What is hypothalamus? functions and embryonic development of hypothalamus along with hypothalamic disorders

HYPOTHALAMUS

introduction

In the body at the same time various life sustaining process are being carried out and various organs works continuously to make various secretions that maintain that controls various metabolic activities endocrine activities exocrine activities of the body but every thing in the body needs a control and coordinating center to work properly and effectively and brain is the most important and crucial coordinating and control central of the body and this brain consist of various components and each components holds a great importance in the body all these whole components effects the whole body in some way. Among all the important components and the structures of the brain there is a structure that goes by the name of hypothalamus and in bodies of living organisms it have various importance such as it is responsible for building a link between the nervous system and the endocrine system through the Pituitary gland. Hypothalamus also produces various hormones that are known as hypothalamic hormones and they are responsible for the stimulation and inhibition of the hormones that are released from the pituitary gland  such that the hypothalamus and the pituitary gland have a functional relationship such as in case of many hormones they are produced in the hypothalamus and after their production they get stored in the pituitary gland  and are released from the pituitary gland according to the needs of the body. In human adult it is about size of an almond it is about 3-4 mm in thickness and its weight is about 4 grams and it is found along either side of the front end of the third ventricle and it just lies below the thalamus. Hypothalamus is almost completely hidden by the overlying cerebral hemisphere. Hypothalamus is connected with both of the anterior and posterior parts of the pituitary gland such that it is connected to the pituitary by a infundibulum or the pituitary stalk ans they are also connected by both nervous and chemical pathways. Posterior pituitary does not produces hormones but rather stores and secretes hormones that are produced by the hypothalamus unlike the posterior pituitary the anterior pituitary does produces hormones however the secretion of hormones from this part of the pituitary are stimulated or inhibited by the stimulation or inhibiting hormones produced from the hypothalamus. Hypothalamus is also responsible for the autonomic nervous system of the body. like the amygdala and the hippocampus hypothalamus is also a part of the forebrain's limbic system and in the body it controls various physiological features such as 

• hormone production
• playing its role as a major coordinating center
• body temperature regulations 
• feeling of hunger and fullness 
• mensuration cycle 
• water balance of the body 
• sleep and wake cycle 

hypothalamus is also responsive to various factors such as

• light 
• autonomic inputs 
• stress
• change in body temperature caused as a result of foreign microbial attack 
• steroidal hormones
• olfactory stimulus 

 like any other structure of the body hypothalamus needs a blood supply as well as a nervous supply. If we talk about the blood supply of the hypothalamus than we can say that the blood to the hypothalamus are given by

• anterior cerebral arteries 
• anterior communicating artery
• posterior communicating arteries  
• posterior cerebral arteries 
• basilar arteries 

hypothalamus communicates with the rest of the body through

• nervous connections 
• cerebrospinal fluid 
• endocrine system 

hypothalamus is packed with about ten to eleven small indistinct nuclei as hypothalamus is the portion of the brain that contains a number of small nuclei with a variety of functions and on the basis of the function and types of the nuclei the hypothalamus is divided into three main sections that are

• anterior region 
• posterior region 
• tuberal region 

 and the different types of nuclei found in these regions are as following

anterior region 

                                      anterior region of the hypothalamus consist of following nuclei 

• lateral nucleus 
• preoptic nucleus 
• paraventricular nucleus    
• medial preoptic nucleus 
• supraotic nucleus           
• anterior hypothalamic nucleus
• suprachiasmatic nucleus 

tuberal region 

                                          tuberal region of the hypothalamus consist of following nuclei      

• lateral nucleus 
• lateral tuberal nucleus 
• ventromedial nucleus 
• dorsomedial hypothalamic nucleus    

posterior region 

                          posterior region of the hypothalamus consist of following nuclei 

• tuberomammilary nucleus 
• lateral nucleus
• mammilary nuclei 
• posterior nucleus 

     

hypothalamus

embryonic development of the hypothalamus

Like any other organ of the bodies of the living organism hypothalamus also undergoes various development changes and various modifications during its embryonic developmental time that makes it a complete effective part of the body both structurally and functionally and than afterwards it plays its role in the body and maintains a balance in the body and despite of its size in an adult that is about the size of an almond it is one of the most major component of the body without which the body can't function properly. Hypothalamus in its early embryo stage acts as a neuroectoderm of the forebrain's that is the brain's primary vesicle that is further divided into  two secondary vesicles that are as following 

• diencephalon 
• telencephalon 

in the diencephalon's ventro-lateral wall's intermediate zone proliferation generates the primordial hypothalamus. hypothalamus development also occurs deferentially in males and females embryos that described as part of their neural sexual dimorphism. Hypothalamus along with the pituitary gland forms the hypothalamic endocrine axis. After the ventro-lateral wall's intermediate zone proliferation occurs than after this there is a formation of a small pea sized swelling from the mamillary bodies and it is the ventral wall of the hypothalamus. Hypothalamus is highly interconnected with other parts of the central nervous system in particular with brain stem and its reticular formation ans such that the retino hypothalamus tract is the main connection between the eyes and the hypothalamus and it acts as a direct pathway from the retina going thought the optic chiasma. Several hypothalamic nuclei are sexually dimorphic such that there is a clear difference in both structures and functions between the males and the females. Hypothalamus coordinates many hormonal and behavioral circadian rhythms complex patterns of neuroendocrine outputs complex homeostatic mechanisms and important behaviors.

functions of the hypothalamus  

As mentioned above we should have a clear concept at this point that posterior and the anterior pituitary does not produce their own secretions but they are effected by the hypothalamus in some ways such that if we talk about the posterior pituitary than we can say that it does not produce any hormones of its own but in turn it acts as store house for the hormones of the hypothalamus such as there are some hormones that are produced in the hypothalamus but after their production they are stores in the posterior pituitary and they are than released according to the needs of the body where as in case of the anterior pituitary it produces its own hormones but there productions are directly influenced by the hypothalamus such that its secretions are inhibited or stimulated by the inhabiting or stimulating factors or hormones that are released by the hypothalamus because hypothalamus has a central nureoendorcine function such as if we talk about the anterior pituitary these inhibiting or stimulating factors after being released from the hypothalamus gets released into the the capillaries of the third ventricle and travel through the hypothalamus pituitary portal circulation and once they reach their destination in the anterior pituitary these hormones binds to specific receptors located on the surface of the pituitary cells  depending on which cells are activated through this binding the pituitary will either begin secreting or stop secreting following hormones into the blood stream and the hormones released from the hypothalamus that influence the anterior pituitary are as following  

• thyrotropin releasing hormone  (prolactin releasing hormone) 
• corticotropin releasing hormone 
• dopamine (prolactin inhibiting hormone)
• growth hormone releasing hormone
• gonadotropin hormone 
• somatostain 

where as in case of the posterior pituitary there is no production of its own hormone but in fact it stores the hormones that are produced from the hypothalamus and release them in case of need and the hypothalamic hormones that are stored in the posterior pituitary are as following

• oxytocin 
• vasopressin 

hypothalamus is also responsible for maintaining many physiological functions of the body such as

• hormone production 
• playing its role as a major coordinating center
• body temperature regulations 
• feeling of hunger and fullness 
• mensuration cycle 
• water balance of the body 
• sleep and wake cycle 
• glandular secretions of the stomach and intestines 
• electrolyte balance of the body 
• heart rate 
• blood pressure 

diseases related to hypothalamus

Like any other gland of the body hypothalamus can also show abnormalities an can be nonfunctional and this can be because of any structural function genetic or secretion based reason that can affect the whole of the hypothalamus or some of its parts or some of its secretions. Some of the factors that can effect the normal functions of the hypothalamus are as following 

• genetic disorders 
• head injuries
• autoimmune conditions 
• brain surgeries 
• eating disorders 
• birth defects 

there are some of the common symptoms that can arise as a result of the diseases or disorder of the hypothalamus and the common symptoms that occur as a result of the abnormality in the hypothalamus are as following 

• insomnia 
• unusually high or low blood pressure 
• change in appetite 
• unexpected change in body weight 
• body temperature fluctuations
• infertility 
• delayed onset of puberty 
• dehydration 
•  frequent urination 

where these disorders and their general symptoms are on one side but we can improve our life and provide healthy environment to the hypothalamus so that it can grow properly and can function properly and for such changes we simply need to change our habits and our life style and the things that we have to add in our daily life to have a healthy structural and functions hypothalamus along with a healthy body as following 

• getting enough sleep 
• quitting smoking 
• lower stress levels 
• avoid drinking 
• proper and balanced die 
• and the most important daily exercise 

these are some of the general thing to maintain a healthy body. These were some of the symptoms that occurs as a result of various conditions of the hypothalamus and some of the preventive measures by which we can maintain a healthy body but there are some specific disorders of the hypothalamus that are as following  

• hypopituitarism
• diabetes insipidus
• Prader willi syndrome  

diabetes insipidus 

It is a condition in which the patient faces frequent urination or urge to urinate and along with the increased urination there is also an increased in thirst it can occur as a result of any abnormality occurring in the hypothalamus that causes disturbance in the levels of production of vasopressin and its release and this hormone controls the concentration of the urine formed and in this condition this vasopressin is very little to none produced and released there is very little to no re-absorption of the water and the bodies water is released from the urine causing a state of dehydration in the body. Some of the common symptoms of the diabetes insipidus are as following 

• extreme thirst 
• polyuria  
• colourless urine 
• waking frequently at night to urinate 
• dry skin
• constipation
• weak muscles 
• bed-wetting