Properties and functions of hormones

hormone(from the Greek participle “ὁρμῶ”, “to set in motion, urge on”) is any member of a class of signaling molecules produced by glands in multi cellular organisms that are transported by the circulatory system to target distant organs to regulate physiology and behaviour.

A) Properties

  • Regarded as “chemical messengers” of the body. They carry the message from the site of synthesis to the target organ.
  • Synthesized by ductless glands called endocrine glands.
  • Effective in extremely small amount which produces a marked effect.
  • Travel in blood to all parts of the body.
  • Affect only particular cells called target cells.
  • May be amino acid derivatives, peptides, proteins or steroids in nature chemically.
  • Have low molecular weight and can diffuse through the cell membranes.
  • Serious physiological disorders may result in excess and deficiency.
  • Have wide spread effects though some may have specific functions.
  • Cannot be stored in the body as they are rapidly altered or destroyed immediately after they have acted on the target organ.

What are Hormones?

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B) Functions

  • Control the general metabolism of the body.
  • Regulate the growth of the organism, moulting, metamorphosis, regeneration and diapause of some animals.
  • Control the gametogenesis, development of secondary sexual characters, oviposition, implantation of the fertilized eggs, development of the embryo in the uterus and child birth.
  • Control the internal environment of the body including regulation of temperature, water and ionic balance of the body, blood sugar levels, etc.
  • Make adaptations to external factors including visual adaptation to light intensities and control of physiological color changes.

Endocrine Function - an overview | ScienceDirect Topics

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Properties and functions of hormones