Function                                                                                                                                        

Overview of Hypothalamic Nuclei and Summary of Functions

The main function of the hypothalamus is homeostasis. Homeostasis is the maintenance of the internal environment, and is determined at a cellular level.

The hypothalamus is made up of a collection of nuclei that all have more specific roles in relation to homeostatic control.  (A brief summary of their fuction can be seen in the diagram above)

 

Key Roles of the Hypothalamus, including specific homeostatic functions:

  • Maintenance of body temperature
  • Maintenance of water balance
  • Circadian rhythm, which sets the body’s biological clock
  • Regulation of endocrine hormonal levels
  • Appetite
  • Behaviour
  • Milk production

 

The balance of the internal environment is kept in balance by a variety of hormones:

 

The hypothalamic pituitary adrenal axis is extremely important in homeostatic control and is under the influence of various feedback mechanisms. These feedback mechanisms can be positive or negative and as such result in the release or inhibition of various hormones.

 

The table below summarises the hormonal feedback of hypothalamic hormones on pituitary hormones.

Hypothalmic Hormones and their effects on the pituitary gland hormones

Thyrotropin releasing hormone results in the release of Thyroid Stimulating  Hormone and Prolactin

Gonadotropin releasing hormone causes release of the Gonadotropins, LH and FSH.

Growth hormone releasing hormone  leads to the release of Growth Hormone

Somatostatin  results in inhibition of Growth Hormone

Corticotropin releasing hormone causes the release of  Adrenocorticotropic Hormone

Dopamine causes the inhibiton of Prolactin

 

 

The Adrenal Gland, most specifically the adrenal cortex, is also involved in this axis. Glucocorticoids are released from the adrenal cortices most notably Cortisol which is released in response to Adrenocorticotropic hormone.

 

Image courtesy of  http://commons.wikimedia.org/wiki/File:ACTH_Negative_Feedback.svg under the Creative Commons licence.