Organism that produces sexually via the production of sex cells called gametes. In human, male sex cells called spermatozoa (sperm cell) are relatively motile. Female sex cells are called ova or eggs are non-motile. Ova are lager then male gametes. Zygotes are formed when these cells fuse in a process called fertilization.
- Primary sex organs: The sex organs which produce the germ cells or gametes are called primary sex organs. They are testis in males and ovaries in female.
- Secondary sex organs: The sex organs which conduct and nourish the gametes are called secondary sex organs.
Male Reproductive System
This system includes a pair of testis vas deferens, urethra and a muscular organ penis.
- Testis: A pair of testis is placed in a structure called scrotum which is located outside the abdominal cavity because sperm formation requires a lower temperature then the normal body temperature. The sperm are tiny bodies that consist of genetic material and a long tail that helps to move towards the female germ cell. Testosterone hormones are secreted by testis.
- Vas deferens: Sperm duct is called vas deferens. They are 2 in numbers each one arising from testis placed on either side. The transport sperm into penis. Sperm along with fluid secreted by different glands form thick liquid called as semen. Semen is conveyed to urethra through which it is discharged outside. Prostate gland and seminal vessels secrets semen to make the movement of sperm.
- Urethra: Urethra forms a common passage for both the sperm and urine as it is just one tube that connects both the glands i.e. urinary bladder and vas deferens.
- Penis: It is a muscular organ which transfers semen into female reproductive tract. Penis receives both urinary tube and sperm duct and serves as a common transporting organ for urine and semen. It is underlined by the blood vessels which gives continuous supply of blood.
Female Reproductive System
This system includes a pair of ovaries, a pair of oviducts, uterus, cervix and vagina.
- Ovary: A pair of ovaries forms the gonads in female. They are oval shaped and are close to kidney. Ovaries are the female sex organs that lie one on the either side of the abdominal cavity. Ovaries by the process of oogenesis form eggs or ova which are released as one per month. Ovaries produces two hormones, oestrogen and progesterone Ovaries have thousands of follicles. After puberty these follicles develop into eggs.
- Oviducts: A tube like structure arising from each ovary on either side is called as oviducts. This is also called as fallopian tube. The eggs carried from the ovary to the uterus through a thin oviduct called fallopian tube. The two oviducts combine and open into an elastic bag like structure known as the uterus.
- Uterus: It is a hollow muscular organ which has the capacity to bear the child. It is also called a womb. Zygote formed after fertilisation in the fallopian tube travels downward by dividing itself continuously to form an embryo. Embryo a it reaches the uterus gets implanted into the wall for the uterus. Ager fertilisation, female reproductive hormones bring in many changes to the uterus, so as to bear the growing embryo. This embryo transforms into foetus after growing.
- Cervix: It is located at the top of vagina. It is junction between the vagina and uterus.
- Vagina: It is located at the end of the uterus in the female reproductive tract. It is also known as the birth canal and it opens outside the body. Vagina secrets mucous to keep the tract wet. It opens out through vulva.
Process of Reproduction
The Process of reproduction includes:
- Fertilization: During copulation, millions of sperms are released into the vagina. Sperms are highly active and motile, they move up to fallopian tube. Most to the sperm are destroyed by the female secretions. The few sperms that have survived make it to the ovum present in the fallopian tube. Only one sperm and one egg are involved in fertilisation. Once one sperm enters the egg, the egg forms a membrane that prevents other sperm from entering. The sperm fuses with the ovum to fertilization and form zygote.
- Implantation: After 6 to 9 days of fertilization zygote descends from the fallopian tube into the uterus. The zygote will attaches itself to the urine wall. The inner wall of the uterus develops and partially envelops the embryo. This process is called Implantation. A woman with an embryo developing in her uterus is called pregnant.
- Gestation period: The period during which eth embryo development take place in the uterus is called Gestation period. The development of the child inside the mother’s body takes approx. 9 months i.e. 36 weeks.
- Birth: Few days before birth, the foetus moves in the uterus until its head point towards the cervix. The child is born due to contraction of the uterine. The abdominal muscles are at regular intervals are called labour. The child comes outside from the vagina. After the baby is born, the placenta and the urine lining are discharged through mensuration.
The mensuration cycle is a series of changes of woman’s body goes through to prepare for a pregnancy. Mensuration lasts for the first 3-4 days. During this phase, the inner lining of the uterus is shed which causes the blood vessels to rupture. This is cause of bleeding and is called mensuration. It stops by the age of 45-50 years and is called menopause. The ovary produces one egg in every 28 days therefore mensuration occurs after every 28 days in female.
During process of reproduction, some diseases can be transmitted b/w males and females from infected person to the healthy person. These diseases are known as STD’s i.e. Sexually Transmitted Diseases. Some STD’s are Aids (Acquired Immuno Deficiency Syndrome), Gonorrhoea, syphilis, Genital herpes etc.