Eating Behaviours

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Neural and Hormonal explanations for Eating Behaviour

Homeostasis: the body's ability to regulate things like temperature and glucose to sustain ourselves.

Neural Explanation:

1. The Lateral Hypothalamus-

When glucose levels fall the glucostatic receptors in the blood take a message to the lateral hypothalamus

Neurons fire= feeling hungry= search for food= glucose levels rise= no longer hungry

- Role of Ghrelin

Secreted by the stomach

a hormonal marker which tells us when we last ate, related to how empty our stomach is

More Ghrelin is released the longer we go without food

detected by receptors in the part of the hypothalamus called the arcuate nucleus

When Ghrelin levels get to a certain point, arcuate nucleus sends signals to the LH to secrete neuropeptide Y (a neurotransmitter associated with hunger)

2. The Ventromedial Hypothalamus-

Part of the Hypothalamus believed to be the 'off switch'

Activated by the rise in glucose levels in the blood, leading to a feeling of satiation which stops further eating

Electrical stimulation of VMH which causes desire to stop eating

-Role of Leptin

Hormone made by fat cells

Leptin levels in blood increase with fat levels detected in the brain by VMH (contributes to the VMH satiety mechanism

When levels reach certain point, individual feels full

Lincinio et al (2004) studied condition where people are unable to naturally produce leptin- lead to severe obesity

Treatment involved leptin replacement therapy- over 18 months average weight loss more than 40%, 49% reduction in food intake