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Functions of the Hypothalamus

Shashank Nakate
The hypothalamus is one of the most important part of the brain. The hypothalamus functions provide us with an overview of the different aspects of the working of hypothalamus.
The hypothalamus is an almond-shaped organ of the brain that lies just below the thalamus and slightly above the brain stem. This part of the brain does the job of connecting the endocrine system with the nervous system through the pituitary gland. The hypothalamus gland is present in the ventral position to the diencephalon.

Functions of the Hypothalamus
The hypothalamus is one of the important organs of the brain that plays a crucial role in its functioning. It receives stimuli from the external environment i.e. the visceral or somatic sense organs. Receptors of the hypothalamus help in capturing the stimuli. Before reaching the hypothalamus, the stimuli must travel through the medulla oblongata.
The most important function of hypothalamus is homeostasis. Maintenance of equilibrium of different bodily systems, which in most cases, don't waiver from a fixed, set-point is known as homeostasis.
The different factors which play an important role in regulating the process of homeostasis are body temperature, blood pressure, electrolyte balance, fluid balance and body weight.
Temperature is regulated by the anterior (responsible for cooling) and posterior (responsible for heating) parts of the hypothalamus. As the temperature of arterial blood rises, thermoreceptors (sensitive to heat) present in the posterior hypothalamus get activated.
The autonomous nervous system responds(ANS) by means of sweating and cutaneous vasodilation. These responses cause the body temperature to lower.
When body temperature goes down, thermoreceptors sensitive to low temperature (present in anterior hypothalamus) get activated. Responses initiated by the ANS following the lowering of body temperature include shivering, increased heart rate, cutaneous vasoconstriction, mobilization of carbohydrate reserve and the elevation of basal metabolic rate.
Supraoptic and paraventricular nuclei maintain the water-balance in our body.

As the water level in the body decreases, salt concentration in blood increases. This is detected by osmoreceptors in hypothalamus, which in turn release vasopressin in neurohypophysis capillaries.
Vasopressin helps retain water in the kidney, thereby reducing the salt concentration.

When the water level in the body rises, the vasopressin secreted in the capillaries of neurohypophysis is inhibited. In the absence of vasopressin, the available amount of water is absorbed by kidneys in order to form urine.
This process causes the level of water in the body to drop down; thus, the salt concentration increases.

The regulation of endocrine hormonal levels, body metabolism, sensory processing are all regulated by the hypothalamus.
This was a broad overview of the different functions of hypothalamus. Let us understand more about the specific functions of this part of the brain.
The autonomic nervous system is governed by the hypothalamus; this includes the process of controlling the autonomic as well as subconscious functions of the nervous system.
By secreting certain chemicals to the front lobe of the pituitary gland, their output is controlled.
The hypothalamus which governs the endocrine system plays an important role in controlling our emotional behavior.
Maintaining the balance of circadian rhythms also is one of the important functions of hypothalamus. In the anterior hypothalamus, there lies the suprachiasmatic nucleus. It helps in setting the body's biological clock. The retinohypothalamic tract provides information about the daytime or nighttime to the suprachiasmatic nucleus.

Lateral Hypothalamus Function

This part of the hypothalamus is associated with hunger. If the lateral hypothalamus is stimulated, one starts feeling hungry. Any damage caused to the lateral hypothalamus is responsible for the reduction in food intake.
When the sugar levels in the blood drop down, the hypothalamus receives a message through glucostatic receptors. On receiving this message, certain specific neurons of the brain get stimulated; the overall effect of this whole process is that one feels hungry.
The function of ventromedial hypothalamus is similar to that of lateral hypothalamus. When a person has just eaten or is eating, the glucose level in the blood starts increasing. Glucostatic receptors take this message to ventromedial hypothalamus. Upon receiving the message from the glucostatic receptors, one gets a feeling of fullness.
The smooth working of many of our bodily systems is dependent on the proper functioning of hypothalamus. The details presented here give a rough idea of the functioning of this tiny, but important part of the brain.