- 1 Reproductive cycle
- 1.1 Male reproductive cycle of mammals
- 1.2 Luteinizing hormone (LH)
- 1.3 Androgens
- 1.4 Female reproductive cycle of mammals
- 1.5 Follicle stimulating hormone (FSH)
- 1.6 Luteinizing hormone (LH)
- 1.7 Functions of female sex hormones
- 1.8 Functions of progesterone
- 1.9 Menstrual cycle
- 1.10 Estrous cycle
- 1.11 Copulation and Fertilization
- 1.12 Implantation and pregnancy
- 1.13 Parturition
The reproductive cycle of male and female is a natural changes that occurs in the male and the female reproductive system respectively.
Male reproductive system consists of a pair of testes (primary reproductive organ of male) which produces million of sperm naturally after maturation.
Female reproductive system consists of a pair of ovaries (primary organ of female) which produces female sex cell or egg alternately each month after maturation.
Male reproductive cycle of mammals
It includes the development of testis, epididymis, vasa-differentia, urethra, ejaculatory duct, seminal vesicle, prostate gland, Cowper gland (Bulbourethral gland), enlargement of penis, development of axillary or pubic hair.
The development of these organs is controlled and regulated by male sex hormones called androgens secreted by interstitial cells of testis and as well as FSH and LH hormones of pituitary gland.Follicle stimulating hormone (FSH) This hormone controls the growth of testis and process of spermatogenesis or sperm formation.
Luteinizing hormone (LH)
It stimulates the activity of interstitial cell and thus controls the production of testosterone, which in turn controls the spermatogenesis and promotes the development of accessory sex organs.
It is secreted by the interstitial cells and adrenal cortex promotes the growth and functions of male sex organs like epididymis, vas deferens, seminal vesicles, Penis and development of accessory sex organs. Androgens also facilitate spermatogenesis and maturation of sperm.
Female reproductive cycle of mammals
The female reproductive system consists of a pair of ovaries, a duct system consisting of a pair of fallopian tubes, a uterus, cervix and vagina. A pair of mammary glands are accessory genital glands of female reproductive system.
Follicle stimulating hormone (FSH)
Follicle stimulating hormone secreted by pituitary gland.
It increases the size and numbers of Graafian follicles and causes their ripening.
It also induces the secretion of oestrone or oestrogens, formation of ovum and the formation of oestrus.
Luteinizing hormone (LH)
Luteinizing hormone is also secreted by pituitary gland.
L.H. causes the growth and persistence of corpus luteum and also induces the secretion of progesterone.
It is responsible for final maturation of ovarian follicles, ovulation and initial formation.
Indirectly, it stops oestrus Cycle and helps the implantation of ovum into the uterus.
It maintains normal pregnancy.
Functions of female sex hormones
Oestrogens bring about the growth of uterus, vagina, development of breasts, menstrual changes and the appearance of secondary sexual characters stimulate the growth of axillary and pubic hair.
They are also responsible for the growth of uterus and mammary glands during pregnancy.
They increase the sensitiveness of the uterine muscles to the action of oxytocin.
Oestrogen controls menstrual reproductive cycle by inducing endometrium and increase secretion of mucus by survical glands.
Estrogens increase musculature of fallopian tube, their contractility and motility.
These are responsible for the maintenance of corpus luteum.
Functions of progesterone
It is produced by corpus luteum as well as from placenta, it has the following functions.
It is responsible for the pre-menstrual uterine mucosa.
It is essential for pregnancy.
It enhances breast development during pregnancy.
It inhibits ovulation after fertilisation of egg.
It also causes enlargement of birth canal by growth of vagina and relaxation of pelvic ligament.
Menstrual cycle occurs in primates.
During menstrual cycle, Rhythmic series of changes occur in the sex organ of female, throughout the reproductive life of women from puberty.
During menstrual cycle, cyclical discharge of blood, mucus and certain other substances at an average interval of 28 days. The phase of menstrual cycle, uterine blooding occurs about 35 days.
It occurs in non-primate mammals.
Copulation and Fertilization
Male and female copulates and after copulation, fertilization occurs in the fallopian tubules.
Implantation and pregnancy
As soon as the embryo is established in the uterine wall through placenta, the production of gonadotrophic hormones increases. These are produced by the placenta.
The placenta also produces a large amount of oestrogen and progesterone.
These further increase the thickness of uterine wall, vagina and mammary glands.
Prolactin or Luteotropic or Lactogenic hormone (LTH) or anterior pituitary maintains the corpus luteum, and stimulates the corpus luteum to produce progesterone.
During pregnancy, further growth of Graafian follicles and ovulation is prevented because the large amounts of oestrogen produced by the placenta inhibit the anterior pituitary to produce follicle stimulating hormone (FSH).
At the end of gestation period parturition of the embryo from the uterine wall is also controlled by the hormonal activity.
It brought about by the powerful intermittent contraction of the myometrium.
The progesterone has an inhibitory effect on the uterine motility and thus counteracts.
The effect of oxytocin hormone secreted by the posterior lobe of the pituitary gland.
The mammary glands are prepared for pregnancy by the action of oestrogen or progesterone hormone.