Hypothalamus

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Introduction

The hypothalamus is an important part of the brain. It is a gland-like organ that performs many functions. It works with the pituitary gland to help control blood pressure, temperature, hunger, thirst, sleep cycles, and emotions.

The hypothalamus controls body temperature by vasoconstriction or vasodilation to the skin. Vasoconstriction means that blood vessels restrict flow to the skin. This prevents heat from escaping outwards toward the atmosphere. Vasodilation means that blood vessels enlarge and allow more blood to reach the skin.

The blood brings heat from deeper within the body towards the surface of the skin so that it can be released into the atmosphere due to conduction and convection. For example, when you exercise in cold weather your body will vasoconstrict because it needs all available heat to stay warm. When you stop exercising your body will vasodilate because it can release some of this stored heat into the environment.

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The hypothalamus also helps control thirst and hunger through a variety of neural pathways. It controls hunger by not allowing you to pass into a fasting state until it is determined that your energy balance is negative enough to trigger starvation mode (which is when you begin burning stored fats and proteins as energy).

Likewise, it controls thirst by not allowing you to pass into a dehydrated state until it is determined that your energy balance is positive enough to trigger satiety mode (which is when you begin storing fats and proteins as energy).

Structure of Hypothalamus

The hypothalamus is a small region in the brain, but it has a big job to do. It's responsible for maintaining homeostasis−the balance of all the systems in the body−and it also helps motivate us to move around and do things. It's kind of like the boss at work who makes sure everything is working smoothly, while also making sure everyone is being productive and having fun.

It's hard to pinpoint just one part of the brain as being "the hypothalamus," because it's very small and complex. But if we had to pick one region, we would say it's made up of parts called the dorsomedial nucleus (DMH), ventromedial nucleus (VMH), anterior nucleus (AN), and posterior nucleus (PO). All four of these regions help control hunger and thirst, as well as how much you eat or drink.

They also play a role in regulating temperature, sleep cycles, circadian rhythms, sexual behavior, blood pressure, and even emotions. These areas are closely connected with other parts of the brain that control things like vision and hearing.

The hypothalamus is located deep inside your brain and controls the pituitary gland by releasing hormones that regulate how much hormone gets released into your bloodstream. If your hypothalamus is damaged, the pituitary gland doesn’t receive the right signals and can’t release enough hormones to control your body. This can cause serious problems with growth or sexual development, as well as fertility.

Anterior Region

The anterior portion of the hypothalamus is located just above the optic chiasm at the base of the brain. It regulates body temperature and water balance through its influence on the sweat glands and kidneys. The anterior region also controls sexual behavior and reproduction by regulating the pituitary gland (which produces hormones that stimulate or inhibit other endocrine glands).

Middle Region

The middle region extends from just below the optic chiasm to just above it. It regulates hunger, thirst, fatigue and emotions such as anger and fear. This area also controls body temperature and blood pressure through its effects on brown adipose tissue (BAT) in newborns. BAT helps maintain a constant body temperature by burning energy stores when they're needed most (e.g., during cold weather).

Posterior Region

The posterior region of the hypothalamus controls temperature regulation and water balance in your body by releasing hormones that regulate sweating, urination and other bodily functions related to fluid balance such as thirst and hunger sensations.

Functions of Hypothalamus

The functions of the hypothalamus include−

  • Regulation of body temperature

  • Regulation of hunger, thirst and appetite

  • Controls release of hormones that affect growth and development (e.g. prolactin, growth hormone)

  • Controls the release of hormones that regulate water balance, emotions, sexual behavior and reproduction (e.g. gonadotropin-releasing hormone)

  • Controls sleep cycles and wakefulness (through connections to other parts of the brain)

Hormones secreted by Hypothalamus

The hormones secreted by the hypothalamus are−

Somatostatin − It controls growth hormone release from the pituitary gland.

Oxytocin − It stimulates milk letdown during breastfeeding, uterine contractions during labor, and contraction of the nipples at birth.

Corticotropin-releasing hormone (CRH) − It stimulates corticotropin (ACTH) release from the anterior pituitary gland; ACTH stimulates adrenal cortex activity resulting in increased production of glucocorticoids (such as cortisol).

Growth hormone-releasing hormone (GHRH) − It stimulates growth hormone release from the anterior pituitary gland; growth hormone promotes linear growth and protein synthesis.

Oxytocin

Oxytocin is a naturally occurring hormone that is released during positive social experiences. The hormone is produced in the hypothalamus and stored in the pituitary gland, and its release is regulated by the limbic system (the part of the brain responsible for emotions).

The name comes from the Greek words for "swift" and "to lead," aptly describing how this chemical works. It's both an endocrinological messenger, meaning it controls many body functions including breathing, digestion, heart rate, blood pressure, immune function, sexual arousal and bonding, memory formation, sleep regulation, thermoregulation−the list goes on−and it's also a neurotransmitter (which means it travels through the central nervous system to other nerve cells and affects how they work).

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As far as its effects on human behavior are concerned, Oxytocin has been found to be involved in social recognition, trust and attachment.

Oxytocin can be released when you're doing something pleasurable or exciting. It might come up in casual conversation with a friend or coworker or your spouse; it might be released while engaging in stimulating and rewarding activities like dancing or learning something new; we may even find ourselves experiencing a spike after eating delicious food.

This is all good news for us −it means that we're not limited to experiencing the effects of Oxytocin only when we're having sex, or while breastfeeding a newborn. The bottom line is that the more you take care of your body and mind, the more likely it is that you'll experience those feel-good feelings and see them as a sign of well-being.

ADH: Anti-diuretic Hormone

Anti-diuretic hormone (ADH) is a hormone that regulates the amount of water that the kidneys remove from the bloodstream; it does so by controlling the permeability of the kidney's collecting ducts to water. It is released from the posterior pituitary gland in response to high levels of salt and calcium in the bloodstream, causing the kidney to retain sodium and water, thus lowering blood pressure and increasing blood volume. ADH has also been shown to reduce urine production, thereby lowering blood volume and reducing blood pressure.

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Diuretics like alcohol temporarily suppress ADH production, leading to increased urination (and therefore more rapid dehydration). This is how diuretics work− they induce urination by stimulating receptors in the brain called ADH receptors, which then signal for ADH production. This works in tandem with another brain receptor called a v2-receptor that stimulates thirst. When you drink water or a diuretic substance, both receptors are triggered−the v2-receptor tells you that you are thirsty, while the ADH receptors tell your kidneys to produce more urine.

Conclusion

The hypothalamus is a small, but important, part of the brain that controls many vital functions. It is responsible for regulating the body's temperature, hunger, thirst, and sleep cycles. It also plays a role in controlling emotions and stress levels. Although the hypothalamus is a small structure, it is essential for maintaining the body's homeostasis and ensuring its overall health and well-being.

FAQs

1. What does the hypothalamus do?

As we mentioned, the hypothalamus is responsible for regulating a variety of bodily functions. It helps to maintain homeostasis, or balance, in the body by coordinating the actions of the nervous and endocrine systems.

2. What happens if the hypothalamus is damaged?

Damage to the hypothalamus can lead to a variety of problems, including disruptions in body temperature, appetite, and hormone release. It can also cause problems with sleep, mood, and blood pressure.

3. What diseases are associated with the hypothalamus?

There are a few diseases that are associated with the hypothalamus, including diabetes insipidus and syndrome of inappropriate antidiuretic hormone secretion (SIADH).

4. How can I keep my hypothalamus healthy?

There's no surefire way to prevent hypothalamus damage, but there are a few things you can do to keep your hypothalamus healthy. Eating a healthy diet, exercising regularly, and getting enough sleep are all good ways to keep your hypothalamus functioning properly.

raja
Updated on 13-Oct-2022 11:19:47
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