Feeding and appetite (2)

Question 1

Define hunger.

Answer 1

The physiological process of feeling hunger (stomach growling etc.).

Question 2

Define appetite.

Answer 2

the psychosocial feeling of hunger “simply the desire to eat”.

Question 3

Define satiation.

Answer 3

The state when the stomach is satisfied and a person stops eating.

Question 4

Define satiety.

Answer 4

The feeling between your last immediate meal and the next (satisfaction/fullness).

Question 5

Describe digestion.

Answer 5

Digestion is the process by which these food stuffs are broken down into these simple molecules so that they can be utilised by the body. Digestion begins in the mouth.

Question 6

What is one use of fats?

Answer 6

They are used as an energy source.

Question 7

What are the three key macronutrients and what are they broken down into?

Answer 7

1. Protein – essential amino acids.
2. Carbohydrates – glucose.
3. Fat – lipid fat.

Question 8

Describe the relationship between chewing and hunger. (2)

Answer 8

• Chewing is evolutionary to allow primates/humans to consume hard, uneatable, foods.
• It plays a very minor role in hunger and satiety.

Question 9

Why is it important to have taste? (2)

Answer 9

• To check if food is spoiled or off.
• To make sure we are getting the correct range of nutrients.

Question 10

What are the five tastes?

Answer 10

1. Sweet.
2. Sour.
3. Salty.
4. Bitter.
5. Umami.

Question 11

How do hunger pangs work?

Answer 11

Hunger pangs are accompanied by stomach contractions. These are caused by chemo-stretch receptors.

Question 12

What is the process in the body telling the brain it is full?

Answer 12

• The gastric receptors around the stomach respond to being “stretched”.
• This then heads back to the brain, via the vagus nerve, to the medulla and then the hypothalamus.

Question 13

What is the hormone released in fullness/satiety?

Answer 13

A peptide hormone called Cholecystokinin (CCK).

Question 14

What are the three set points models? And where are they stored?

Answer 14

1. Insulin - stored in the pancreas.
2. Ghrelin - stored in the stomach.
3. Leptin - adipose tissue.

Question 15

What are the five stages of insulin release?

Answer 15

1. Hunger.
2. Eating food.
3. Body releases insulin to store excess glucose.
4. Hunger, glucose and insulin levels decline.
5. Pancreas releases glucagon slowing return of hunger.

Question 16

Describe the set points process of ghrelin.

Answer 16

In the lateral hypothalamus, Ghrelin will trigger increased hunger via elevated amounts of orexins and Neuropeptide Y (NPY).

Question 17

What does NPY do?

Answer 17

Blocks the satiety actions within the hypothalamus along with GABA.

Question 18

What does orexin do?

Answer 18

Support the motivation to eat.

Question 19

Describe the set points process of leptin.

Answer 19

• Leptin signals to several hypothalamic nuclei about fat reserves.

Question 20

What do high and low levels of fat suggest?

Answer 20

• High levels of fat indicate amble nutrition and therefore the body will desire to eat less.
• Low levels of fat indicate low levels of nutrition and therefore the body will indicate starvation and energy saving.

Question 21

What are the two key areas of the hypothalamus?

Answer 21

1. Ventromedial hypothalamus.
2. Lateral hypothalamus.

Question 22

Describe features of the ventromedial hypothalamus.

Answer 22

• The satiety centre.
• Lesions = hyperphagia (overeating).
• Stimulation = aphagia (undereating).

Question 23

Describe features of the lateral hypothalamus.

Answer 23

• The hunger centre.
• Lesions = aphagia (undereating).
• Stimulation = hyperphagia (overeating).

Question 24

Name four psychological factors that effect eating habits.

Answer 24

1. Taste.
2. Habit and learned behaviour.
3. Motivated food choice.
4. Food halo.

Question 25

What is the gut-brain axis?

Answer 25

A bidirectional communication network in which cognitions and mental states can influence gastrointestinal processes and vice versa.

Question 26

What is one effect of the gut-brain axis?

Answer 26

A “negative feedback loop” where individuals experiencing unpleasant emotions are more likely to eat higher amounts of refined sugar or other energy dense foods.