Hormones (Chemical nature of Hormones).pptx

*History
*Properties of Hormones
*Types of Hormones
1. Steroid hormones
2. Nonsteroid hormones
i) Amino Acid-derived hormones
ii) Peptide hormones
iii) Protein hormones
iv) Glycoprotein hormones
*Functions of Hormones

1. Hormones CHEMICAL NATURE OF HORMONES

2. History: A chemical substance produced in the body that controls and regulates the activity of certain cells or organs. The first hormone was discovered by the English physiologist William M. Bayliss and Ernest H. Starling in 1903 . They discovered secretin hormone which is secreted by intestinal mucosa and stimulating the secretion of pancreatic juice. The term ‘hormone ’ was introduced by Starling in 1905.

3. Properties of hormones Hormones are produced by a specialized glands and are secreted directly into the blood stream . Hormones exert their effects not where they are locally produced, but on other tissues of the body . Hormones have low molecular weight so hormones can easily pass out through the capillaries. Whenever their function is over, hormones are readily destroyed or inactivated or excreted. Hormones always act in very low concentration .

4. Types of hormones There are two types of hormones Steroid hormones Nonsteroid hormones Non steroid hormones are further classified into following groups. Amino acid-derived h ormones Peptide hormones Protein hormones Glycoprotein hormones

5. Steroid Hormones These are made up of lipids which are basically derived from cholesterol . Example: Testosterone, Estrogen, Progesterone

6. Amino Acid-Derived Hormones They are relatively small molecules derived from the amino acids tyrosine and tryptophan . Examples: epinephrine, norepinephrine, melatonin

7. Peptide Hormones These hormones are made up of few amino acids and present as linear chain . Examples include oxytocin and vasopressin which are made up of only nine amino acids. Chemical structure of Oxytocin

8. Protein Hormones These hormones are made up of protein with many amino acids and have the primary , secondary and tertiary configuration . Example: Insulin, Glucagon, Growth Hormone Insulin Structure Growth Hormone

9. Glycoprotein Hormones These hormones are glycoprotein in nature which is a conjugated protein made up of carbohydrate and protein . Examples: LH,TSH,FSH

10. Difference Between Hormone and Enzyme

11. Functions of Hormones Metabolism: To regulate energy production, stabilize the metabolic rate. Homeostasis   : Internal environmental factors including temperature regulation, water and ion balance, blood glucose levels, etc. are maintained by hormones. Growth, maturation and regeneration  : Hormones control growth by addition of segments. Hormones also control maturation and regeneration in different organisms.

12. Secondary sexual characters and reproductive activities  : Hormones secreted by gonads produce secondary sexual characters and reproductive activities. For example, testosterone in male produces male characters and maturation of sperms. The progesterone controls female secondary sexual characters, maturation of ovum, implantation of fertilized egg, its retention in the uterus and relaxin control the child birth . Control of other endocrine glands  : In some cases hormones secreted by one gland controls the secretary activity of other endocrine glands. For example, trophic hormones of anterior pituitary control the secretion of thyroid, adrenal cortex, gonads, etc .