the fertilisation has taken place ?

ANS : The absence of menstrual flow at its regular interval indicates that the fertilisation has occured.

What is implantation ?

ANS : The close attachment of the embryo with the walls of uterus is called implantation.

What is placenta ?

ANS : A special tissue between the uterus wall and the embryo (foetus) that fulfils the nutritional, respiratory and excretory needs of the foetus from mother's body is called placenta.

What is the function of amniotic fluid ?

ANS : The function of amniotic fluid is to protect the foetus against temperature changes and mechanical shocks.

What is gestation ?

ANS : The development of the foetus inside the uterus till birth is called gestation.

What is the average duration of pregnancy (gestation period) in human beings ?

ANS : The average duration of pregnancy in human beings is about 280 days or 40 weeks.

What is parturition ?

ANS : The birth of a fully developed foetus after the completion of gestation period is called parturition.

What is family planning ?

ANS : Family planning is the adoption of various new techniques which prevent fertilisation or pregnancy.

What is Zero (Rhythm) method ?

ANS : Zero or Rhythm method is a natural method of contraception in which sexual intercourse is avoided 3 days before ovulation and 1 day after ovulation.

What is 'coitus interruptus' ?

ANS : Coitus interruptus is a natural method of contraception in which the penis is withdrawn from vagina before ejeculation (of semen).

Mention two natural methods of contraception.

ANS : (i)Zero (Rhythm) method (ii) Coitus interruptus.

What is the full form of IUCD ?

ANS : The full form of IUCD is IntraUterine Contraceptive Device.

What is a contraceptive ?

ANS : A device or a substance that prevents fertilisation during intercourse is called a contraceptive.

What is contraception ?

ANS : Contraception is a method of prevention of fertilisation of ovum (pregnancy).

What is vasectomy ?

ANS : Vasectomy is the process of surgical removal of a small portion of vas deferens of a male to prevent fertilisation.

What is tubectomy ?

ANS : Tubectomy is the process of surgically cutting and tying the Fallopian tube of a female to prevent fertilisation.

What is the full form of WHO ?

ANS : The full form of WHO is World Health Organisation.

Define 'health' according to WHO.

ANS : According to WHO, health is a state of complete physical, mental and social well being and not merely the absence of disease.

What are STDs ?

ANS : The infectious diseases which are spread from an infected person to a healthy person by sexual contact are called Sexually Transmitted Diseases (STDs).

What is gonorrhoea ?

ANS : Gonorrhoea is the inflammation of urinogenital tract causing burning sensation during urination.

Which organism causes gonorrhoea ? (Write the name only).

ANS : Neissena gonorrhoea.

What is syphillis ?

ANS : Syphillis is an STD in which there are lesions in the mucuos membrane urinogenital tract and ulcers on genitalia.

Which organism causes syphillis ?

ANS : Treponema palidium causes syphillis.

What is the full form of AIDS ?

ANS : The full form of AIDS is Acquired
Immuno-Deficiency Syndrome.

Which virus causes AIDS ?

ANS : HIV or Human Immuno-deficiency Virus causes AIDS.

Name two animals that can regenerate their lost body parts.

ANS : Planaria and starfish.

Which two sex hormones are produced by ovary in human female ?

ANS : Progesterone and estrogen are produced by ovary in human female.

Name main sex organs in humans.

ANS : Apair of testes in male and a pair of ovary in female are the main sex organs in humans.

What is an ovary ?

ANS : An ovary is the main sex organ in human female which exists in pair and releases an every month to the fallopian tube.

Give the location and function of placenta.

ANS : Placenta is located between the wall of the uterus and the foetus and its function is to fulfil the nutritional, respiratory, developmental and excretory needs of the foetus by connecting the foetus to mother's body.

What is population control ?

ANS : The prevention of unwanted births by applying proper techniques so that the population does not increase rapidly is called population control.

When does a girl attain puberty ?

ANS : A girl attains puberty at the age of about 10-12 years.

What do you mean by reproductive health ?

ANS : Reproductive health means capacity to reproduce without getting diseases like AIDS, gonorrhoea, syphillis, etc. which are contagious and transmitted sexually.

What is the full form of NACO ?

ANS : The full form of NACO is National AIDS Control Organisation.

REPRODUCTION IN ORGANISMS - II : BRIEF ANSWERS
ANSWER IN BRIEF

What is reproduction ? Mention its importance.
ANS:
The process by which organisms produce new organisms similar to them is known as reproduction.

The importance of reproduction is :

It maintains the existence of each species.
It transfers hereditary characteristics to the next generation.
It brings concomitant changes in evolutionary events.

What is asexual reproduction ? Mention its types(methods).
ANS:The process of reproduction in which any somatic part of the body of a single organism develops into a new organism is called asexual reproduction.

Its types are :

fission
budding
spore formation
regeneration
vegetative propagation

What is vegetative propagation ? Mention its different methods.
ANS:Development of a new plant from the root, stem or leaf is called vegetative propagation.

The different methods of vegetative propagation are :

Cutting
Layering
Grafting

Write a note on fission as a method of reproduction.
ANS:

Fission occurs in unicellular organisms.
It is a method of asexual reproduction.
Binary fission and multiple fission are its two types.
Amoeba, paramoecium,plasmodium,etc. reproduce by fission.

Explain : Binary fission.
ANS:

It is a method of asexual reproduction occurring in unicellular organism.
An organism produces two unicellular organisms identical to the parent cell through mitotic division.
Amoeba, paramoecium,etc. reproduce by binary fission.

Write a note on puberty.
ANS:

Puberty is the stage in the life of a human being when the reproductive organs show gradual change in structure and they become functional.
A boy attains puberty at the age of 13-14 years whereas a girl attains it at the age of 10-12 years.
During puberty,testes in male start producing sperms and sex hormone testosterone.
Similarly, ovaries in female start producing ovum and sex hormones estrogen and progesterone.

Mention accessory reproductive glands and their function in human male.
ANS:Seminal vesicle,prostate gland and bulbourethral gland are the accessory reproductive glands in human male. The secretions of these glands form semen which provides movement to sperms so that they can reach the egg cell easily.

Mention the requirements of fertilisation of an ovum.
ANS:

Ovulation must have occurred and hence the ovum must be present in the oviduct.
Copulation must occur before the ovum gets destroyed.
A sperm must reach the ovum to fertilise it.

Why is population control needed ?
ANS:Population control is needed to control population growth which is the biggest problem in the world. Also, frequent deliveries can be dangerous for the health of a female and they can result in the birth of a weak(unhealthy) child.

Mention symptoms of STDs (Sexually Transmitted Diseases).
ANS:

Inflammation of urinary tract and hence pain at the time of passing urine.
Lesions on skin of the urinary tract.
Itching sensation in penis or vagina.
Lesions on genital passage.

What individual care should one take to prevent STDs ?
ANS:

One should keep awareness about the cleanliness of reproductive organs.
There must be limit in developing friendship with opposite sex.
One should use birth-control tools during intercourse to prevent such diseases.
One should learn to keep control on sexual desires.
Morality must be imposed as a religious practice.

Distinguish between menarche and menopause.

ANS:

REPRODUCTION IN ORGANISMS - III : LONG ANSWERS
GIVE ANSWER IN DETAIL

Describe fission as a method of reproduction.

ANS :Fission occurs in unicellular organisms. Binary fission and multiple fission are its two types.

BINARY FISSION :

An organism produces two unicellular organisms identical to the parent cell through mitotic division.
Amoeba, paramoecium, etc. reproduce by binary fission.

MULTIPLE FISSION :

Under certain circumstances, the nucleus of a cell divides several times within the cell forming many nuclei.
Each nucleus is then surrounded by cytoplasm to form a separate unit.
All these newly formed cells then come out of the mother cell(parent cell) by breaking the wall and behave as a new organism.
Plasmodium, amoeba, paramoecium, etc. exhibit such reproductive event.

Describe budding as a method of reproduction.

ANS :

Budding is observed in both unicellular and multicellular organisms.
In unicellular organisms, some part of the body swells out at one point and developes into a 'bud' due to the formation of nucleus and cytoplasm within it. This bud then separates from the parent cell and behaves as an independent organism. Sometimes the buds form a chain before being separated. Example : yeast.
In multicellular organisms like hydra, a part of its cylindrical body swells and develops into a bud. This bud then grows and separates from the mother's body to develop as an independent daughter animal.

Describe spore formation as a method of reproduction.

ANS :

Spore formation is the most common method of asexual reproduction in majority of bacteria and fungi.
During spore formation, a structure called sporangium develops from fungal hypha which is a filamentous structure.
The nucleus in sporangium divides several times and forms many nuclei.
Each nucleus gets surrounded by cytoplasm and forms small unicellular structure called spore.
When sporangium bursts, the spores spread into the surrounding environment and germinate into new hypha forming mycellium which behaves as new organism.
Mucor and Rhizopus reproduce by this method.

Describe regeneration as a method of reproduction.

ANS :

Regeneration is the ability of an organism to reproduce the lost parts of its body.
When some body part of an organism breaks suddenly, a new part similar to the lost (broken) part is created at the point of breaking after some time.
All broken parts thus develop into new organisms.
Hydra, planaria, sponge and starfish reproduce by regeneration.
Some filamentous algae increase their number by this method. Algae filaments break frequently and each broken piece develops into independent algae. This is called fragmentation.

Describe role of sex hormones in humans.

ANS :

Once a male reaches puberty, testes start producing sex hormone testosterone. Similarly, in females, ovaries start producing sex hormones estrogen and progesterone.
These hormones play an important role in the regulation of the processes of spermatogenesis (in male) and oogenesis (in female).
Sex hormones are also responsible for the structural development, maintenance and functions of accessory sex organs.
They induce secondary sexual characters at proper age.
The secondary sexual characters in male include : growth of hair on face, chest and other body parts; change in voice, aggressive behaviour and mental agitation.
Those in female include : changes in face and body, development of mammary glands, change in the pitch of voice, vigilant behaviour and sentimental approach.

What is the difference between menstruation and menopause ?

ANS :When a woman (girl) attains puberty, her reproductive system becomes functional. As a result the ovary starts releasing ovum and this phenomenon is repeated after a definite period as a cycle. When an ovum is released the uterine wall gets ready for the implantation of fertilised ovum (zygote). If the ovum is not fertilised within certain period, it gets destroyed and the uterine wall disintegrates resulting in the breaking of blood vessels. The disintegrated tissue along with blood flows out through vagina. This flow of blood continues for about 3-5 days and is called menstruation.

Menstruation, as a part of sexual cycle, starts at the age of about 10-12 years and its commencement indicates that the reproductive system of the woman has become active. The reproductive system then remains active up to the age of about 45-50 years and then becomes non-functional. The sexual cycle stops and menstruation ceases. This is called menopause. Thus, menopause marks the end of reproductive period of a woman.

Describe vegetative propagation in detail.

ANS :

Development of a new plant from root, stem or leaf is called vegetative propagation.
Some higher plants exhibit this method of reproduction.
Examples : (i)Development of buds from the root of sweet potato.(ii)Development of buds on potato tuber.(iii)Development of buds on the margin of bryophyllum leaf.
Besides natural method, artificial vegetative propagation is also used to increase production. Cutting, layering and grafting are commonly used methods of artificial vegetative propagation.

Describe various methods of artificial vegetative propagation.

ANS :

CUTTING :

In this method, a piece of root, stem, leaf or sometimes a bud is sown in soil which develops into a new plant.
The piece of the plant sown in the soil develops roots downwards in the soil and aerial organs in the external environment.
this method is useful for large scale production which is greatly economical and profitable.
Example : sugarcane, grapes, rose, phalsa.

LAYERING :

In this method, a branch of stem of a plant is bent towards the soil in such a way that some part of the branch remains inside the soil and its tip remains outside.
The part covered by the soil develops roots.
When this part is detached from the parent plant, it grows independently into a new daughter plant.
Example : Lemon, guaua, hibiscus, jasmine and bougainvillaea.
In plants like strawberry and raspberry, sometimes a branch comes into contact of the soil naturally and develops as a daughter plant after producing roots.

GRAFTING :

Grafting is a method in which two parts of different plants are joined together in such a way that they unite to grow as one plant.
A part of an adult (mature) plant is tied up with a unit of soft plant to get early flowering in the soft plant.
The portion of the plant having roots on which grafting is performed is called 'stock'.
The portion of the plant which is grafted on the other plant is called 'scion'.
By this method, desirable characteristics of different plants can be combined.
This method is very useful for plants whose seeds have long dormancy period and poor germination capacity.
Example : On the stock of lemon, a scion of lemon or orange can be grafted. This method is widely used to increase the production of mango.

Describe reproductive system in human male.

ANS :

A pair of testes is the main reproductive organ in human male.
Vas deferens and penis are the accessory reproductive organs.
Seminal vesicle, prostate gland and bulbourethral gland are the accessory reproductive glands.
The two testes lie in a muscular sac called scrotum outside the abdominal cavity in the region between legs.
The temperature in the scrotum is 3°C lower than that of the body. This temperature is suitable for the process of spermatogenesis.
The sperms produced in the testes are transported through vas deferens to the penis.
Sperms mix with the semen which is formed by the secretions of reproductive glands.
Semen provides movement to sperms so that they can reach the egg cell(ovum).
In male, urine and sperms get released through the same path called urinogenital path.

Describe reproductive system in human female.

ANS :

The main reproductive organ in human female is a pair of ovaries located in the abdominal cavity.
The reproductive system includes ovaries, fallopian tube (oviduct), uterus, cervix, vagina and vaginal opening.
Accessory reproductive organs include labia major, labia minor and clitoris.
Ovaries possess many ovarian follicles which become mature at puberty stage and form graffian follicle. Graffian follicle form the structure of ovum.
Generally, one ovarian follicle becomes active alternately and forms one ovum.
The free end of the oviduct towards ovary is fimbricated and funnel shaped. It is known as oviductal funnel.
The oviducts on both sides join in the middle to form inverted triangular shaped muscular sac called uterus. The mouth of uterus opens into vagina through narrow cervix.
Vagina opens outside the body through vaginal opening.
There is a separate urinary opening above the vaginal opening. Thus, in female, the urinary passage and genital passage are separate from each other.

Describe sexual cycle in human female.

ANS :

The sexual cycle in female starts at puberty stage when the development of ovum starts in ovary from ovarian follicle.
When the ovum develops (matures) up to a definite stage it is released by rupturing of ovarian follicle. This is called ovulation.
During first 13 days of cycle, development of ovum occurs and ovulation takes place on the 14th day. After ovulation, the ovum enters oviduct through oviductal funnel.
Simultaneously, the walls of uterus get ready for the implantation of embryo.
If fertilisation occurs, the implantation of embryo on the walls of uterus takes place and the process of supply of nutrition to embryo starts.
If fertilisation does not occur, the walls of uterus that got prepared for implantation in the form of blood-filled tissues start disintegrating.
This results in the breakdown of blood vessels and the broken uterine wall tissues come out through vagina along with blood. This is known as Menstruation.
Menstruation may last for 3-5 days during which abdominal pain is experienced.
Then the cycle is repeated. Generally menstruation cycle is repeated every 28-32 days.
The secretion of sex hormones at puberty stage is responsible for the commencement of menstrual cycle. With this the female attains the ability of conception.
The sexual cycle generally remains functional up to the age of 45-50 years. Then gradually the sexual cycle stops due to hormonal changes and menopause starts indicating the loss of the ability of conception.

Describe fertilisation and embryo development in humans.

ANS :

During the sexual cycle of a female ovulation occurs on the 14th day and the ovum enters the fallopian tube.
If copulation occurs during the period when the ovum is present in the oviduct, sperms released in semen try to reach the ovum with the help of the fluid substances present in semen.
If one of the sperms can reach the egg(ovum) in the oviduct, then fertilisation takes place.
If fertilisation occurs, then the walls of uterus start further developments.
The embryo(fertilised egg) reaches the walls of the uterus and gets implanted on the wall.
An umbilical cord develops from the embryo to the uterine wall and supplies nutrition to the embryo from mother's body.
For the protection of the developing embryo, a structure (amnion) filled with amniotic fluid develops.
The birth of the child takes place, usually, after 40 weeks or 280 days. (this is the time for the development of the embryo into a mature baby).
Duration from zygote formation till birth of the child is called embryo developing time.
When the development of the embryo is complete, a new born child comes out of the mother's body by breaking the amnion. This event is known as delivery.
The calculation of embryo development time starts from the first day of last menstrual cycle.
The normal weight of the foetus(at the time of birth) should be about 3-3.5 kg.

Write an explanatory note on population control.

ANS :

Growth of population is one of the biggest problems in the world. The population of India has crossed 1 billion mark and it needs serious attention . Also, frequent delivery can be dangerous to both the mother and the child as it results in ill health and the birth of a weak baby.
Keeping the growth rate of population limited by using some scientific devices is called population control.
Types of such devices include : (i) Birth-control tools (ii) Chemical devices (iii) Surgical devices.
Birth-control tools :
A condom used by males prevents the entry of semen into vagina during copulation.
A copper-T or a loop used by a female prevents implantation in uterus.
Chemical devices include birth-control pills containing hormones which prevent implantation.
Surgical methods :
In males, the vas deferens is cut and tied up to prevent the transport of sperms. The method is called Vasectomy.
In females, the oviduct is cut and tied up to prevent the transport of ovum. The method is called Tubectomy.
A doctor must be consulted before following any method of population control to avoid side effects.

Write a note on sexually transmitted diseases (STDs).

ANS :

Sexually transmitted diseases are infectious and some times they prove fatal.
The diseases occurring due to unsafe sexual intercourse are called Sexually Transmitted Diseases(STDs).
Such diseases are caused by virus, bacteria, fungi and protozoans.
Syphillis is caused by Treponema Palidium.
Gonorrhoea is caused by Neissena Gonorrhoea.
Symptoms of STDs :
Inflammation of the passage of urine.
Lesions on the skin of urinary tract and vagina.
Itching sensation in penis or vagina.
Lesions on genital passage.
STDs are curable by proper treatment, so a doctor must be consulted immediately without hesitation when any of the symptoms of STDs become visible.
AIDS can prove fatal. Research work is in progress to find out medicines to cure AIDS.
WHO has given several guidences to prevent the spread of STDs and to protect human race.
In India, NACO (National AIDS Control Organisation) and other NGOs (Non-Government Organisations) are functioning to create awareness about STDs.
Individual Care :

One should keep awareness about the cleanliness of the reproductive organs.
There must be limit in developing friendship with opposite sex.
Use of birth-control tools during intercourse can prevent such diseases.
The best one is to learn to keep control on sexual desires.
Morality must be imposed as religious practice.