What is Hunger? Hunger is a feeling of discomfort or weakness caused by lack of food along with the desire to eat. The part of the brain that controls hunger is the hypothalamus, the hypothalamus is a portion of the brain that contains a number of small nuclei with many different functions. They hypothalamus is below the thalamus, above the brainstem and is also part of the limbic system. This part of the brain controls body temperature, hunger, thirst, fatigue, sleep, and circadian rhythms. The hypothalamus is a brain structure made up of distinct nuclei. Their are three regions of the hypothalamic nuclei: anterior, tuberal, posterior. In these regions their are different areas that have different nucleus and each nucleus have a different function. The hypothalamus is highly interconnected with other parts of the central nervous system.
Anterior: The anterior has three areas Preoptic: Preoptic Nucleus Medial: Medial preoptic nucleus
Supraoptic Nucleus Paraventricular Nucleus Anterior Hypothalamic Nucleus Suprachiasmatic Nucleus Lateral: Lateral Nucleus Tuberal: The Tuberal has two areas Medial: Dorsomedial Hypothalamic Nucleus Ventromedial Nucleus Arcuate Nucleus Lateral: Lateral Nucleus Lateral Tuberal Nuclei Posterior: The posterior has two areas Medial: Mammillary Nuclei Posterior Nucleus Lateral: Lateral Nucleus Tuberomammillary Nucleus
The Stages Of Hunger When your body is hungry for an extended of time it enters a thing called starvation mode. Starvation mode involves a decreased metabolism in order to conserve energy. Six hours after eating: After we eat our bodies breakdown glycogen which are molecules that store energy. This process produces glucose which is a molecule that is used as big source of energy and is absorbed into the bloodstream. Six days of eating no food (three days of eating no food): Glucose stores last up to 24-48 hours but most of the time they are done after six hours. After glucose stores are depleted your body will enter a state of ketosis. Ketosis involves elevated levels of ketone bodies in your system. Ketone bodies are made from fatty acids when liver glycogen is entirely depleted and are then used for energy. Eating nothing for more than 72 hours: After seventy hours of no eating what happens is a stage called autophagy. Autophagy is when the fats are broken down your body then proceeds to break down the proteins in muscles, basically wasting away your muscle.
Hunger Scale in Seven Stages 1. Starving- An uncomfortable and empty feeling with a kind of light-headedness or jitteriness which is caused by low blood sugar levels from lack of food. 2.Hungry- An alarm telling you that it is time for you to eat. If you don't eat with in an hour you will enter the starving stage. 3.Moderately Hungry- Similar to the hungry stage but with more alarm type things such as a growling stomach. 4.False Hunger- Seems like hunger but is actually connected with other biological and psychological problems. 5.Satisfied- Not being hungry and or full, no more things such as a growling stomach. 6.Full- You may be tempted to eat more. 7.Overstuffed- You eat a lot more than needed and you may feel uncomfortable. You may even have some burning sensation due to the stomach acids creeping back into your esophagus.
Key People
Boldyreff- Studied extensively on the empty stomach in mammals. He would preform most of his studies on dogs, using balloons on them as well to test their hunger. He used the dogs to follow and study the different stages of hunger.
Washburn- Was the main performer to the balloon experiment, he trained himself to swallow a balloon with a tube attached to it, then the balloon would be inflated inside of his stomach. Washburn studies the movements of the empty stomach, called gastric hunger contractions.
Abraham Maslow- Created the hierarchy of needs. It this case hunger is a need that must be satisfied. His theory of psychological health predicted on fulfilling innate human needs in priority, culminating in self-actualization. Maslow suggested that a person who is cold sick of hungry may not be as interested in socializing, learning, or working, no matter the gain.
Albert Stunkard- Professor of Psychiatry at Perelman School of Medecine at the University of Pennsylvania. He studied genetic and evnviromental influences on human obesity. He also came up with binge-eating and questioned "facts" that no one had questioned before.
Key Terms
Hypothalamus- The area of the brain that secretes substances that influence pituitary and other gland function and is involved in the control of body temperature, hunger, thirst, and other processes that regulate body equilibrium.
Nuclei- The number of protons in the nucleus determines the atoms atomic number and its position in the Periodic Table.
Thalamus- Two gray masses of matter lying between the cerebral hemispheres on either side of the third ventricle, relaying sensory information and acting as a center for pain perception. The Limbic System- A complex system of nerves and networks in the brain, involving several areas near the edge of the cortex concerned with instinct and mood. It controls the basic emotions such as fear, pleasure, and anger. It also drives the need for hunger, sex, dominance, and care of offspring.
Lateral Hypothalamus- The Lateral Hypothalamus is a part of the hypothalamus gland and is the portion that controls hunger. Damage to this area can cause reduced food intake, presumably through loss of appetite, and stimulation of this area can increase appetite. Studies indicate that the lateral hypothalamus influences glucose metabolism and through the body's inclination towards homeostasis can increase or decrease blood sugar levels through insulin secretion to increase or decrease appetite.
Ventromedial Hypothalamus- Known as the Ventromedial Nucleus is located inside the hypothalamus. It is known as a nucleus because it is a distinct grouping of neurons within the hypothalamus. The ventromedial nucleus is responsible for the feeling of satiation, or fullness after eating, in organisms. It tells us when we have eaten enough and to stop eating.
Set Point Theory- states everyone's body has a genetically determined range of weight and temperature that their body will try to maintain to stay at optimal health. External- Motivated to eat by external cues, like stress, smell, or simply having food in front of you.
Internal- Motivated to eat by internal cues like an empty stomach or feelings of hunger.
Experiments
Albert Stunkard came a cross a girl who ate no breakfast but progressively ate more throughout the day then gorged herself at night. He called it "night eating syndrome" but eventually realized it wasn't real and called it binge eating. Nothing added up when he did studied people so he thought about everything. Eventually he redid Cannon & Washburn's experiment (balloon in stomach) and discovered that they were completely wrong. After studying people he realized that obese people didn't eat as often as others. He then came to the conclusion that obese people didn't know their internal cues that told them they were hungry. Instead, they were motivated to eat by external factors such as how close it was to dinner time.