Question

What are hormones and Classification of hormones?

Answer 1

Hormones are the chemical messengers which are produced from endocrine glands and reach their target organ through blood to perform an specific function (mainly stimulation).

Explanation:

Hormones can be classified in three ways.

i) Structural Classification:-

a)Steroid Hormones:- Derived from Cholesterol. The Hormones produced in Adrenal Cortex and The Sex Hormones. They have important functions in the body like water balance, sexual development, stress response etc.

E.g. :- Testosterone, Progesterone, Glucocorticosteriods, Mineralocorticosteroids etc.

b)Amino acid Derivative Hormones:- Derived from Amino acids and Peptides.

`diamond` Thyroid Hormones:- Derived from the Amino acid Tyrosine, Contains Iodine Element. E.g. Tetra-iodothyronine (`T_4`), Tri-iodothyronine (`T_3`), Parathormone, Calcitonin etc.

`diamond` Catecholamines:- Derived from Tyrosine, can also function as a neurotransmitter. E.g. Epineprhine (Adrenaline), Nor-epinephrine(Nor-adrenaline) etc.

`diamond` Tryptophan-based Hormones:- As the name suggests, derived from the Essential Amino acid Tryptophan.
E.g. Melatonin, Serotonin.

`diamond` Glutamic acid-based Hormones:- Histamine is an example.

c)Fatty acid Derivative Hormones or Eicosaniods:- Most abundant precursor is the Essential Fatty Acid Arachidonic Acid. E.g. Prostaglandins (Kidney), Prostacyclins, Leukotrienes, Thromboxanes etc.

ii)Classification by Solubility:-

a) Lipid-soluble Hormones:- Soluble in Lipids, Can work on the cell directly by going through the bi-layer phospolipid membrane of cells. E.g. Steroid Hormones.

b)Water-soluble Hormones:- Soluble in Water. Has to work indirectly because of the lack of penetration through the cell membrane. E.g. Amino acid-based Hormones.

iii) Classification by Target:-

a) Tropic Hormones:- Tropic Hormones are hormones which stimulate other endocrine glands to work. Generally Released from Pituitary Glands.

E.g. Gonado-Tropic Hormones, Thyroid Stimulating Hormone, Somatotropic Hormone, Adreno-Cortico Tropic Hormones etc.

b) Non-Tropic Hormones:- These work on other cells except Endocrine Glands. E.g. Calcitonin, Adrenaline, Oxytocin, Insulin, Glucagon etc.

Here it is. Hope this Helps.

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