The hypothalamus has important roles in the regulation and control of hunger. However, there are many other genetic and environmental factors that also contribute to the sensation of hunger. In order to understand the role of the hypothalamus in hunger, one must first understand the complexity of the hypothalamus.
The Hypothalamus: What is it?
The hypothalamus is a highly complex region in the brain that efficiently links the nervous system to the endocrine system through the use of the pituitary gland. Roughly the size of an almond, it is located just superior (above) to the brain stem.
The nervous system functions through electrochemical signaling through a complex specialized network of neurons. The endocrine system is an integrated system of many organs responsible for the production and secretion of hormones that regulate cell signaling.
The Hypothalamus: What does it do?
The hypothalamus is responsible for a variety of biological functions within your body. The hypothalamus is the body's main regulator of homeostasis. The homeostasis of your body is critical. Homeostasis is defined as the production and maintenance of a stable internal environment. Some of the homeostatic mechanism that the hypothalamus controls is listed below.
- Blood pressure
- Body temperature
- Circadian rhythm
- Heart rate
- Immune responses
- Sexual desire
- Water balance
Brain Function: A General Overview
The brain mainly functions by use of neurotransmitters. The four most recognized neurotransmitters include serotonin, acetylcholine, epinephrine and norepinephrine. These neurotransmitters are regulated by neuromodulators and hormones. The entire nervous system is effectively connected and communicated by the use of neurotransmitters. The hypothalamus is responsible for the production and secretion of particular neurohormones.
The Hypothalamus: How does it Function?
The hypothalamus completes is necessary functions by the production and secretion of a variety of hormones, all responsible for particular reactions. These hormones complete various reactions, particularly through stimulation or inhibition of certain neurotransmitters.
The Hypothalamus and Hunger: The Connections
The hypothalamus has three main regions that have been scientifically associated with hunger, including the lateral, ventromedial, and paraventricular hypothalamus. These regions have been correlated with receptors for certain chemical messengers that signal hunger. The two main chemical messengers include ghrelin and leptin.
- Lateral Hypothalamus: This region of the brain is associated with hunger recognition.
- Ventromedial Hypothalamus: This nuclear region is involved with the recognition of the feeling of fullness.
- Paraventricular Hypothalamus: This nuclear region is involved with the regulation of hunger.
Chemical Hunger: Ghrelin
The hormone ghrelin is produced by the stomach and the hypothalamus. Hormonal levels of ghrelin have been shown to increase before meals and decrease after. Ghrelin was the first discovered hunger hormone. The hypothalamus has receptors for ghrelin, which signals the body of hunger. Ghrelin has also been associated with certain aspects of certain addictive drugs, alcohol, and is associated with food cravings as a reward.
Chemical Hunger: Leptin
The hormone leptin is produced by adipose (fat) tissue, and binds to certain receptors of the hypothalamus. Leptin works oppositely of ghrelin, and signals the body that it is full. Leptin also has specific roles in the regulation of energy expenditure and intake.