hypothalamus explained

hypothalamus is arguably the most essential of the endocrine system(hormonal system). hypothalamus is located below the thalamus (a part of the brain that relays sensory information) and above the pituitary gland and brain stem. It is about the size of an almond. hypothalamus is responsible for the four Fs: fighting, fleeing, feeding, and fornication. Clearly, due to the frequency and significance of these behaviors, the hypothalamus is extremely important in everyday life.

The hypothalamus is involved in different daily activities like releasing hormones, controlling appetite, in the control of the body’s temperature and energy maintenance, and in the process of memorizing and in stress control. It also modulates the endocrine system through its connections with the pituitary gland.

although you do not necessary need to know them all, The hypothalamus has three main regions. Each one contains different nuclei. These are clusters of neurons that perform vital functions, such as releasing hormones.

  1. Anterior region is also called the supraoptic region. Its major nuclei include the supraoptic and paraventricular nuclei. There are several other smaller nuclei in the anterior region as well.
  2. Middle region is also called the tuberal region. Its major nuclei are the ventromedial and arcuate nuclei.
  3. Posterior region is also called the mammillary region. The posterior hypothalamic nucleus and mammillary nuclei are its main nuclei.

pituitary gland is a hormone-secreting gland that sits just below the hypothalamus. It consists of two lobes called the anterior and the posterior pituitary

The connection of the hypothalamus to many other regions of the brain, including the cerebral cortex, allows intellectual and functional signals, as well as external signals, including physical and emotional stresses, to be funneled from the hypothalamus to the endocrine system. From the endocrine system these signals are able to exert their effects throughout the body.

although the actions of body are all connected together, Hypothalamus roles are divided into two main categories, nervous system and endocrine system, and homeostasis.

hypothalamus and nervous system

hypothalamus plays a role in autonomic nervous system. It processes sensory impulses received from the smooth muscle within the body which lines organs such as the intestines and stomach, as well as blood vessels. By processing the impulses, the hypothalamus is able to regulate the movement of food, heart rate, and the contraction of the bladder.

Through the coordination of stimuli and processes, the hypothalamus can regulate eating behavior by promoting feelings of satiety. During the consumption of food, an area of the hypothalamus is activated when the stomach is full. Upon activation, the hypothalamus sends signals to promote feelings of satiety to reduce the need for further consumption. Research has found that damage to this particular area of the brain is linked to cases of excessive eating resulting in obesity.

The hypothalamus is highly involved in pituitary gland function. When it receives a signal from the nervous system, the hypothalamus secretes substances known as neurohormones that start and stop the secretion of pituitary hormones.

Within the hypothalamus is suprachiasmatic nucleus (SCN), commonly referred to as circadian pacemaker, which is responsible for the regulation of sleep/wake cycles. During the light cycle, a series of mechanisms deriving from the retinal ganglionic cells to the SCN prevent the secretion of melatonin. By preventing the release of the hormone, individuals are motivated to stay away during daylight hours. As the day progresses, and light signals to the retinal ganglion cells subside due to lack of sunlight, the SCN is inhibited and instead activates the paraventricular nucleus. As a result of this, sleepiness is induced due to the stimulation of the sympathetic nervous system, and the pineal gland begins to release melatonin.

hypothalamus and hormones

hypothalamus secretes substances into the bloodstream that are known as releasing hormones. They are so named because they travel to the anterior pituitary and cause it to release hormones that have been synthesized in the pituitary gland. Hormones released by the anterior pituitary due to signals from the hypothalamus (and their general role in parentheses) include growth hormone (GH), follicle-stimulating hormone (FSH is responsible for sexual development and reproduction), luteinizing hormone (LT is responsible for testosterone production and reproduction), adrenocorticotropic hormone (stress/fear response), thyroid simulating hormone (TSH plays an important role in the function of many body parts, such as heart, gastrointestinal tract, and muscles and also helps with metabolism), and prolactin (milk production).

Hypothalamus itself produces multiple hormones, one of them is s hormone called Corticotropin-releasing hormone (CRH). CRH sends a message to the anterior pituitary gland to stimulate the adrenal glands to release corticosteroids, which help regulate metabolism and immune response.

The hypothalamus also synthesizes oxytocin and vasopressin hormones. These are then sent to the posterior pituitary for release into the bloodstream. Oxytocin can act as a hormone and a neurotransmitter. It has important roles in facilitating childbirth (hence the use of Pitocin to induce labor) and lactation, but also has been the subject of a lot of recent research due to its hypothesized role in compassion and social bonding. Vasopressin’s main functions are to control urine output and regulate blood pressure, although it also seems to play a part in social and sexual behavior.

Hypothalamus  also secretes hormone such as Anti-diuretic hormone (ADH which increases water absorption into the blood by the kidneys), Gonadotropin-releasing hormone (GnRH stimulates the anterior pituitary to release follicle stimulating hormone and luteinizing hormone (LH) that we mentioned), Growth hormone-releasing hormone(GHRH also known as somatocrinin prompts the anterior pituitary to release growth hormone) and growth hormone-inhibiting hormone(GHIH also known as Somatostatin has the opposite effect. Somatostatin works to stop the pituitary gland from releasing certain hormones, including growth hormones and thyroid-stimulating hormones.

In children, GH is essential to maintaining a healthy body composition. In adults, it aids healthy bone and muscle mass and affects fat distribution.

The other hormone which is secreted from hypothalamus is Thyrotropin-releasing hormone (TRH). TRH production stimulates the pituitary gland to produce thyroid-stimulating hormone.

Dopamine secretion also takes place in hypothalamus. Dopamine is a type of neurotransmitter. Your body makes it, and your nervous system uses it to send messages between nerve cells. That’s why it’s sometimes called a chemical messenger. Dopamine plays a role in how we feel pleasure.

hypothalamus and homeostasis

Homeostasis is the maintenance of equilibrium in a system like the human body. Optimal biological function is facilitated by keeping things like body temperature, blood pressure, and caloric intake/expenditure at a fairly constant level. The hypothalamus receives a steady stream of information about these types of factors. When it recognizes an unanticipated imbalance, it enacts a mechanism to rectify that disparity.

as mentioned hypothalamus can restore homeostasis is through the control of hormone release from the pituitary gland.

Hypothalamus also plays a huge role in balance of electrolytes and fluid maintenance.

aside from endocrine system, The hypothalamus has connections to the autonomic nervous system, through which it can send signals to influence things like heart rate, digestion, and perspiration. For example, If the hypothalamus receives a signal that the internal temperature is too high, it will tell the body to sweat. If it receives the signal that the temperature is too cold, the body will create its own heat by shivering.

Symptoms of hypothalamic conditions

A hypothalamic disease is any disorder that prevents the hypothalamus from functioning correctly. These diseases are very hard to pinpoint and diagnose because the hypothalamus has a wide range of roles in the endocrine system.

The hypothalamus also serves the vital purpose of signaling that the pituitary gland should release hormones to the rest of the endocrine system. As it is difficult for doctors to diagnose a specific, incorrectly functioning gland, these disorders are often called hypothalamic-pituitary disorders.

Research has found that atypical development may lead to a plethora of issues such as depression and sleep disorder caused by abnormalities in the hypothalamic circuits.

A physical injury to the head that impacts the hypothalamus is one of the most common causes of hypothalamic disease.

Some hypothalamic diseases have a genetic link to hypothalamic disease. For instance, Kallman syndrome causes hypothalamic problems in children, most noticeably delayed or absent puberty, accompanied by an impaired sense of smell.

Hypothalamus problems also appear to have a genetic link in Prader-Willi Syndrome. This is a condition in which a missing chromosome leads to short stature and hypothalamic dysfunction.

Additional causes of hypothalamic disease can include:

  • eating disorders, such as bulimia or anorexia
  • genetic disorders that cause excess iron buildup in the body
  • malnutrition
  • infections
  • excessive bleeding

a few symptoms that could be a signal of hypothalamus problems are:

  • unusually high or low blood pressure
  • body temperature fluctuations
  • unexplained weight gain or loss
  • changes in appetite
  • insomnia
  • infertility
  • short stature
  • delayed onset of puberty
  • dehydration
  • frequent urination

Hypothalamic dysfunction plays a role in many conditions, including:

  • Diabetes insipidus. If the hypothalamus doesn’t produce and release enough vasopressin, the kidneys can remove too much water. This causes increased urination and thirst. Unlike people with diabetes mellitus, people with diabetes insipidus have stable blood sugar levels.
  • Prader-Willi syndrome. This is a rare, inherited disorder. It causes the hypothalamus to not register when someone is full after eating. People with Prader-Willi syndrome have a constant urge to eat, increasing their risk of obesity. Additional symptoms include a slower metabolism and decreased muscle.
  • Hypopituitarism. This disorder happens when the pituitary gland doesn’t produce enough hormones. While it’s usually caused by damage to the pituitary gland, hypothalamic dysfunction can also cause it. Many hormones produced by the hypothalamus directly affect those produced by the pituitary gland.

What foods are good for hypothalamus?

Research has also demonstrated that diets high in saturated fats might have an inflammatory effect on the body.

This can make the immune system overactive, increasing the chances of it targeting healthy body cells, increasing inflammation in the gut, and altering the natural working of the body.

Diets high in polyunsaturated fats, like omega-3 fatty acids, can help to reverse this inflammation. These fats might be a safe alternative to other types of oils and fats. Foods with high omega-3 content include fish, walnuts, flax seeds, and leafy vegetables.

Additional healthy dietary choices to support the hypothalamus and best brain function include:

  • vitamin-rich fruits and vegetables
  • zinc
  • vitamin C
  • B-vitamins