Human Reproductive System

By | April 6, 2016
  • Human reproductive system becomes functional at a definite age called puberty. Normally, males attain puberty at the age of 13 to 14 years, while females attain puberty at the age of 10 to 12 years.
  • Testis is the primary sexual organ of male whereas ovary is primary sexual organ of female.
  • The male gonad produces sperm and female gonad produces ovum at the age of puberty. The testes and ovary, besides producing viable gametes, also secret hormones. These are testosterone (male hormones from testes) and estrogen (female hormone from ovary).
  • All animals and plants are made up of cells. The cells have nucleus which contains a large number of paired thread like structures called chromosomes.
  • In human beings there are 23 pairs of chromosomes. Chromosomes carry the determinants of the body that are genes.
  • 22 pairs of chromosomes in human cells called autonomous are alike in men and women, they determine the features like color of skin, hair and eyes, shape of body organs.
  • 23rd pair, called the pair of sex chromosomes consists of two similar members in women XX,. In men the two members are dissimilar i.e. XY.
  • Two microscopic specks of life one from the father constitutes life each called a gamete.
  • Male gamete is called sperm which is roughly about 0.008mm. It is charged with an unimaginable store of energy. It swims for 12 cm journey up to the ovum which is equivalent of a man’s 5 mile swim upstream a river.
  • About 5 hundred millions sperms are deposited at a time so that at least one is likely to find the ovum.
  • Female gamete is called ovum or egg cell formed at ovaries. It is the largest of human cells. It is roughly about 0.13 mm in diameter and 0.000004 gm in weight.
  • Usually one ovum is shed from the ovary every month. During the reproductive age of women about 400 ova are produced in a life time.
  • For production of sperms testes require temperature at least 1°C less than the body temperature.
  • Testes produce testosterone (hormone) along with sperms.

Know more about
Female Reproductive System
Male Reproductive System

Fertilization

  • In human beings, fertilization is internal. The male gamete (sperm) is introduced inside the female genital tract b y the process called copulation (mating). The sperms are highly active and mobile. millions of sperms are released in vagina and they move up through cervix and uterus. finally in the fallopian tube only one sperm fertilizes the ovum. After the union of the sperm and the ovum  (fertilization) zygote is formed, if copulation has taken place during ovulatory period (middle of the menstrual cycle). Fertilization is marked by the absence of the menstrual flow.
  • The embroynic development of the zygote starts immediately in the fallopian tube and pregnancy begins. The embryo moves down to reach the uterus and gets attached to its thickened inner wall. The close attachment of the embryo with the uterus is called implementation After implementation, a special tissue develops between uterine wall and the embryo (foetus) called placenta. Through the placenta, the development needs of the foetus, such as nutritional, respiratory and excretory are met from the maternal body. The development of foetus inside the uterus till birth is called gestation. On completion of gestation, the birth of the fully developed foetus is termed as parturition. The average duration of human pregnancy is about 280 days or 40 weeks and it is calculated from the first day of the last menstrual cycle. The normal new born child, after 40 weeks of gestation, weighs about 3.5 kg.