Hypothalamus

The endocrine system in our body is made of several types of glands that secrete chemical messengers called hormones. These hormones circulate and transmit information from a group of cells to another, or between tissues and organs.

The most important glands that comprise the endocrine system include the thyroid, pituitary, the adrenals and the hypothalamus glands. The hypothalamus hormones directly control and regulate a wide variety of bodily processes. 

What is Hypothalamus?

The hypothalamus is a tiny gland located towards the base of the brain and lies above the pituitary gland. The function of hypothalamus in the brain is a vital one; it forms a direct link between the endocrine system and the nervous system through the pituitary gland.

Structure of Hypothalamus

The hypothalamus has a somewhat complex structure and comprises three regions. Each of these is made up of different kinds of nuclei. These nuclei are groups of nerve cells or neurons that carry out many important functions, such as secreting hormones.

The Parts of Hypothalamus are:

  1. The anterior region

  2. The middle region

  3. The posterior region

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Figure 1: Hypothalamus Location in Brain

Anterior Region

The anterior region is also known as the supraoptic region. The supraoptic part is made of the supraoptic and paraventricular nuclei. These nuclei mostly secrete hormones that interact with the pituitary gland to form more hormones.

The anterior region secretes some essential hypothalamus hormones. These are:

1. Vasopressin

Vasopressin is also known as the antidiuretic hormone or ADH. It modulates the levels of water in the body.

2. Oxytocin

The hormone oxytocin regulates several emotional responses and behaviour such as recognition, sexual arousal, excitement and trust. It also controls some parts of the reproductive system, such as lactation and childbirth.

3. Thyrotropin-releasing Hormone (TRH)

The TRH signals the pituitary gland to secrete thyroid-stimulating hormone or TSH. 

4. Corticotropin-releasing Hormone

The CRH stimulates the pituitary to secrete the adrenocorticotropic hormone or the ACTH. The ACTH signals the secretion of stress hormone which is known as cortisol.

5. Somatostatin

Somatostatin stops the pituitary gland from secreting some specific hormones.

6. Gonadotropin-releasing Hormone (GnRH)

GnRH causes the pituitary to secrete reproductive hormones like FSH and LH.

The anterior region also helps maintain the body’s circadian rhythms and body temperature.

Now, let us recapitulate a few concepts with the following exercise.

Pop Quiz 1

1. Where is the Hypothalamus Located?

a. base of the brain and below pituitary gland

b. top of the brain and above pituitary gland

c. base of the brain and above pituitary gland

d. top of the brain and below pituitary gland

Middle Region

Also known as the tuberal region, this middle region of the hypothalamus is mostly made up of the ventromedial and arcuate nuclei. The ventromedial nucleus helps to regulate appetite, and the arcuate plays a role in secreting GHRH or the growth hormone-releasing hormone. It is responsible for the proper growth and development of a body.

Posterior Region

Known as the mammillary region, the posterior region consists of the posterior hypothalamic nucleus and the mammillary nucleus. It helps control and stabilize body temperature and is also believed to play a role in memory and cognition.

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Figure 2: Hypothalamus Structure

Now we know all about the structure of this hypothalamus. Let us revise our concepts with the following quiz.

Pop Quiz 2

1. Which of these are Hormones Secreted by Hypothalamus?

  1. Oxytocin

  2. Thyrotropin-releasing hormone (TRH)

  3. Corticotropin-releasing hormone

  4. All of these above

Functions of Hypothalamus

Besides the hypothalamus hormones, the hypothalamus also features osmotic sensors that react to concentrations of chloride, carbon dioxide, potassium and sodium. These osmotic sensors signal the kidneys to store or release water depending on their respective levels. The role of hypothalamus is an essential one and includes these following activities: 

  1. Maintaining sleep cycles

  2. Maintaining homeostasis

  3. Connects the nervous and endocrine systems

  4. Balances body fluids

  5. Regulates blood pressure and heart rate

Besides these, the hypothalamus secretes hormones that are involved in many other functions such as appetite and thirst control. Optimum levels of hormones in the bloodstream are necessary for the body to function properly. Low or high levels of a particular hormone could lead to hypothalamus disorders. These include:

  1. Insomnia

  2. Frequent urination

  3. Infertility

  4. Fluctuations in appetite and thirst

  5. Unusually high or low blood pressure

  6. Diabetes insipidus

It is important to eat a balanced diet and ensure that the hypothalamus is healthy and functional.

For more on the work of hypothalamus and other glands in the endocrine system, refer to our PDF notes and solved question papers. Install the Vedantu app today and discover an exciting world of learning with easy access to study materials and online interactive sessions.

FAQ (Frequently Asked Questions)

1. What is the Hypothalamus?

Ans. The hypothalamus is a tiny gland located towards the base of the brain and lies above the pituitary gland. It forms a direct link between the endocrine system and the nervous system through this pituitary gland.

2. The Antidiuretic Hormone is Secreted by which Gland?

Ans. The anterior part of the hypothalamus releases the ADH. 

3. What is the Function of the Hypothalamus?

Ans. The functions of the hypothalamus include quite a few activities like maintaining sleep cycles, maintaining homeostasis, connecting the nervous and endocrine systems, balancing body fluids, regulating blood pressure and heart rate, etc.