Different Hormones and Their Functions- Endocrine System

The Love Hormone

Hormones are the chemical messengers of the body. They regulate the body physiology based on the signals from brain. They transfer the signal directly on to the respective organ or system for the changes to happen. So they are like the messengers carrying message from the brain to the other organs.

They are produced by the secretory cells of specific glands. These glands are of different types which synthesize and secrete the concerned hormone. But they do not release them into the blood. Instead the blood flows through these glands and carry away.

So they are termed as endocrine glands. Most of the hormones are named after the gland from which they are secreted.These are then carried by blood into target tissues where they show their effect.

• They regulate most of the body physiology and functions.
• They bring such changes by acting at the level of genetic material or proteList of hormonesin formation machinery of the cell.
• These hormones if deficient or if excess can lead to hormonal disorders.
• These can have deleterious effect on the health and physiology.

So how many hormones are there in the human body? Below is the comprehensive list with their functions.

Endocrine gland	Hormone	Main tissues acted on by hormone	Main function of hormones
Hypothalamus	Thyrotrophin releasing hormone (TRH)	Anterior pituitary	Stimulates release of thyroid stimulating hormone (TSH) from the anterior pituitary
	Somatostatin	Anterior pituitary	Inhibitory hormone that prevents release of hormones such as growth hormone from the anterior pituitary
	Gonadotrophin releasing hormone (GnRH)	Anterior pituitary	Stimulates release of follicle stimulating hormone (FSH) and luteinising hormone (LH) from the anterior pituitary
	Corticotrophin releasing hormone (CRH)	Anterior pituitary	Stimulates adrenocorticotrophic hormone (ACTH) release from the anterior pituitary
	Growth Hormone Releasing Hormone (GHRH)	Anterior pituitary	Stimulates release of growth hormone (GH) form the anterior pituitary
Anterior pituitary	Thyroid stimulating hormone (TSH)	Thyroid gland	Stimulates release of thyroxine and tri-iodothyronine from the thyroid gland
	Luteinising hormone (LH)	Ovary/Testis	Females: promotes ovulation of the egg and stimulates oestrogen and progesterone production Males: promotes testosterone release from the testis
	Follicle stimulating hormone (FSH)	Ovary/Testis	Females: promotes development of eggs and follicles in the ovary prior to ovulationMales: promotes production of testosterone from testis
	Growth Hormone (GH)	Bones, cartilage, muscle, fat, liver, heart	Acts to promote growth of bones and organs
	Prolactin (PRL)	Breasts, brain	Stimulates milk production in the breasts and plays a role in sexual behaviour
	Adrenocortico-trophic hormone (ACTH)	Adrenal glands	Stimulates the adrenal glands to produce mainly cortisol
Posterior pituitary	Vasopressin (anti-diuretic hormone, ADH)	Kidney, blood vessels, blood components	Acts to maintain blood pressure by causing the kidney to retain fluid and by constricting blood vessels
	Oxytocin	Uterus, milk ducts of breasts	Causes ejection of milk from the milk ducts and causes constriction of the uterus during labour
Thyroid gland	Thyroxine (T4)	Most tissues	Acts to regulate the body’s metabolic rate
	Tri-iodothyronine (T3)	Most tissues	Acts to regulate the body’s metabolic rate
Parathyroid glands	Parathyroid hormone (PTH)	Kidney, Bone cells	Increases blood calcium levels in the blood when they are low
	Calcitonin	Kidney, Bone cells	Decreases blood calcium levels when they are high
Adrenal cortex	Cortisol	Most tissues	Involved in a huge array of physiological functions including blood pressure regulation, immune system functioning and blood glucose regulation
	Aldosterone	Kidney	Acts to maintain blood pressure by causing salt and water retention
	Androgens	Most tissues	Steroid hormones that promote development of male characteristics. Physiological function unclear
Adrenal medulla	Adrenaline and noradrenaline (the catecholamines)	Most tissues	Involved in many physiological systems including blood pressure regulation, gastrointestinal movement and patency of the airways
Pancreas	Insulin	Muscle, fat tissue	Acts to lower blood glucose levels
	Glucagon	Liver	Acts to raise blood glucose levels
	Somatostatin	Pancreas	Acts to inhibit glucagon and insulin release
Ovary	Oestrogens	Breast, Uterus, Internal and external genitalia	Acts to promote development of female primary and secondary sexual characteristics. Important role in preparing the uterus for implantation of embryo
	Progesterone	BreastUterus	Affects female sexual characteristics and important in the maintenance of pregnancy
Testis	Testosterone	Sexual organs	Promotes the development of male sexual characteristics including sperm development
Stomach	Gastrin	Stomach	Promotes acid secretion in the stomach
	Serotonin (5-HT)	Stomach	Causes constriction of the stomach muscles
Duodenum and jejunum	Secretin	Stomach, Liver	Inhibits secretions from the stomach and increases bile production
	Cholecystokinin (CCK)	Liver, Pancreas	Stimulates release of bile from the gall bladder and causes the pancreas to release digestive enzymes
Kidney	Erythropoietin	Bone marrow	Stimulates red blood cell development in the bone marrow
Heart	Atrial natiuretic factor (ANF)	Kidney	Lowers blood pressure by promoting salt and water loss
Skin	Vitamin D	Small intestine, Kidney, Bone cells	Stimulates the uptake of calcium in the small intestine, retention of calcium and release of calcium from bone stores

From the above list, the ones secreted by hypothalamus, anterior and posterior pituitary are formed in brain.
While rest are formed outside the brain. Once released they are carried on by blood to different regions.
The hormones on reaching the corresponding regions elicit their response.
It is quite interesting to see that the ones released from they also brain regulate the secretion of other hormones.
So it indicates that their secretion is controlled by brain and indirectly all the other hormones too. Thus the whole body physiology seems to be under the control of brain.
Any emotional disturbance to the brain can lead to alteration in secretion of these hormones. Thus we can see that during emotional changes we experience hormonal imbalance too.