Hormone


•
Hormone = an organic chemical compound produced by an endocrine gland & is transported by blood to its target organ to obtain a certain response. 
An endocrine gland is a ductless gland. 
To synthesise & secrete hormones. 
The hormones are secreted into the blood stream à reach all parts of the body.à only certain organ will respond (target organ of the hormone)
•Both nervous system & endocrine system are involved in the coordination of body functions.
Nervous system – detecting changes in the external environment & obtains relatively quick responses.
Some physiological activities occur over a long period of time (menstrual cycle, development of secondary sexual characteristics & growth) à cannot be regulated by nervous system. 
•It is necessary to have an endocrine system to regulate them. The ES complements the NS in coordinating body activities.


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