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Hypothalamus

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Controls hunger and fullness.
 

The hypothalamus is the primary organ responsible for regulating metabolism.

 

The hypothalamus is located on the diencephalon and forms the floor and part of the lateral walls of the third ventricle of the cerebrum. 

The lateral hypothalamic area controls the sensation of hunger.

The ventromedial nucleus of the hypothalamus controls the sense of satiety.

That part  of the brain that contains a number of small nuclei with a variety of functions. 

 

Among the functions of the hypothalamus are control and integration of activities of the autonomic nervous system (ANS)

The hypothalamus, just above the brain stem, acts as an integrator for autonomic functions, receiving ANS regulatory input from the limbic system to do so.

The ANS regulates contraction of smooth muscle and cardiac muscle, along with secretions of many endocrine organs such as the thyroid gland.

 

Through the ANS, the hypothalamus is the main regulator of visceral activities, such as heart rate, movement of food through the gastrointestinal tract, contraction of the urinary bladder, 

production and regulation of feelings of rage and aggression, regulation of body temperature and 

regulation of food intake.

 

Functions of hypothalamus: 

 

releasing hormones

 

regulating body temperature

 

maintaining daily physiological cycles

 

 

controlling appetite

 

managing of sexual behavior

 

regulating emotional responses

 

It’s located at the base of the brain, near the pituitary gland.

 

The hypothalamus links the nervous system to the endocrine system via the pituitary gland. 

 

It is located below the thalamus and is part of the limbic system.

 

It forms the ventral part of the diencephalon. 

 

It is the size of an almond.

 

It  is responsible for the regulation of certain metabolic processes and other activities of the autonomic nervous system. 

 

The hypothalamus synthesizes and secretes neurohormones, called releasing hormones which in turn stimulate or inhibit the secretion of hormones from the pituitary gland. 

 

The hypothalamus controls body temperature, hunger, important aspects of parenting and attachment behaviors, thirst, fatigue, sleep, and circadian rhythms.

 

The hypothalamus is a divided into 3 regions: supraoptic (anterior) , tuberal,

 

 ( middle), mammillary (posterior).

 

Each region  contains different nuclei. 

 

These are clusters of neurons that perform vital functions, such as releasing hormones.

 

Neurohypophysial hormones are produced by neurosecretory cells in the paraventricular nucleus in  the supraoptic nucleus of the hypothalamus:  

 

oxytocin and vasopressin. 

 

These hormones are subsequently released into the blood in the posterior pituitary.

 

Smaller parvocellular neurosecretory cells, of the paraventricular nucleus, release corticotropin-releasing hormone and other hormones into the hypophyseal portal system, where these hormones diffuse to the anterior pituitary.

 

The anterior area is also called the supraoptic region. 

 

The anterior area’s  major nuclei include the supraoptic and paraventricular nuclei, among several other smaller nuclei.

 

 Some of the most important hormones produced in the anterior region include:

 

Corticotropin-releasing hormone (CRH). 

 

Thyrotropin-releasing hormone (TRH). 

 

Gonadotropin-releasing hormone (GnRH). 

 

Oxytocin

 

Vasopressin

 

CRH is involved in the body’s response to both physical and emotional stress., and signals the pituitary gland to produce adrenocorticotropic hormone (ACTH). 

 

ACTH triggers the production of cortisol, an important stress hormone.

 

Thyrotropin-releasing hormone (TRH). TRH production stimulates the pituitary gland to produce thyroid-stimulating hormone (TSH). 

 

TSH plays an important role in the function of many body parts, such as the heart, gastrointestinal tract, and muscles.

 

Gonadotropin-releasing hormone (GnRH) production causes the pituitary gland to produce important reproductive hormones, such as follicle-stimulating hormone (FSH) and luteinizing hormone (LH).

 

Oxytocin hormone controls many behaviors and emotions, such as sexual arousal, trust, recognition, and maternal behavior. 

 

Oxytocin is involved in some functions of the reproductive system, such as childbirth and lactation.

 

Vasopressin, also called antidiuretic hormone (ADH), regulates water levels in the body. 

 

When vasopressin is released, it signals the kidneys to absorb water.

 

Somatostatin works to stop the pituitary gland from releasing certain hormones, including growth hormones and thyroid-stimulating hormones.

 

The anterior hypothalamus also helps regulate body temperature through sweat. 

 

The anterior hypothalamus maintains circadian rhythms. 

 

The middle region of the hypothalamus area is also called the tuberal region. 

 

The middle region of the hypothalamus’ major nuclei are the ventromedial and arcuate nuclei.

 

The ventromedial nucleus helps control appetite.

 

The arcuate nucleus of the hypothalamus is involved in releasing growth hormone-releasing hormone (GHRH). 

 

GHRH stimulates the pituitary gland to produce growth hormone.

 

The posterior area is also called the mammillary region: The posterior hypothalamic nucleus and mammillary nuclei are its main nuclei.

 

The posterior hypothalamic nucleus helps regulate body temperature.

 

The posterior hypothalamic nucleus causes  shivering and blocking sweat production.

 

Causes of hypothalamic dysfunction, include:

 

head injuries

 

genetic disorders, such as growth hormone deficiency

 

birth defects involving the brain or hypothalamus

 

tumors in or around the hypothalamus

 

eating disorders, such as anorexia or bulimia

 

autoimmune disorders 

 

surgery involving the braiN

 

Hypothalamic dysfunctions/conditions:

 

Diabetes insipidus.

 

Prader-Willi syndrome.

 

Hypopituitarism.

 

Symptoms of hypothalamic depend on the part of the hypothalamus and types of hormones involved.

 

Symptoms suggesting a hypothalamus problem include:

 

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

 

Eating a balanced diet is especially crucial when it comes to the hypothalamus, as high lipids and sugar content have adverse effects found on laboratory studies.

 

Inadequate sleep is associated 

 

with hypothalamic dysfunction and  may increase risk of neurological diseases.

 

Regular exercise reduces hypothalamic inflammation related to a high-fat diet. 

 

 

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