The brain maintains the stable internal environment as homeostatic and regulation by action signals and messaging. Neural control canters in the brain influence body glands to produce and release hormones needed to maintain a synchronized balance. 

So we know that the whole system of our body’s state of stability,  in the internal state of homeostasis,  is extremely important for the balanced system in the brain to work with internal environments,  and external environments that we exist with. 

Through the actions of hormones, and neural control centers in the brain, influencing the body’s glands to produce and release hormones which are necessary to maintain and hold this vital balance. Without it we could not operate. Hormone and control glands are organs that respond to the imbalance of the whole system in order to regulate the action taking place. For example the absorption of nutrients, and the intake of water or food. They react by “increasing or decreasing” hormones, which then travel to targeted organs where they hook onto specialized receptors on the (surface of cells). This is called “binding” and it causes a physiological change that restores the homeostasis.  It is being monitored, and maintained at all levels and at all times during our 24 hour day.

The hypothalamus is the “link” between the nervous systems of Central Nervous System and the Autonomous nervous systems, and the endocrine is the system that releases the hormones that in turn trigger the “Pituitary Gland” to either start or stop secreting it’s hormones.

Hormones released by the Pituitary Gland “melancyte” stimulating hormones that stimulate the production of the determinant of skin colour and hair colour.  

“Adrenacorticotropic Hormone” triggers the adrenal glands to produce steroid hormones,  the cortico stress response. 

Thyroid stimulating hormones increase the activity of the “thyroid glands” which controls the metabolism. 

“Growth hormones” act on the entire body but especially for the growth and development of the children. 

“Luteinizing hormone” and follicle stimulating hormones trigger sex glands in males  and females,  to make their own hormone. 

“Oxytocin” causes contraction during labour also involved in the release of milk from the mammary gland. 

“Prolactin”stimulates the production of milk from the mammary glands.

“Antidiuretic  Hormones”  control the amount of water removed from the blood by microfibers in the kidneys.

Feedback Mechanisms;

Imbalances are detected and corrected using feedback mechanisms or loops for regulation, Levels of hormones within the blood stream are gauged and the information sent to the control unit in charge of that said hormone, which in most cases is the hypothalamus – pituitary unit. If the level of hormones is high the control unit responds by reducing the production of the hormone  to achieve balance. Feedback mechanisms are also used to trigger rare homeostasis functions such a contractions during labour.  The hypothalamus detects rising blood glucose levels producing fewer hormones for the pituitary gland. The Pituitary glands reach to drop a hormone level by releasing fewer hormones from the thyroid. The thyroid gland produces fewer hormones that stimulate glucose production. Negative feedback is in response to a rise in blood glucose, where the hypothalamus triggers a chain reaction of reduced hormone production that results in a fall of glucose levels which restore balance. Hormone producers in the  “neuroendocrine” system have unique roles to play synthesizing specific hormones for specific purposes. The action of these hormones help maintain ;

                                                   

 “OPTIMAL INTERNAL ENVIRONMENTS” 

                                                                   

TO DEAL WITH THE

                                                     

“COMPLEX EXTERNAL ENVIRONMENT” 

 

The “Pineal gland” near the hypothalamus in location, makes “melatonin” a hormone crucially involved with the sleep – wake cycle.

The “Hypothalamus”  is a vital link between the nervous systems called the Central Nervous System and the Autonomous Nervous System, and the neuroendocrine system produces two of it’s own hormones.

The “Pituitary gland” in the temporal lobe in front of the ear, is known as the “master gland.” because it controls many of the other endocrine glands manufacturing 8 hormones and receiving two directly from the hypothalamus. 

The “thyroid gland” just above the v bone in the throat area produces hormone development of white blood cells. 

The “Heart”  produces the hormone “atriopeptin” that reduces blood volume and pressure. 

The “Oxytocin” makes hormones that stimulate production and release enzymes of digestion.

The “stomach” makes hormones that stimulate production and release production of enzymes that aids digestion.

The “Adrenal Glands” produce hormones that regulate metabolism of glucose, sodium and potassium, and also produces epinephrine.

The kidney secretes “erythrapoletin,” stimulating the production of red blood cells and bone marrow.

The “Pancreas” produces insulin and glucose which raises and lowers blood glucose levels. 

The “Intestines” manufacture hormones  that stimulate production or release enzymes that aid digestion. The “Ovaries” produce the female hormones estrogen and progesterone.

Hunger;

The whole system maintains it’s weight at a set point by using hormones to trigger sensations of “hunger or satiety.” To stimulate appetite the stomach produces the hormone “grehlin”  while fat tissue decreases the production of leptin insulin. These changes signal to specific neurons type B to start production of “neuropeptides.” The production of these neurons cause other neurons type A to which the production of the hormone of “melanocartin” an inhibitor which works to suppress appetite. These signals are transmitting to the lateral hypothalamus which generates the sensation of hunger. The system to suppress appetite creates “leptin.” These hormones signal to type B neurons to inhibit production of NPY (neuropeptides) and ACRP at the same time. At the same time the increased “leptin” and insulin triggers neurons type A to produce “melanocartin.” All these signals reach the hypothalamus to create the “feeling of Satiety.” 

(1) The stomach fat tissues  – decrease leptin and insulin. + Increasing production of “grehlin.”

(2) Neuron B stimulates production of neuro-peptides (NPY) and Agouth Related Peptides (AGP). 

(3) Neuron A inhibits production of (- melanocarton). 

(4) Neurons pass on the stimuli to the Lateral Hypothalamus creating the sensation of hunger. 

SUGAR ADDICTION;

As a reward system ” a Reward for performing functions” essential for the survival of both the individual and the species,  such as eating or reproducing, the brain releases “Opiates,” that create sensations, feelings, emotions, pleasure, on sugar rich diets. Sugar rich diets generate heightened reward signals, so that the more you have the more you want. This can override the “Self” control mechanisms in place and lead to addiction.  The “Ventral Tegmental area the VTA,” where the dopamine flows to the Nucleus Accumbens  to the Basal Ganglia in the brain, is called the “Reward System.”

The VTA is in the mid brain processing information about how well various needs detect these changes and in response the Pituitary gland releases Antidiurectic (ADH) hormone which act on the kidneys to retain water, producing less urine. The kidneys release the enzyme “remin” into the blood stream which through a series of reactions, forms the hormone “Angiotensin” This is detected by the “Subfornical Organ” which is connected to the hypothalamus,  which in turn activates more “Antidiuretic Hormone” producing cells and creating the sensation of thirst, leading to the balance of systems.

Water deprivation;

(1) The kidneys retain water and secrete “Renut” into the blood stream. This was a chain of reactions to form “Angiotensin.”

(2) It goes to the “Subfornical Organ,” which has cells that project into the hypothalamus detecting “Angiotenin” stimulating the Lateral Hypothalamus.

( 3) The hypothalamus detects changes and brings about the release of Antidiurectic Hormones (ADH) producing cells in the hypothalamus area creating thirst.

(4) Drinking – Water level balance, and  restoring system balance in the whole system. 

(5) Not drinking or water deprivation causes (1) Blood Volume decrease and (2) Salt Concentration Increase Unbalanced health.

The Sleep and Wake Cycle;

The Suprachiasmatic nucleus (SCN) in the hypothalamus plays a big role in the sleep wake cycle. Light levels are sensed by the retina and this information is relayed to the SCN which then sends a signal to the Pineal Gland. This triggers the release of “melatonin.” This hormone tells the body when to sleep. At this point the brain becomes less alert and fatigue stands to take over. When melatonin levels fail in response to increased light the waking part of the cycle begins.

Melatonin; 

 When we have falling levels of light, production of melatonin forms a link between the EXTERNAL ENVIRONMENT,  and the INTERNAL ENVIRONMENT  which triggers the circadian sleep wake cycle. 

The Next Writing will be on “Planning.”

This article is supported by Writings of Rita Carter “The Brain,” and the Jeanette Norden University class of Neuroscience
Understanding the Brain.” plus many other biology courses previously taken and research of my own over 40 years of study.  The Brain Unifies Us All around the world. 

Carolyn d Hogarth, the wife of Colin D Hogarth Canada. 🙂