Neural Mechanisms Controlling Eating Behaviour Flashcards
Ventromedial Hypothalamus (VMH)
The satiety centre - inhibits feeding
Anand and Brobeck 1951
Found that a lesion to the lateral hypothalamus causes aphagia in rats, concluded it was the feeding centre.
Lateral Hypothalamus (LH)
The feeding centre - stimulates feeding
Ghrelin
A hormone that is secreted from the stomach.
Released when the stomach is empty.
Sends signals to stimulate feelings of hunger.
Where is ghrelin secreted from?
The stomach
Which hormone signals you are hungry?
Ghrelin
Cummings et al. 2004 procedure
6 participants
Ate lunch
Ghrelin levels measured through blood samples taken every 5 minutes
Assessed their levels of hunger every 30 minutes
What did Cummings et al. 2004 find?
Blood ghrelin levels fell immediately after eating, then slowly began to rise and peaked when participants requested their evening meal.
Ghrelin levels also closely correlated with the degree of hunger reported by 5 out of the 6 participants.
Cummings et al. 2004 evaluation
Extraneous variables such as time and context cues eliminated
Small sample size
Androcentric
Correlation not causation
Physical and psychological harm - but informed consent given.
Which study investigated the changes in blood ghrelin levels over time between meals?
Cummings et al. 2004
Where is CCK released from?
The duodenum
What does CCK do?
CCK sends satiety signals to the hypothalamus in the presence of food to inhibit feeding.
Glucostat theory
Suggests glucose levels are a key signal of satiety and hunger.
However, it has been found that the levels aren’t significant enough, and although diabetics have high levels of glucose, they still have normal appetites.
What is the main short-term factor which inhibits the intake of food?
CCK being released from the duodenum when food is present
What is leptin?
A hormone that is released from adipocytes to indicate body weight.
When there is more body fat, more leptin is released and the hypothalamus reduces feeding.
Which hormone indicates body fat?
Leptin
Which hormone inhibits feeding?
CCK
Which hormone stimulates feeding?
Ghrelin
Evaluate the biological explanation of eating behaviour.
Reductionist - only takes into account biological factors, ignores other factors such as environmental and social cues - for example, de Castro (2004) found that people eat more in the company of others.
Research is mostly done on non-human animals - this is unethical and also can’t be generalised to humans.
Which part of the hypothalamus stimulates feeding?
Lateral hypothalamus (LH)
Which part of the hypothalamus inhibits feeding?
Ventromedial hypothalamus (VMH)
Who found that people eat more in the company of others?
De Castro (2004)
De Castro (2004) What did they find and how would you use this in an essay?
They found that people eat more in the presence of others.
You would use this to evaluate the biological explanation of eating behaviour in and essay.
Hetherington and Ranson 1942
Found that a lesion to the ventromedial hypothalamus caused over eating in rats, concluded the VMH is the satiety centre.
Who concluded that the LH is the feeding centre?
Anand and Brobeck 1951
Who concluded that the VMH is the satiety centre?
Hetherington and Ranson 1942
