Saturday, August 13, 2022

What Part Of The Brain Regulates Hunger And Thirst

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How Does Our Brain Control Hunger

Brain and hunger – Intro to Psychology

It begins with a low murmur that we only learn about ourselves, but soon turns into an impossible to disguise roar that catches the attention of everyone around us.

Our guts are leaving us a clear message, there is hunger and if we do not eat soon it is possible that we begin to notice other signs such as weakness and irritability.

The appetite regulating center is located in the brain. The one in charge of carrying out this process is an enzyme called AMPK and according to a study by the Institute of Science and Technology of Daegu it is possible to modify its behavior.

The way the brain perceives that we need to eat has to do with the process by which we adjust our weight, so that there can be a balance between the energy provided by the food we eat and the expenditure made by our body.

AMPK plays an important role in this process, an enzyme complex present in most organs of the body liver, muscle, adipose cells.. which is related to a cellular recycling program, autophagy, which acts as a metabolic regulator: detects cellular energy and helps the cells energy balance and calorie consumption.

When we go without food for a long time, hunger-inducing neurons set off a process called autophagy, which is a natural self-destruct mechanism through which cells recycle and discard internal structures that are no longer useful to them.

In this case, they help us understand why our character can change so much when we are hungry.

What Are The Parts Of The Brain

The brain has three main sections: the forebrain, the midbrain, and the hindbrain.

The Forebrain

The forebrain is the largest and most complex part of the brain. It consists of the cerebrum the area with all the folds and grooves typically seen in pictures of the brain as well as other structures under it.

The cerebrum contains the information that essentially makes you who you are: your intelligence, memory, personality, emotion, speech, and ability to feel and move. Specific areas of the cerebrum are in charge of processing these different types of information. These are called lobes, and there are four of them: the frontal, parietal, temporal, and occipital lobes.

The cerebrum has right and left halves, called hemispheres. They’re connected in the middle by a band of nerve fibers that lets them communicate. These halves may look like mirror images of each other, but many scientists believe they have different functions:

  • The left side is considered the logical, analytical, objective side.
  • The right side is thought to be more intuitive, creative, and subjective.

So when you’re balancing your checkbook, you’re using the left side. When you’re listening to music, you’re using the right side. It’s believed that some people are more “right-brained” or “left-brained” while others are more “whole-brained,” meaning they use both halves of their brain to the same degree.

In the inner part of the forebrain sits the thalamus, hypothalamus, and :

The Midbrain

The Hindbrain

The Cerebral Cortex Creates Consciousness And Thinking

All animals have adapted to their environments by developing abilities that help them survive. Some animals have hard shells, others run extremely fast, and some have acute hearing. Human beings do not have any of these particular characteristics, but we do have one big advantage over other animals we are very, very smart.

You might think that we should be able to determine the intelligence of an animal by looking at the ratio of the animals brain weight to the weight of its entire body. But this does not really work. The elephants brain is one-thousandth of its weight, but the whales brain is only one ten-thousandth of its body weight. On the other hand, although the human brain is one-sixtieth of its body weight, the mouses brain represents one-fortieth of its body weight. Despite these comparisons, elephants do not seem 10 times smarter than whales, and humans definitely seem smarter than mice.

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Patterns Of Eating And Drinking

Eating and drinking are behaviors that provide essential sustenance, sensory reward and social context. Consequently, they comprise a considerable proportion of daily activity. According to the 2007 Bureau of Labor Statistics American Time Use Survey and Educational Research Service Eating and Health Module , a representative sample of Americans over the age of 15 years of age ate and drank a mean of approximately 157 minutes daily. This was the primary activity for about 67 minutes and a secondary activity for the balance. Drinking represented almost 72% of secondary eating and drinking. In only 36% of instances eating and drinking were concurrent as secondary events. However, there is considerable inter-individual variability in these estimates. About 11.1% of the population reported drinking a mean of 8.2 hours per day. Add to this, the time spent thinking of eating and drinking , acquiring foods and beverages , as well as preparation and clean-up time and it is clear that from a time management perspective, this is a highly motivated activity.

Feeding As A Consequence Of Drinking

The Brain

Can decreased drinking behavior be the cause of decreased food intake? We believe so. Obestatin was originally identified as a posttranslational product of the ghrelin preprohromone . It was named on the basis of its apparent ability to inhibit feeding, an activity that was almost immediately challenged by other researchers . In our hands, central administration of obestatin did reduce food intake to a slight but not significant degree however, more impressive was the effect to inhibit water drinking in those same animals for up to 24 h after central administration before the onset of the dark phase . This inhibition of water, but not food, intake resulted in a significant loss of body weight over the 24-h period. The fact that neither food intake nor open field locomotor behaviors were altered by these same doses of obestatin suggested to us that the action of the peptide was selective for thirst. To test this possibility more directly, we examined the action of obestatin on pharmacologically driven thirst and observed a significant inhibitory effect of obestatin on angiotensin IIinduced water drinking . Water drinking in response to a hypovolemic challenge also was inhibited by intracerebroventicularly administered obestatin . Finally, we identified the subfornical organ as the potential site of the action of obestatin , again suggesting a unique action of the peptide on thirst mechanisms, independent of any significant action on food intake.

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What Controls Our Hunger

The hypothalamus houses the hunger and satiety centers. Several neural centers in the hypothalamus are involved in the control of food intake. The lateral nuclei of the hypothalamus act as the feeding center, because when stimulated they excite a voracious appetite .

In contrast, the destruction of the lateral hypothalamus cancels the desire for food and leads to progressive starvation, a state characterized by noticeable weight loss, muscle weakness, and reduced metabolism.

The lateral hypothalamic feeding center emits motor impulses for foraging. Rather, the ventromedial nuclei of the hypothalamus serve as an important satiety center and are believed to confer a sense of nutritional pleasure that inhibits the eating center.

Electrical stimulation of this region can induce complete satiety and, in fact, when very appetizing foods are offered, the animal rejects them .

On the contrary, the destruction of the ventromedial nuclei motivates a voracious and continuous feeding until the animal reaches extreme obesity, sometimes quadrupling its weight.

The paraventricular, dorsomedial, and arcuate nuclei of the hypothalamus are also believed to be instrumental in regulating food intake.

For example, lesions of the paraventricular nuclei usually lead to overeating, while those of the dorsomedial nuclei generally reduce eating behavior.

The hypothalamus receives:

  • Signals from hormones released by adipose tissue,
  • Signals from the cerebral cortex that modify eating behavior.

Diet Tips For Hypothalamus Health

As the hypothalamus plays such a vital role in the body, it is very important to keep it healthy. While a person cannot fully avoid genetic factors, they can take dietary steps towards ideal hypothalamus health on a daily basis to reduce the risk of hypothalamic disease.

The hypothalamus controls the appetite, and the foods in the diet influence the hypothalamus. Studies have shown that diets high in saturated fats can alter the way the hypothalamus regulates hunger and energy expenditure.

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Neural Signals From The Gi Tract

The brain can evaluate the contents of the gut through vagal nerve fibres that carry signals between the brain and the gastrointestinal tract. Studies have shown that the brain can sense differences between macronutrients through these vagal nerve fibres. Stretch receptors work to inhibit appetite when the GI tract becomes distended. They send signals along the vagus nerve afferent pathway and ultimately inhibit the hunger centres of the hypothalamus.

What Makes Water So Refreshing

Internal Regulation: Thirst

After a while standing outside in the hot sun, a cold drink of water tends to feel instantly refreshing. You might also find that drinking a very sugary beverage feels equally refreshing but leaves you feeling thirsty again later. In both cases, it takes tens of minutes for that drink to have any effect on attributes like osmolality or blood pressure, the bodys main indicators of hydration status. Instead, the brain must rely on some other cue to tell you to stop drinking and give you that instant feeling of refreshment.

Another group of researchers led by Yuki Oka at Caltech set out to tackle the problem of why we find drinking water so rewarding when were thirsty. Neuroscientists have long known that most reward signals are carried by a molecule called dopamine. In order to look at the role that this molecule has drinking behaviors, Okas team used a new kind of sensor that glows in the presence of dopamine. By putting this sensor into a mouses brain, they were able to record dopamine levels in real time as the mouse went about its tasks .

Figure 3: Drinking water is rewarding.

Michelle Frank is a PhD Candidate in Neurobiology at Harvard Medical School.

Jovana Andrejevic is a fourth-year Applied Physics Ph.D. student in the School of Engineering and Applied Sciences at Harvard University.

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S Of The Brain And Their Functions

Cerebrum

The cerebrum is the largest portion of the brain, and contains tools which are responsible for most of the brain’s function. It is divided into four sections: the temporal lobe, the occipital lobe, parietal lobe and frontal lobe. The cerebrum is divided into a right and left hemisphere which are connected by axons that relay messages from one to the other. This matter is made of nerve cells which carry signals between the organ and the nerve cells which run through the body.

Frontal Lobe: The frontal lobe is one of four lobes in the cerebral hemisphere. This lobe controls a several elements including creative thought, problem solving, intellect, judgment, behavior, attention, abstract thinking, physical reactions, muscle movements, coordinated movements, smell and personality.

Parietal Lobe:Located in the cerebral hemisphere, this lobe focuses on comprehension. Visual functions, language, reading, internal stimuli, tactile sensation and sensory comprehension will be monitored here.

Occipital Lobe: The optical lobe is located in the cerebral hemisphere in the back of the head. It helps to control vision.

  • Broca’s AreaThis area of the brain controls the facial neurons as well as the understanding of speech and language. It is located in the triangular and opercular section of the inferior frontal gyrus.

Cerebellum

Limbic System

Brain Stem

Hope this guide on parts of the brain and their functions help you understand the issue more clearly.

What Are The Parts Of The Nervous System

The nervous system is made up of the central nervous system and the peripheral nervous system:

  • The brain and the spinal cord are the central nervous system.
  • The nerves that go through the whole body make up the peripheral nervous system.

The human brain is incredibly compact, weighing just 3 pounds. It has many folds and grooves, though. These give it the added surface area needed for storing the body’s important information.

The spinal cord is a long bundle of nerve tissue about 18 inches long and 1/2-inch thick. It extends from the lower part of the brain down through spine. Along the way, nerves branch out to the entire body.

The brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by a set of ring-shaped bones called vertebrae. They’re both cushioned by layers of membranes called meninges and a special fluid called cerebrospinal fluid. This fluid helps protect the nerve tissue, keep it healthy, and remove waste products.

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S Of The Brain: Structures Anatomy And Functions

The human brain is one of the largest and most complex organs in the body. It controls your emotions, thoughts, speech, memory, creativity, breathes, movement, and stores information from the outside world. This article discusses the different parts of the brain and the function of each structure.

The brain is a 3-pound organ that contains more than 100 billion neurons and many specialized areas. There are 3 main parts of the brain include the cerebrum, cerebellum, and brain stem. The Cerebrum can also be divided into 4 lobes: frontal lobes, parietal lobes, temporal lobes, and occipital lobes. The brain stem consists of three major parts: Midbrain, Pons, and Medulla oblongata. Although each structure has a distinct function, they work together to control all functions of the body.

Can Baroreflex Also Present Confusing Signals For Thirst And Hunger

PPT

In 2008, our group discovered a novel neuropeptide encoded in the somatostatin preprohormone that when administered icv, unlike somatostatin, inhibited food and water intake in a significant and dose-dependent fashion . The antidipsogenic and anorexigenic action of this peptide, named neuronostatin, could be blocked by pretreatment with a melanocortin receptor antagonist, SHU9119. This suggested an interaction of neuronostatin with pro-opiomelanocortin producing neurons , something we established in collaboration with Alastair Fergusons assistance by electrophysiologic approaches . At that point, it appeared that the effects of neuronostatin on water intake might be mainly a reflection of its anorexigenic activity because not only were POMC neurons activated by the peptide, NPY producing neurons were also inhibited . But are those anorexigenic and antidipsogenic actions physiologically relevant? Because neuronostatin is a product of posttranslational processing of the somatostatin preprohormone, any attempt to compromise the peptides production would also compromise somatostatin production and thus the effects observed would be uninterpretable. In fact, the absence of an altered growth phenotype of, or growth hormone secretion in, somatostatin gene knockout animals proves this point .

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Neural Mechanisms Subserving Osmotically Stimulated Thirst

FIGURE 1. Diagram of the sagittal midline of the rat brain showing circulating factors that act on the various components of the lamina terminalis to influence thirst. The two parts of the lamina terminalis that lack a normal blood-brain barrier, the subfornical organ and organum vasculosum of the lamina terminalis , are shaded with vertical lines, whereas the other component of the lamina terminalis, the median preoptic nucleus is indicated by the spotted area. The part of the lamina terminalis that is included in the anteroventral third ventricle region is indicated by the white bracket. The interrupted white line indicates an inhibitory influence of atrial natriuretic peptide , whereas angiotensin II, relaxin, and hypertonicity have excitatory actions on the lamina terminalis. The question mark indicates that the efferent pathways from the lamina terminalis that mediate thirst are not yet known. oc, Optic chiasm ac, anterior commissure.

FIGURE 3. Pseudocolor images of positron emission tomography of subjects made thirsty by an intravenous infusion of hypertonic saline and then 3 min after thirst had been satiated by the drinking of water . Sagittal images of the left side of the brain 8 mm lateral to the midline show activations proceeding along the cingulate cortex from anterior to posterior parts in the thirsty subjects that were extinguished on slaking the thirst. Reproduced with permission from Ref. .

What Are The Symptoms Of Hypothalamus Dysfunction

Symptoms of hypothalamus dysfunction correspond to the types of hormone involved and if the hormone level is too low or too high. Some symptoms of a hypothalamus problem may include:

  • Frequent need to pee.

A note from Cleveland Clinic

Your brains hypothalamus is the smart control coordinating center of your body. Just like your homes smart control system automatically adjusts heat, cold, security and everything you need to have a successfully functioning home, so too does your hypothalamus serve in this same capacity in your body. It works directly on your autonomic system to seamlessly manage such functions as your heart rate, blood pressure and body temperature. It also works by releasing hormones that direct other hormones or other glands to manage other bodily functions like sleep, mood, muscle and bone growth and sexual drive. Many conditions can affect your hypothalamus, causing a wide range of health problems.

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Physiological Mechanisms Of Hunger And Eating

There are a number of physiological mechanisms that serve as the basis for hunger. When our stomachs are empty, they contract. Typically, a person then experiences hunger pangs. Chemical messages travel to the brain, and serve as a signal to initiate feeding behaviour. When our blood glucose levels drop, the pancreas and liver generate a number of chemical signals that induce hunger and thus initiate feeding behaviour.

For most people, once they have eaten, they feel satiation, or fullness and satisfaction, and their eating behaviour stops. Like the initiation of eating, satiation is also regulated by several physiological mechanisms. As blood glucose levels increase, the pancreas and liver send signals to shut off hunger and eating . The foods passage through the gastrointestinal tract also provides important satiety signals to the brain , and fat cells release leptin, a satiety hormone.

The various hunger and satiety signals that are involved in the regulation of eating are integrated in the brain. Research suggests that several areas of the hypothalamus and hindbrain are especially important sites where this integration occurs . Ultimately, activity in the brain determines whether or not we engage in feeding behaviour .

Figure EM.9 Hunger and eating are regulated by a complex interplay of hunger and satiety signals that are integrated in the brain

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