This is a sequence of animations broken into seven parts on the topic of Physiology of Hunger.

1. Part 1 of 7:
2. The on-screen text says "As you surely have noticed when your stomach growled loudly at an untimely moment, hunger is often accompanied by stomach contractions. Hence, one early theory of hunger was that stomach contractions cause hunger. However, this theory was soon discarded when research showed that people continue to experience hunger even after their stomachs have been removed out of medical necessity."
3. Part 2 of 7:
4. The on-screen text says "Research eventually suggested that the experience of hunger is controlled in the brain—specifically, in the hypothalamus. In research with rats, investigators used electrical stimulation of the brain and lesioning techniques to activate or destroy specific areas in the hypothalamus."
5. Part 3 of 7:
6. The on-screen text says "Based on these methods, researchers concluded that the lateral hypothalamus was the brain’s start center for hunger and that the ventromedial hypothalamus was the brain’s stop center for hunger. Eventually, a variety of research findings undermined the dual-centers model of hunger. The current thinking is that the lateral and ventromedial areas of the hypothalamus are elements in the neural circuitry regulating hunger, but not the key elements, nor simple on-off centers."
7. Part 4 of 7:
8. The on-screen text says "Today, scientists believe that two other areas of the hypothalamus—the arcuate nucleus and the paraventricular nucleus—play a larger role in governing hunger. Contemporary theories of hunger focus more on neural circuits that pass through areas of the hypothalamus rather than on anatomical centers in the brain."
9. Part 5 of 7:
10. The on-screen text says "Let's look at some other biological factors that contribute to the modulation of eating, such as digestive regulation. After you have eaten, the stomach can send signals to the brain that inhibit further eating. For instance, the vagus nerve carries information that indicates when the stomach is full. Other nerves carry messages about the nutrient contents of the stomach that inhibit hunger."
11. Part 6 of 7:
12. The on-screen text says "A variety of hormones circulating in the bloodstream also contribute to the regulation of hunger. For example, after the body goes without food for a while, the stomach secretes ghrelin, which causes stomach contractions and promotes hunger. In contrast, after food is consumed, the small intestine releases a hormone called CCK that delivers satiety signals to the brain, thus decreasing hunger."
13. Part 7 of 7:
14. The on-screen text says "A hormone called leptin contributes to the long-term regulation of hunger. Leptin is produced by fat cells throughout the body and released into the bloodstream, providing the hypothalamus with information about the body’s fat stores. When fat stores and leptin levels are high, the tendency to feel hungry diminishes. When fat stores and leptin levels are low, signals arriving in the brain promote increased hunger."
15. End of animated sequence.