The hypothalamus is a tiny gland located towards the base of the brain and lies above the pituitary gland. It is a small organ located in the brain that controls secretions from the pituitary gland which sends hormones to different organs. The hypothalamus is part of the forebrain and is at the base of the thalamus bordered on the sides by temporal lobes and optic tracts. It includes many centers that control not only our body temperature but also our daily activities.
Structure of Hypothalamus
The structure of the hypothalamus is made up of three main regions:
- Anterior Region: The anterior region is also known as the supraoptic region. It regulates body temperature and maintains the circadian rhythm. There are several small nuclei in the hypothalamus. The major nuclei include supraoptic and paraventricular nuclei. The nuclei in this region are involved in hormone secretion.
- Middle Region: This is known as the tuberal region. It consists of ventromedial and arcuate nuclei. The ventromedial nuclei control the appetite, whereas the arcuate nuclei secrete the growth hormone responsible for the growth and development of the body.
- Posterior Region: This region is also known as the mammillary region. The major nuclei include the posterior hypothalamic nucleus and mammillary nuclei. The posterior hypothalamic nuclei cause shivering and blockage of sweat and thus regulate the body temperature. The mammillary nuclei, on the contrary, are believed to be involved in the memory function.
Functions of Hypothalamus
Following are the important functions of the hypothalamus:
- Its main function is maintaining the body’s internal balance- homeostasis.
- It also connects the endocrine and the nervous system.
- Hypothalamus stimulates or inhibits many of the body’s activities to maintain homeostasis, such as regulating body temperature, appetite and body weight, heart rate and blood pressure, etc.
- It is involved in many essential functions of the body, including Childbirth, Emotions, Sleep cycles, Balancing body fluids, Appetite and thirst control, Blood pressure, and heart rate.
Hormones Secreted by Hypothalamus
The anterior region of the hypothalamus is responsible for hormone secretion. The nuclei present in this region lead the process. The important hormones secreted by the hypothalamus are:
- Corticotropin-Releasing Hormone: This hormone is responsible for the regulation of metabolic and immune responses.
- Thyrotropin Releasing Hormone: It triggers the pituitary gland to release a thyroid-stimulating hormone which plays a major role in the functioning of organs of the body such as the heart, muscles, etc.
- Gonadotropin-Releasing Hormone: It stimulates the pituitary gland to release several reproductive hormones.
- Oxytocin: It is involved in several processes such as lactation, childbirth, regulating sleep cycles, and maintaining body temperature.
- Somatostatin: It regulates the endocrine system and affects neurotransmission and cell proliferation by interacting with G-protein coupled receptors.