8. Appetite

Question 1

What is the first stage of digestion?

Answer 1

Oral cavity and salivary glands

Question 2

What is the importance of the oral cavity and saliva glands?

Answer 2

Chewing food and mixing with saliva

Question 3

What is the second stage of digestion?

Answer 3

Oesophagus

Question 4

What is the role of the oesophagus?

Answer 4

Transports food

Question 5

What is the third stage of digestion?

Answer 5

dunodenum & small intestine

Question 6

What is the role of the dunodenum and small intestine?

Answer 6

breaks food to amino acids and simple sugars which pass into the bloodstream to the liver

Question 7

What is the fourth stage of digestion?

Answer 7

Stomach

Question 8

What is the role of the stomach?

Answer 8

Storage, contains digestive enzymes and acids

Question 9

What is the fifth stage of digestion?

Answer 9

Liver and gallbladder

Question 10

What is the importance of the liver and gallbladder?

Answer 10

production and storage of bile, aids the digestion of fat

Question 11

What is the sixth stage of digestion?

Answer 11

Pancreas

Question 12

What is the role of the pancreas?

Answer 12

Produces and emits digestive enzymes into the small intestine

Question 13

What is the final stage of digestion?

Answer 13

Large intestine/ colon

Question 14

What is the role of the large intestine/colon?

Answer 14

absorb water and breakdown waste, to produce faeces

Question 15

How is energy stored in the body?

Answer 15

Fats, proteins and glycogen (stored in liver and muscles to be readily converted into glucose)

Question 16

What are the three phases of energy metabolism?

Answer 16

cephalic, absorption, fasting

Question 17

What is the cephalic phase?

Answer 17

preparing to eat

Question 18

What is the absorptive phase?

Answer 18

energy from a meal is absorbed into bloodstream to meet immediate energy needs

Question 19

What is the fasting phase?

Answer 19

Unstored energy from meal has been used and energy is withdrawn from stored to meet needs

Question 20

What is the role of insulin?

Answer 20

its a hormone that controls energy metabolism

Question 21

Where is insulin released?

Answer 21

By the pancreas during the cephalic and absorptive phases

Question 22

What happens when there are low levels of insulin?

Answer 22

promotes conversion of glycogen and protein to glucose

Question 23

What is the role of glycogen?

Answer 23

Promoting release of fatty acids from tissue to use as primary fuel and conversion to ketone used as an energy source by muscles

Question 24

What is homeostasis?

Answer 24

A stable environment
Energy intake - expenditure = ideal homeostatic system

Question 25

What is the set point?

Answer 25

The body's energy rescources are maintained at optimal levels

Question 26

What happens when energy falls below set point?

Answer 26

Hunger and eating

Question 27

What happens when energy returns to set point?

Answer 27

Satiety

Question 28

What is the glucostatic theory?

Answer 28

Eating is regulated by a system designed to maintain blood glucose set point (short-term regulation)

Question 29

What is the lipostatic theory?

Answer 29

There is a set point for body fat, deviations produce adjustments in eating that return levels of body fat to set point

Question 30

What is reward driven eating?

Answer 30

Humans and animals are not driven to eat by internal energy deficits, cues associated with food reward can trigger desire to eat

Question 31

How can classical conditioning be applied to eating behaviour?

Answer 31

Pavlov's dogs= hunger is triggered by expectation of food, not by an internal energy deficit

Question 32

What is hedonic hunger?

Answer 32

Human consumption is driven by pleasure, not by the need for calories e.g. a sweet treat

Question 33

What is sensory-specific satiety?

Answer 33

The decline of pleasantness of a food as it is eaten, relative to an uneaten food e.g. ratings of banana odour decreased after eating bananas

Question 34

What is the appetizer effect?

Answer 34

Consumption of a palatable food produces a small increase in hunger, early in the meal- relative to a bland food

Question 35

What are three factors that have the biggest impact on obesity?

Answer 35

Availability of sugary drinks, large portion sizes, food promotions and advertising

Question 36

What is a negative feedback system?

Answer 36

feedback from changes in one direction, elicit changes in the opposite direction

Question 37

What is leptin?

Answer 37

Could be a gene linked to obesity

Question 38

What happened in the mice study with leptin?

Answer 38

Mice who had the gene developed severe obesity, they ate more and converted calories to fat more efficiently, blood from the thin mice reduced the weight of the obese mice

Question 39

What is congenital leptin deficiency?

Answer 39

Rare condition where due to a gene deficit, leptin cannot be produced- children demonstrate excessive weight gain

Question 40

Is body weight heritable?

Answer 40

Family and twin studies suggest 47-90% heritability

Question 41

How does the genetic risk operate?

Answer 41

Via the neurobiology controlling appetite regulation and a tendency to overeat when prompted

Question 42

What happens when participants had the FTO gene?

Answer 42

higher levels of ghrelin (hunger hormone), felt hungry after eating, had different brain responses to food, consumed more fat and energy

Question 43

What is the thrifty genes? (Neel, 1962)

Answer 43

Gene that promotes storage of energy as fat during periods where food was abundant, families with this gene would have a survival advantage but they are counter-productive in a modern feast environment