![image](myerspel4e_fig_9_07.jpg)
FIGURE 9.7 The appetite hormones
• Ghrelin: Hormone secreted by empty stomach; sends “I’m hungry” signals to the brain.
• Insulin: Hormone secreted by pancreas; controls blood glucose.
• Leptin: Protein hormone secreted by fat cells; when abundant, causes brain to increase metabolism and decrease hunger.
• Orexin: Hunger-triggering hormone secreted by hypothalamus.
• PYY: Digestive tract hormone; sends “I’m not hungry” signals to the brain.