Diagram of Hypothalamus and Pituitary

The hypothalamus and pituitary together form the central command system of the human brain. The hypothalamus is located at the centre of the brain, and it connects the nervous system and the endocrine system through the pituitary. The pituitary is a lobe-like structure that protrudes from the base of the hypothalamus.

Let’s learn more about the structure of the hypothalamus and pituitary with a diagram.

Table of Contents:

Labelled Diagram of Hypothalamus and Pituitary

Hypothalamus and Pituitary Diagram

Description

  • Hypothalamus is a diencephalic part that is situated below the thalamus in the ventral portion of the diencephalon.
  • The hypothalamus is formed by a bunch of nuclei that can be divided into three groups – anterior or preoptic group nuclei, middle or tuberal group nuclei and posterior or mamillary group.
  • The base of the hypothalamus protrudes into the pituitary gland.
  • The pituitary gland or hypophysis is a small pea-sized endocrine gland with a weight of 0.5 to 1 g and a diameter of about 1 cm. It is situated in a depression present at the base of the skull.
  • It is connected with the hypothalamus by the hypophyseal stalk or the pituitary stalk.
  • The pituitary gland is distinguished into two divisions, namely the adenohypophysis or the anterior pituitary and the neurohypophysis or the posterior pituitary.
  • Between the two divisions, there is a small and relatively avascular structure called pars intermedia which also forms a part of the anterior pituitary.
  • The anterior pituitary consists of three parts, namely the pars distalis, pars tuberalis and the pars intermedia.
  • Hormones from the hypothalamus are transported to the anterior pituitary through hypothalamo-hypophyseal portal blood vessels.
  • The posterior pituitary consists of three parts – the infundibular process or pars nervosa, infundibular stem or neural stalk and the median eminence.
  • The hormones from the hypothalamus to the posterior pituitary are transported by nerve fibres of the hypothalamo-hypophyseal tract.
  • Pars tuberalis of the anterior pituitary and the neural stalk of the posterior pituitary together form the hypophyseal stalk.

Significance

Hypothalamus is the vital part of the brain that deals with the homeostasis of the body. It regulates many important functions of the body like metabolic activities, endocrine functions, hunger, thirst, visceral functions, sexual functions, emotion, sleep, wakefulness, etc. Hypothalamus controls the secretions of anterior pituitary gland by secreting releasing hormones and inhibitory hormones. The anterior pituitary hormones include the growth hormone, thyroid hormone, luteinising hormone, adrenocorticotropic hormone (ACTH), etc. Furthermore, the hypothalamus is the site of synthesis for the posterior pituitary hormones like the oxytocin and antidiuretic hormone (ADH).

Frequently Asked Questions

What is an endocrine system?

Endocrine system is a powerful network of various glands that acts as a messenger system. It comprises feedback loops of hormones and has a great impact on the functioning of other organ systems.

What are the various endocrine glands?

Endocrine glands secrete hormones directly into the bloodstream. The major endocrine glands are – hypothalamus, pituitary, pineal gland, pancreas, adrenal, thyroid, parathyroid and the gonads.

What is homeostasis?

Homeostasis refers to the maintenance of a constant internal environment of the body (homeo = same; stasis = standing). This concept forms the basis of physiology.

Further Reading:

Keep exploring BYJU’S Biology for more exciting topics.

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