Effect of Endocrine System on Human Behaviour

Nervous system protects our body from various dangers by following a sequence of interpretation and reaction to the stimuli.

Endocrine system secretes chemicals called hormones throughout our body which influence our feelings, moods and behaviour.

Endocrine system is composed of glands which is a group of cells that secrete hormones.

Various glands perform various functions related to maintenance and growth of human body by secreting hormones. Glands can be categorized into 2 types:

1. Duct or Exocrine Glands: These glands carry the chemical components to the different body parts with the help of ducts or tubes. Example of this could be tear glands.
2. Ductless or Endocrine Glands: These glands directly secrete the chemical substances called hormones into the bloodstream which is further carried to different body organs and tissues. Hormones stimulate body growth and influence our metabolic process.

Endocrine glands play an important role in ensuring normal behaviour by modulating and influencing the other activities. Various kinds of endocrine glands are the hypothalamus, the pineal gland, the thyroid, the testes, the ovaries and the pituitary gland.

Each gland has its unique function to perform and affect the functioning of the human body and behaviour differently. The hypothalamus connects the endocrine system with the nervous system, which is located at the base of the brain. The hypothalamus comprises of a collection of nuclei which controls human behaviour by a significant extent.

The basic needs such as hunger, sleep, thirst, sex and stress as well as emotional responses are regulated by the hypothalamus. The hypothalamus equally controls the functioning of the pituitary glands, which then regulates the hormonal secretion from other glands into the endocrine system.

The functioning of the endocrine system is controlled by the central nervous system and basically the endocrine system work towards maintaining homeostasis or a chemical equilibrium bodily.

Chemical disequilibrium can result because of the over activity or below optimum functioning of any of the endocrine glands, which may lead to both physiological and psychological abnormalities.

Endocrine glands may be subdivided into the categories of minor and major glands.

Major Endocrine Glands

The Pituitary Gland: This gland is also regarded as the master gland and this small gland is situated near the centre of the brain. The pituitary gland is responsible for regulating both behavioural aspects and also the body growth.

This gland regulates the functioning of the other glands in the body and secretes the hormone called pitutrin. The hormones secreted by the pituitary glands influence the testes and ovaries in making of sex hormones and equally control the menstrual cycle and ovulation process in women.

The Pineal Gland: This gland is situated in the middle of the brain and it secretes melatonin hormone which is responsible for controlling the sleep and waking up cycle.

The Thyroid Gland: The thyroid gland secretes thyroxin which influences the metabolic rate and the growth & development of the body.

Deficiency of thyroid in infants may cause feeblemindedness or cretinism. Poor quality thyroxin may cause gland enlargement or goitre. Deficiency of thyroid in adults may lead to a condition called myxedema or being overweight. Excess secretion of thyroid can cause Grave’s disease.

The Parathyroids: The parathyroids are accountable for the bony framework of the body by regulating the phosphorous and calcium metabolism. Destruction of parathyroid will result in a condition called tetany which is characterized by excited nervous system.

The Adrenal Glands: The adrenal glands regulate the psychological and physiological functioning of the body. The adrenal gland secretes adrenalin or epinephrine and noradrenalin or norepinephrine which regulates the body changes which occur during situations of emergencies or emotional outbursts.

Steroids secreted by the adrenal cortex influence the body metabolism, activity level, reaction to stressful situations and development of secondary sexual characteristics. Deficiency of steroids may cause Addison’s disease and its symptoms could be appetite loss, increase in the fatigue level, irritability, anaemia, weakness, restlessness and skin darkening. An excess secretion of steroids can cause Gushing’s syndrome. This is characterised by decrease in the sex drive, fatigue, muscle weakening feeling and other bodily changes.

Its Hyper secretion in males may lead to feminism and hyper secretion of corticoids in females may result in virilism. Hyper secretion of steroids in a child may result in early sexual maturity or a condition called ‘puberty praecox’.

Gonads: Gonads play a crucial role in sexual development and also reproduction. The male gonads are called testes which secrete the male hormones called testosterone. Testosterone regulates the sexual development, sexual characteristics, physical appearance related changes, drive for sex and sexual behaviour in males in males and equally influences the psychological well-being.

A dysfunction of the gonads may lead to serious psychological issues.

The female sex glands or the ovaries, secrete the female hormones estrogen and progesterone.

Estrogen influences the development of the female sexual organs, sexual characteristics, behavioural changes, drive and motivation for sex. Estrogen and progesterone regulate the menstrual cycle and involved in the conception period.

Research conducted by Dabbs, Hargrove, and Heusel (1996) on the role of the sex hormones in influencing social behaviour show strong evidence between testosterone and aggressive or unruly behaviour. They found that people having high testosterone levels were more unruly and wild, while those who had relatively low levels of testosterone were relatively well behaved, academically strong, well behaved and had pleasant mannerisms.

Banks and Dabbs (1996), highlighted in their research that juvenile prisoners who had relatively high levels of testosterone behaved in a more violent manner.

Tremblay et al. (1998) equally highlighted through his research that testosterone was related to leadership behaviour and mental toughness in young adolescent males.

Research evidences equally prove that the correlation between high testosterone and aggression may not be restricted to males only, but studies show a positive relationship between aggression, competitiveness and testosterone in women also (Cashdan, 2003).