Article: Arhama Shams Sheikh | Edited: Atri Das | Illustrations: Roshmija Biswas
Hormones are chemical messengers that are secreted by endocrine glands directly into the bloodstream which is then carried forward to the body organs and muscles to exert their function. Decades of study has revealed that hormones play a major role in determining certain behaviours and traits in individuals. Hormones are produced in the endocrine glands which are secreted into the bloodstream and carried to the effector organs.
Decades of study has revealed that hormones play a major role in determining certain behaviours and traits in individuals. Hormones are produced in the endocrine glands which are secreted into the bloodstream and carried to the effector organs.
The main endocrine glands associated with secretion of hormones that impact human behaviour are:
Thyroid Gland & Parathyroid Gland
I. Pituitary Gland
The pituitary gland is popularly referred to as the “master” gland because it works as a catalyst by controlling the functions of the other endocrine glands in the body. The hypothalamus and the pituitary gland work in tandem with one another where the key role of the hypothalamus is to send signals to the pituitary gland to start or stop secreting certain hormones. Hypothalamus connects the body with the nervous system.
The hormones secreted by the pituitary gland are Follicle Stimulating Hormone (FSH) Luteinizing hormone (LH)
FSH plays an important role in sexual development and functioning. It controls the menstrual cycle in females and stimulates the growth of eggs in the ovaries. In men it controls the production of sperm.
LH controls the functions of gonads. It is responsible for the production of estrogen in females and testosterone in males.
Both the FSH and LH work together to ensure normal functioning of the gonads. Over secretion causes polycystic ovary syndrome (PCOS) in females which affect the function of the ovaries. It can make women overly conscious in regard to their own self and can significantly reduce their self-esteem.
This hormone is produced by the hypothalamus and secreted by the pituitary gland. Oxytocin, also known as the “love” hormone generates feelings of pleasantness and joy in social bonding situations. It plays a role in pro-social behaviour, sexual reproduction and post childbirth. Research on human and animal studies reveal that due to the high levels of
oxytocin in mothers, they are more likely to engage in affectionate parenting styles such as holding the infant in a warm and gentle manner, speaking or lulling them to sleep in a certain way and checking on the baby a number of times.
Adrenocorticotropic Hormone (ACTH)
Stimulates the adrenal glands to secrete epinephrine, norepinephrine and cortisol which is released by the anterior pituitary. It is majorly responsible for maintaining the circadian rhythm.
II. Thyroid Gland
This gland secretes thyroxine which controls body metabolism and body weight. It controls mood and behaviour to a certain extent. Under secretion of this hormone makes people lethargic, sleepy, and gloomy. From the point of view of mental disorders, it may lead to depression. Many a times depressed individuals may show increased signs of eating behaviour that may lead to obesity. The degree of behaviour varies – some people may become sluggish, some may not.
These are four pea shaped structure near the thyroid gland. They regulate calcium level within the blood. Parathyroids also control the amount of blood in the bones and how strong and dense the bones are. Too much of calcium in the blood makes an individual sluggish and less excitable. On the other hand, below average calcium levels make a person less excited, restless, irritable. This occurs because of a potential tension that builds up in the nervous cells. Some studies, although very few in number, suggest that such individuals may go on to become anti-socials. (Crime and the endocrine glands, L Berman - American Journal of Psychiatry, 1932 - American Psychiatric Association)
III. Adrenal Glands
These are the emergency glands. They are activated when a person encounters a dangerous and stressful situation which causes the infamous flight or fight response. The adrenal glands secrete the following three major stress hormones:
Epinephrine and Norepinephrine
These are released in the wake of perception of a dangerous situation. The amygdala signals the hypothalamus to activate the autonomic nervous system which triggers the adrenal gland to start releasing epinephrine into the bloodstream. This surge is referred to as the “fight or flight” response where an individual experience a rush of adrenaline throughout their body. It leads to physiological changes in the body such as increased heart rate, increased blood sugar level, faster breathing and the like. Norepinephrine performs similar functions such as constriction of blood vessels and increased blood pressure. The primary role of norepinephrine is to initiate a state of arousal in the body.
It helps maintain fluid balance and blood pressure in the body. Cortisol maintains blood sugar levels, regulates metabolism and reduces inflammation. Constant secretion of this hormone may prove lethal to the body and may lead to complete exhaustion in the body. It depletes the resources such as white blood cells which act as a protection against foreign bodies. Cortisol is known as the 'stress hormone' as it is released during stressful situations and temporarily shuts down the body's system which is non-essential during an emergency situation like sexual drive and hunger. Too much of cortisol in the blood may prove to be harmful to the body.
This is the largest gland in the human body and lies near the stomach. It is primarily responsible for digestion of food and secretes insulin hormone. It enables the process of breaking down glucose in the blood and to convert into glycogen to be used up by the body. Insulin imbalance may lead to the disease diabetic mellitus.
A gonad is a sex gland that produces the gametes and sex hormones in an organism.
Testes in males produces testosterone. High levels of this hormone are linked with aggression, depression, impulsivity, and mood swings. Low levels are associated with passivity, irritability, anger, insecurity and anxiety. Adolescent boys with below average testosterone production may not experience normal masculinization which may lead to feelings of insecurity about body image.
Ovaries produce estrogen and progesterone in females. Estrogen plays a key role in stimulating serotonin and endorphins which create positive feelings in people. It also causes mood swings in women going through PMS or premenstrual syndrome and postpartum depression. Progesterone creates a calming and soothing effect for maintain hormonal equilibrium.
Both the male and female hormones play a major role in the development of secondary sexual characteristics in adolescents. If their hormones fail to function effectively, their sexual exploration might get hampered which may lead to stress and anxiety.
The endocrine glands are of immense significance in determining different kinds behaviour and emotion that emerge as a result of secretion of these hormones. They serve a major role in influencing the nervous system in regulating a multitude of human behaviours.