Eating Behaviour – Neural Mechanisms In Involved In Controlling Eating Behaviour

Front 1

AO1 Homeostasis

Back 1

Body has developed various processes to ensure optimal functioning

Homeostasis – constant level of functioning. Signals for hunger and to stop overeating.

Front 2

A02 Homeostasis

Back 2

Cannon et al.
Insert a balloon in persons stomach.
Measured the contractions in the stomach when empty and found it illustrated hunger.

Front 3

A03 Cannon

Back 3

People without a stomach, possibly due to cancer and removal, they could still experience hunger and the association.

Front 4

AO1 Leptin

Back 4

Number of fat cells are dictated by diet in early years then body uses homeostasis to maintain these fat levels.

Fat cells release leptin (hormone) to indicate we have enough fat reserves

Appetite stays constant and they do not lose weight, so they become obese

Human’s leptin deficiency means obesity is more prevalent

Front 5

AO1 Hypothalamus

Back 5

Detects whether we are hungry or full

Ventromedial hypothalamus used.

If damaged in rats, they are not able to stop eating

Neurotransmitter NPY stimulates lateral hypothalamus which causes perceived hunger.

Low glucose levels also stimulate the lateral hypothalamus causing more eating

High glucose levels also stimulate the ventromedial hypothalamus causing more eating

Front 6

AO1 Ghrelin

Back 6

Hormone from empty stomach signals hypothalamus to stimulate feeding

Amount released proportional to emptiness of stomach

High amount of ghrelin makes person hungry and low amount makes them full

Front 7

AO2 Ghrelin

Back 7

Cummings et al. studied changes in blood ghrelin levels between meals.

Ppts assessed their degree of hunger every 30 minutes.

Findings were that ghrelin levels fell immediately after eating lunch, reaching their lowest level at about 70 minutes.

In 5ppts ghrelin levels were closely correlated with the degree of hunger reported by the ppts.

Concluded that ghrelin levels directly reflect stomach emptiness and are closely related to subjective feelings of hunger.

Front 8

AO3 Cummings

Back 8

There were only six participants. All were male.

Data was correlational, so we cannot say that ghrelin causes feelings of hunger.
Cant assume cause and effect

Front 9

IDA

Back 9

Real world apps – combating obesity and anorexia with this information

Nature vs. nurture – native Indians no obesity yet us has lot of obesity. Leptin = obesity in genes or deterministic.

Ethical issues – involved inserting a catheter into the pps veins so that blood samples could be collected.