As the nerve fibres do not connected with all the cell of the body so the co-ordination is regulated by hormones.
Gland:- Those structure which secrete any thing is called gland.
-Gland is of three types-
1.Endocrine gland
2.Exocrine gland
3.Heterocrine gland
1.Endocrine gland:-
-Those gland which secrete their secretion directly in to blood or lymph.-Endocrine gland have no duct so called ductless gland.
-The branch dealing with the study of endocrine glands and action of their hormones is called endocrinology.
-Endocrine gland secrete hormone.
2.Exocrine gland:-
-Those gland which secrete their secretion in duct is called exocrine gland.-It is also called duct gland.eg-sweat gland,salivary gland liver etc.
ENZYME:-Enzymes are biological catalysts which increase the rate of a reaction but do not participate in it.
-Enzymes always proteinaceous.
3.Heterocrine gland:-Those gland with partly exocrine with duct and partly endocrine without duct.
-Exocrine part secrete their secretion in duct while endocrine part secrete their secretion directly in blood.eg-pancreas
HORMONE
-Word hormone is originates from a greek word hormaein means to excite.
-Hormones are non-nutrient chemical which acts as intercellular messenger and are produced in traced amount.
Hormones are also called chemical messenger or information molecule.
-First discovered hormone is secretin.
-It was discovered by two English physiologist Baylis & Starling in 1903.
-Term hormone was coined by Starling.
-Hormone are classified in to three classes on the basis of their chemical composition.:-
1.Amine hormone:-Those hormone which is derived from tyrosine amino acid.eg:-Thyroxine, adrenaline,nor-adrenaline.
2.Steriod:-Those fat soluble hormone which are derived from cholesterol.eg:-corticol,aldosterone testosterone, progestrone etc.
3.Proteinous hormone:-Those hormone which is formed by the interlinking of 3-20amino acid by peptide bond and are water soluble.eg:-TSH, FSH, LH, ACTH, insulin, glucagon, ADH ETC.
