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Chapter 10

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					    Chapter 10
Internal Regulation
                    Hunger


• Animals vary in their strategies of eating, but
  humans tend to eat more than they need at
  the given moment.

• A combination of learned and unlearned
  factors contribute to hunger.
                   Hunger


• The digestive system
• Saliva → carbs
• Stomach
   – Hydrochloric acid → proteins
• Small intestine
• Large intestine
                   Hunger


• The brain regulates eating through messages
  from the mouth, stomach, intestines, fat cells
  and elsewhere.
                   Hunger


• The main signal to stop eating is the
  distention of the stomach.

  – The vagus nerve

  – The splanchnic nerves
                  Hunger


• Duodenum



• Cholecystokinin (CCK)
                   Hunger


• Glucose, insulin, and glucagon levels also
  influence feelings of hunger (see figures 10-
  14, 10-15, 10-6).




• Diabetes
Fig. 10-14, p. 311
Fig. 10-15, p. 311
Fig. 10-16, p. 311
                    Hunger


• Long-term hunger regulation is accomplished
  via the monitoring of fat supplies by the body.



• Leptin
                   Hunger


• Information from all parts of the body
  regarding hunger impinge into two kinds of
  cells in the arcuate nucleus.
                   Hunger


• Output from the arcuate nucleus goes to the
  paraventricular nucleus of the hypothalamus.
                    Hunger


• Input from the hunger-sensitive neurons of
  the arcuate nucleus is inhibitory to both the
  paraventricular nucleus and the satiety-
  sensitive cells of the arcuate nucleus itself.
                   Hunger


• Output from the paraventricular nucleus acts
  on the lateral hypothalamus.
   – The lateral hypothalamus controls insulin
     secretion and alters taste responsiveness.
• Animals with damage to this area refuse food
  and water and may starve to death unless
  force fed.
Fig. 10-20, p. 315
                   Hunger


• The lateral hypothalamus contributes to
  feeding
Fig. 10-22, p. 316
                 Hunger


• Ventromedial hypothalamus → satiety
                  Hunger


• People with a mutated gene for the receptors
  melanocortin overeat and become obese.
  – Melanocortin is a neuropeptide responsible
    for hunger.
• Prader-Willis syndrome
                    Hunger


• Anorexia nervosa



• Bulimia nervosa



• Overeating and Binge-eating Disorder

				
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