Hormones in Reproduction

Understanding Hormones

Hormones are chemicals produced by glands in the endocrine system and travel through the bloodstream to target cells.
They play a vital role in various bodily functions, including reproduction.

The Menstrual Cycle

The menstrual cycle is the series of changes a woman’s body goes through to prepare for a possible pregnancy.
The cycle is controlled by hormones including oestrogen, progesterone, follicle-stimulating hormone (FSH), and luteinising hormone (LH).
FSH is released by the pituitary gland and causes an egg to mature in one of the ovaries. It also stimulates the ovaries to release oestrogen.
Oestrogen causes the lining of the uterus to thicken and grow. It also inhibits FSH and stimulates the release of LH.
The surge in LH causes ovulation, the release of the mature egg from the ovary.
After ovulation, the remnant of the follicle in the ovary produces progesterone, which maintains the thick uterine lining in preparation for possible pregnancy.

The Role of Hormones in Pregnancy

If an egg is fertilised, the embryo produces a hormone called human chorionic gonadotropin (hCG), making the ovary continue producing progesterone.
If the egg is not fertilised, lowered levels of progesterone cause the lining of the uterus to break down, marking the start of the menstrual period.

Hormone Control in Reproduction

The pituitary gland, located at the base of the brain, produces hormones that control other glands, including the ovaries and testes.
In men, the pituitary gland produces luteinising hormone (LH) which triggers testosterone production.
Testosterone stimulates sperm production and is responsible for secondary sexual characteristics during puberty.

Getting familiar with how hormones operate within the reproductive system will give you a solid foundation for understanding reproduction and its associated processes. Particularly noteworthy is the menstrual cycle and the role of hormones in pregnancy.