Hormones have several effects on the body that are vital to its function. An excess or deficiency in hormones can significantly impact on an individual's normal daily living. Insulin deficiency, for example, leads to a decrease in the body's ability to synthesize and utilize the blood glucose absorbed from food, giving rise to diabetes and its associated complications.
Some of the effects of hormones on bodily functions are detailed below.
Regulating the growth and development of the body. A deficiency in a vital hormone such as growth hormone can lead to severely stunted growth in children and even dwarfism. By contrast, excess growth hormone can lead to acromegaly and gigantism or excessive height. Several other hormones such as thyroid hormones, cortisol, and insulin are also vital in growth and development.
Activation and suppression of the immune system that is primarily mediated by cortisol and steroid hormones.
The development of reproductive functions such as menstruation, pregnancy, lactation and childbirth. These are mediated by the sex hormones estrogen and testosterone. Other important hormones in the reproduction process include oxytocin for child birth, prolactin for lactation and luteinizing hormone (LH) and follicle stimulating hormone (FSH) for maintaining a normal menstrual cycle.
Controlling secretion of other hormones. For example, thyroid stimulating hormone (TSH) released from the pituitary gland stimulates the release of the thyroid hormone thyroxine. The resulting increased level of thyroid hormone in the blood acts as a feedback signal to the pituitary to stop releasing TSH and the hormone therefore self-regulates its secretion. This method of inhibiting a hormone's own release is called feedback inhibition.
Other effects of hormones on bodily functions can include:
- Maintaining salt and water balance
- Mood swings and cognitive functions
- Regulation of metabolic pathways by thyroxine, insulin and cortisol. These hormones aid the absorption and utilization of various nutrients in the body.
- Controlling hunger and thirst
- Controlling programmed cell death or apoptosis