Endocrine System

Types of Hormones

Topic Menu
Content Contributors
Christian Bien Portrait_edited.jpg

Ben Whitten

Learning Objectives

tutorial.png

one.png
What is a hormone?
Slide1.jpeg

A hormone is a chemical substance secreted by specialised cells located in an endocrine gland, and into the blood which binds to receptors found on or in target cells, acting to change the activity of the cell. 


Hormones circulate through the bloodstream and are specific. This means that they are only able to influence cells that have the correct receptor for that hormone. If all receptor molecules are occupied by hormone molecules, saturation occurs; this means that any additional hormone secretions will not produce a greater effect.

two.png
What are the two types of hormones?
Slide2.jpeg

Image: Ben Whitten (Head of Education)


  • Protein/amine hormones

  • Steroid hormones


Protein/amine hormones 

Water-soluble and cannot pass through the cell membrane. These types of hormones work by attaching to receptor molecules found on the cell membrane of a target cell. The formation of a hormone-receptor complex causes a secondary messenger substance to diffuse through the cell and activate a particular enzyme; these hormones cause a response rapidly but are short-lasting.


Steroid hormones 

Lipid-soluble and can pass through the cell membrane. These types of hormones enter a target cell by diffusion through the cell membrane and combining with a receptor protein in the cytoplasm, forming a hormone-receptor complex. The hormone-receptor complex then enters the nucleus, altering gene expression (protein synthesis). These hormones are slow in their effect, but longer-lasting.

two.png
How do hormones change cell activity?
Slide2.jpeg

Hormones change the functioning of cells via changing the quantity, type or activities of proteins (including enzymes). Hormones may do any of the following:


  • Activate genes in the nucleus to produce a particular structural protein or enzyme (turning genes on)

  • Alter the shape or structure of an enzyme so that it’s turned on/off

  • Alter the rate of production of an enzyme or structural protein

two.png
What are synthetic hormones?
Slide2.jpeg

Some hormones are produced artificially in a laboratory, named synthetic hormones. hormones are those produced artificially in a lab. They can produce side effects which natural hormones do not produce, as they may have a slightly different molecular structure and the body may react to these differences. 


For example, levothyroxine is a synthetic hormone to treat hypothyroidism (underactive thyroid meaning low thyroxine levels).

two.png
Slide2.jpeg
two.png
Slide2.jpeg
two.png
Slide2.jpeg
two.png
Slide2.jpeg
Endocrine System
Types of Hormones
Enzyme Amplification and Hormone Clearance
The Hypothalamus and Pituitary Gland
Pituitary Gland Hormones
Other Endocrine Glands
Students Walking Up Stairs_edited.jpg

Registrations Now Open for Empowered Academy

A Free Student-Centred Revision Program

Logo-New-Large.png