The Control and co- ordination is carried out by the nervous system and the endocrine system which are integrated and considered as neuro – endocrine system.
The endocrine glands are special type of glands. These are
the glands of internal secretion and do not have duct system and release their
secretions directly into the blood stream; therefore known as ductless glands.
The endocrine glands secrete the special chemical messengers
called hormones. They are carried by the blood stream to influence the
functioning of specific “target” organs or tissues of the body as a whole. The
regulatory role may be either excitation or inhibition. The word “hormone” (G.
hormaein = to excite) is therefore misnomer.
Common
Properties of Hormones :
1.Hormones are produced in response to specific stimulus.
2. The rate of secretion varies from low to very high
depending on nature and intensity of the stimulus.
3. They are produced in one organ and show their effect on
distant “target” organ.
4. Hormones are carried through blood.
5. Hormones are bound to specific carrier proteins while
being transported in the blood.
6. Hormones have a high degree of target specificity.
7. Every hormone acts basically by modifying some aspect of
cellular metabolism.
8. The excessive secretions or deficiencies of hormones may
lead to serious disorders.
The main endocrine glands in human body are :
i)Pituitary- hypothalamus
ii) Thyroid and parathyroid glands
iii) Adrenal glands
iv) Islets of Langerhans in pancreas
v) Endocrine part of gonads i.e. Testes and Ovary.