What Is a Hormone?

Animals have two types of hormones namely the exocrine and the endocrine hormones. The exocrine hormones are first secreted into a duct before flowing into the blood system. On the other hand; the endocrine hormones directly enter the bloodstream after secretion.

What are the effects of hormones in the body?

Hormones have the following effects in our bodies:

* They are useful in the psychological preparation for fighting, mating fleeing and other activities.

* Physical changes and development during various stages of life e.g puberty and menopause.

* Inhibition or stimulation of growth.

* Activation of the inhibition of the immune system.

* Change of moods.

* Regulation of the metabolism rate.

* Sexual arousal.

* Control of the reproductive cycle.

In general, hormones play many vital roles in our bodies.

Different Classes of Hormones

We have three classes of vertebrate hormones. These are:

* The peptide hormones (made up of a chain of amino acids).

* Lipid hormones (derived from lipids and phospholipids.

* Monoamines (derived from the phenylalanine, tryptophan and tyrosine.

Important Hormones and Their roles in our Bodies

As we’ve already seen, hormones play very vital roles in the human body. Let us now have a look at some of the most important human hormones and the specific roles that they perform.


This hormone is secreted from the outer adrenal cortex by the adrenal gland. It plays a key role by promoting the re-absorption of sodium in the kidneys, increasing water retention in the body and promoting increase in blood volume.

Anti-diuretic Hormone

Also known as the ADH, this hormone originates from the pituitary gland. It helps in the vasoconstriction and water retention in the kidneys.

Cholecystokinin (CCK)

Cholecystokinin is secreted in the duodenum. This hormone helps in the production of the digestive hormones, suppression of hunger and drug tolerance. Its main role is to ensure a proper digestion and satisfaction of cravings.

Folicle Stimulating Hormone (FSH)

FSH is secreted in the anterior pituitary gland. It plays a very crucial role in the maturation of the female productive system (the graafian follicles). It is also responsible for some physical changes that occur during puberty.

Growth Hormone

Commonly referred to as GH, this hormone originates from the anterior pituitary. Its main role is to trigger cell production and regeneration. It strengthens the muscles and the bones as one grows. It enhances protein synthesis thus increasing one’s bulk of muscles. Basically, it controls the growth of all the body organs except the brain.


Last but definitely not least is the insulin. This hormone is produced by the beta cells found in the pancreas. Insulin is very vital in maintaining the blood sugar levels. It is also involved in several other metabolic processes.

Just to summarize, the concept of hormones is really wide and detailed. However, I hope that this write-up will provide you with good background knowledge on the same.