13 Appetite and Eating

Question 1

Set point theory

Answer 1

Hunger is a consequence of an energy deficit. The body seeks to return to an optimal level of energy (set point)

Question 2

Problems with set point theory

Answer 2

• Evolutionarily unlikely- we need to cope with inconsistent resources in the environment not just a system that responds to energy deficits.
• not supported by evidence. Drinking a high calorie drink doesn’t prevent hunger
• ignores environmental factors like the effect of learning, preference and social factors

Question 3

Positive incentive theory

Answer 3

• Anticipation, animals are driven to eat by the expected pleasure of eating.
• Craving, eating and the perception of hunger is initiated by craving.
• Multiple factors, flavour of food, knowledge of food, time since last meal

Question 4

How do animals choose what to eat?

Answer 4

They eat what is “good” for them (high in calories). They avoid food which makes them ill. They learn from watching what others eat. They can make associations between minerals and flavours

Question 5

What determines when we eat?

Answer 5

Signals for a meal (time, smells) evoke a cephalic phase. Insulin is released into the blood which decreases blood glucose.

Question 6

Ventralmedial

Answer 6

A satiety centre, part of the brain that was thought to prevent overeating

Question 7

VMH syndrome

Answer 7

A lesion in the ventralmedial which causes excessive eating and weight gain

Question 8

Lateral hypothalamus

Answer 8

A feeding centre. Lesion causes the cessation of eating

Question 9

LH syndrome

Answer 9

The cessation of eating and drinking

Question 10

Why might VMH syndrome and LH syndrome may not be accurate?

Answer 10

Other areas of the brain were also damaged when lesions were cut in VMH. Hypothalamus regulates metabolism not eating

Question 11

What is the stomachs role in hunger

Answer 11

It contracts when hungry but isn’t necessary for hunger since patients without stomachs have still experienced hunger. Satiety signal must be reached by bloodflow

Question 12

Peptides

Answer 12

Short chains of amino acids that can function as a hormone or neurotransmitter.

Question 13

How does CCK affect hunger?

Answer 13

May induce illness since it stops hungry rats from eating

Question 14

How does leptin affect hunger?

Answer 14

Higher leptin levels reduce appetite and weight