Just as the nervous system sends information around the body via electrical impulses, the endocrine system provides another messaging service that has complete control of your body
If you’ve ever wondered why you never seem to get any taller while your friends are regularly growing out of their clothes, why your skin always breaks out in spots when you want to look your best and why you’re always hungry no matter how much you eat, you need look no further than your hormones. But what exactly are hormones, and why do they seem intent on interfering in your life?
In simple terms, hormones are chemical molecules that act like an internal postal service. These specialised proteins carry vital messages around the body via the bloodstream – thanks to the circulatory system and a strong, beating heart – to their target cells, where they give out clear instructions. Different types of hormones will give instructions to entirely different organs and tissues within the body. This ingenious system begins before your birth and continues to make appropriate changes to your body throughout your entire life, allowing you to develop, grow, thrive and survive.
The endocrine system plays an important role in the transition from foetus to independent newborn baby. Endocrine cells have started to disperse within a few weeks of gestation, and by 13 weeks have developed a hypothalamus and a pituitary gland. The foetus takes hormones from the parent and the placenta acts as a temporary endocrine organ, sharing nutrients and messages between the two. This is expelled as the baby is pushed out. The hormones help the foetus to develop and grow in utero, giving it the best chance to survive the birthing process. As soon as the baby is born, the endocrine system controls every aspect of its life, from growth and strength to temperature and mood. However, it’s when reaching puberty – usually around the≈age of 12 – that most people become aware of the importance of hormones.
It’s during puberty that our bodies develop into their peak physical state and complete sexual maturity. The endocrine system instigates some dramatic bodily changes that can be very confusing and frightening for any unprepared teenager. As adolescence begins, the hypothalamus and pituitary gland stimulate the gonads (ovaries or testes) to produce a variety of hormones that prompt new sexual characteristics. Oestrogen and progesterone increase in girls, causing the breasts to enlarge and the menstrual cycle to begin. Meanwhile, an increase in testosterone in boys initiates a deepening of the voice, enlargement of the sexual organs and an increase
