Hormones and Reproductive Function

Hormones are chemical messengers that regulate most functions in the human body. Endocrine glands or ductless glands secrete hormones directly into the bloodstream. Sex hormones control the onset of puberty and initiate the reproduction function. Body changes such as the growth of facial hair and cracking of voice, are initiated due to the secretion of testosterone. Body changes in females during puberty, such as breast development, are initiated by estrogen. At puberty, the level of sex hormones is sufficient to bring about the maturation of gametes, sperm and ovum. The reproductive phase of life lasts longer in males than in females. Menarche is the first occurrence of menstruation. The shedding of the uterine thickening along with its blood vessels is menstruation.
Menopause is the stoppage of menstruation. Fertilisation is the fusion of a sperm and an ovum.

The menstrual cycle takes place every 28-30 days. Sex chromosomes in sperms determine the baby’s gender. Humans have 23 pairs of chromosomes in each cell.
A gamete is a mature reproductive cell - a sperm or an ovum. Gender determination of an unborn baby is considered illegal in India. Goitre is caused by the enlargement of the thyroid gland. Insulin deficiency causes diabetes. The thyroid gland produces thyroxine and calcitonin. The adrenal glands secrete adrenalin. The pituitary gland is the master gland and controls all the endocrine glands. The life cycle of the silk moth is controlled by insect hormones. Thyroxine is responsible for metamorphosis of the larva or tadpoles into adult frogs.