Sexual Reproduction in Human Beings
| Mitosis | Meosis |
| * Produce genetically identical cells | * Produce genetically unique cells |
| * Results in diaploid cells | * Results in haploid cells |
| * Take place throughout an organism's lifetime | * Take place only at a certain time of an organism's life cycle |
| * Involved in asexual reproduction | * Involved in asexual reproduction |
Note:- Both male and female gametes are formed during the process of sexual reproduction called
meiosis.
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Sperm |
Ovum |
|
* It is a male gamete. |
* It is a female gamete. |
|
* it is smaller than ovum. |
* it is larger than sperm. |
|
* it has long tail (flagellum) and a head. |
* It is generally spherical in shape. |
|
* It is mobile in nature. |
* It is immobile in nature. |
|
* It is the smallest cell in human body. |
* It is the largest cell in human body. |
|
Haploid Cell |
Diploid Cell |
|
* It is represented by ‘n’. |
* It is represented by ‘2n’ |
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* One nucleus is present. |
* Two nucleus are present. |
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* There are 23 in numbers one on each pair of chromosome. |
* There are 46 in numbers one on each pair of male and female chromosome. |
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* Gametes are haploid. |
* Somatic cells are diploid. |
|
e.g. Male and Female gametes i.e. Sperm & Ovum |
e.g. Body Cells such as Nerve, Muscles, Bones, Zygote, etc. |
Fertilisation are two types:-
| External Fetilisation | Internal Fetilisation |
|
* It occurs outside the female body. |
* It occurs inside the female body. |
| * A large numbers of gametes are released into the sourrounding (water) where fertilisation takes place. | * The male gametes are deposited in the body of the female with the help of the copulatory organ. |
| * Water medium is needed for the sperm to be able to unite with the egg. | * Water medium is not needed. |
* The number of gametes produced is large. |
* The number of gametes produced is less. |
| * e.g. Bony fish, Amphibian, most of the Algae, etc. | * e.g. Reptiles, Birds, Mammals, Gymnosperms,Angiosperms, etc. |
* Chromosomes- The thread like structure present inside the nucleus which carries the information of heredity from parents to their offspring are called chromosomes.
It contain DNA in which gene is stored.
* Primary sex organs- The organs which produce the gametes are called primary sex organs.
e.g. Testes and Ovaries
* Secondary sex organs- The organs which do not produce the gametes are called secondary sex organs.
e.g. Urethra, Seminal vesicles, Fallopian tube Penis, etc.
Note:- Puberty is a stage in which a child's body begins to develop and change as they become an adult.
-> In other words, it is the time in life when a boy or girl becomes sexually mature.
-> It is a process that usually happens between ages 10 to 14 for girls and ages 12 to 16 for boys.
Male reproductive system
-> It causes physical changes, and affects boys and girls differently.
Q) Write few differences between male and female during puberty.
It consists of:-
* Testes * Scrotum * Epididymis * Vas deferens * Urethra * Penis
Testes
-> Generally oval in shape and exist in pair.
-> Sperm is produced inside testes.
* Function- It release testosterone hormones which help in the regulation of male sex organ and secondary sexual characters like a moustache, beard and voice.
Scrotum
-> Loose sac like structure in which testes or testicles are present is called scrotum or sacrotal sac.
* Function- It protect the testes and maintain a low level temperature as compared to body temperature.
Epididymis
-> It is a coiled tube which is long and is placed on the rear of each testicle.
* Function- It store and transport sperm cells which is created in the testes.
Vas deferens
-> Epididymis later connect to a tube called
vas-deferens.
-> It is basically a muscular, long tube which begins from the epididymis and travels to the pelvic cavity.
* Function- It helps to transport the mature sperm to urethra.
Urethra
-> Small tube like structure in which semen is present is called urethra.
-> Whenever the penis gets erect at the time of sexual intercourse, the urine flow is blocked by the urethra and ejaculating semen.
Note:- Semen is a mixture of sperm and fluid which is secreted by seminal vesicles.
Fluid provide nourishment to the sperm.
* Function- It also carries urine from urinary bladder to outside the body and also help to release the sperm during sexual intercourse.
Penis
-> It is a muscular organ which is used to pass urine as well as to deliver sperm into the vagina of female body.
Erectile tissue
-> The body of the penis is cylindrical in shape and consists of three internal chambers.
These chambers are made up of special, sponge-like tissue called erectile tissue.
So,
-> Erectile tissue contains thousands of large spaces that fill with blood when the man is sexually aroused.
As the penis fills with blood, it becomes rigid and erect, which allows for penetration during sexual intercourse.
Beside, there are three reproductive gland that play an important role in the process of gametogenesis.
-> Gametogenesis is the process in which haploid cells(n) is formed by a diploid cells(2n).
Explanation
-> Gametogenesis refers to the formation of two types of gametes- male and female gamete.
The process of formation of male gamete “sperm” in humans is called as spermatogenesis while the process of formation of female gamete “ovum” is called as Oogenesis.
Functions of three reproductive glands are:-
* Seminal vesicle- It secrete a significant proportion of the fluid that ultimately becomes the semen when mixed with sperm.
* Prostate gland- It secrete a slightly alkaline fluid, milky or white fluid, which protects the sperm from the acidic environment in female vaginal tract.
It also provide nourishment and energy to the sperm.
* Cowpers gland- It produce a fluid that leaves the urethra in order to neutralize the acid left from the urine because the sperm doesn’t survive in acidic medium, it only survive in basic or alkaline medium.
Female reproductive system
It consists of:-
* Ovaries * Vagina
* Fallopian tube
* Uterus
-> Primary female sex organ is called ovaries.
-> They are two in number and located one on each side of uterus or lower abdomen.
-> They produce female gametes.
* Function- It secrete female hormone oestrogen or estrogen and progesterone.
Function of estrogen
* It helps in the development of female secondary sex characteristics, such as breasts, wider hips, pubic hair and armpit hair.
* It also helps to regulate the menstrual cycle.
Function of progesterone
* It is the hormone secreted by the ovaries which regulate the condition of the inner lining
“endometrium” of the uterus.
* It also helps in the development of the foetus.
Fallopian tube
-> They are narrow muscular tubes which attach to the upper portion of the uterus.
-> They exist in pair.
-> Fallopian tube is also called oviduct.
* Function- Fallopian tubes act as tunnels for the egg cells. Therefore, they transport the egg cell from the ovaries the to uterus.
Uterus
-> It is a pear-shaped, hollow organ which is “home” for a developing fetus or foetus.
A fetus is a developing baby beginning in the 11th week of pregnancy.
-> It is also called womb.
-> The uterus separates into two parts:-
(i) The cervix (ii) The corpus
* Function- It helps in the development of foetus and hold the baby for nine months.
Some important points:-
* Fundus- The top portion of uterus is called fundus.
Function- It host a fertilized embryo as it grows into a baby.
* Uterine cavity- The cavity present inside the uterus is called uterine cavity.
It is important in the act of sex, fertilization and pregnancy. This cavity allows for a sperm to travel toward eggs. So,
Function- It implant the fertilised egg which
develop during pregnancy.
* Myometrium- It is the middle layer of the uterine wall.
* Endometrium- It is the innermost layer of the
uterine wall.
Function- It prevent adhesions between the
opposed walls of the myometrium, and help in
maintaining the patency of the uterine cavity.
* Cervix- A narrow passage forming the lower end of the uterus is called cervix.
Function- It acts as the door to the uterus which sperm can travel through to fertilize eggs.
When your body is not carrying a child, your cervix helps keep unhealthy things out of your body, like
tampons and bath water.
* Corpus- It is a general term used in biology to mostly denote the more prominent portion, or a portion that occupies maximum space, of a
structure, mostly organs.
In some places it might be used just to mean a body or a mass, irrespective of relative size of the structure. So,
Corpus of uterus may be define as the maximum space present in the uterus is called corpus.
Vagina
-> It is a canal which joins the cervix to the external portion of the body. You can even call it as the birth canal. Sperm is released here.
Function
-> It takes menstrual flow outside the body.
-> It is involved in sexual intercourse.
-> It acts as a birth canal during delivery.
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