Control of food intake

Question 1

What starts to expand when you eat?

Answer 1

→ The fundic area expands to accomodate food

Question 2

What two hormones are used in accommodation?

Answer 2

→ VIP and NO

Question 3

What is PYY and what does it do?

Answer 3

→ Is is a satiety factor and increases gut motility

Question 4

What do you feel when emptying occurs?

Answer 4

→ A sense of hunger (ghrelin)

Question 5

Where do contractions occur and what are they mediated by?

Answer 5

→ Occur in the antrum

→ Mediated by AcH

Question 6

What relaxation occurs when food is swallowed?

Answer 6

→ Receptive relaxation

Question 7

What is receptive relaxation done by?

Answer 7

→ Vagal innervation

Question 8

What kind of relaxation occurs in the stomach to allow accommodation?

Answer 8

→ adaptive relaxation

Question 9

What is CCK stimulated by?

Answer 9

→ Lipids

Question 10

What is affected if you cut vagus nerves?

Answer 10

→ Accommodation

→ Gastric compliance

Question 11

What is the difference between appetite and hunger?

Answer 11

→ Appetite is a psychological desire

→ Hunger is a physiological craving

Question 12

What is hyperphagia/polyphagia?

Answer 12

→ Abnormal desire for food

Question 13

What does the hypothalamus control?

Answer 13

→ Hunger + thirst

Question 14

Functions of the prefrontal cortex

Answer 14

→ Food seeking
→ Integration of sensory information from inside and outside the body
→ Receives emotional + cognitive information from the limbic system
→ Makes choices by translating the homeostatic and environmental information into adaptive behavioral responses,

Question 15

What is the limbic system?

Answer 15

→ Complex system of nerves and networks in the brain

associated with instinct and mood

Question 16

What sites is feeding behavior modulated by?

Answer 16

→ Lateral hypothalamus

→ Ventromedial hypothalamus

Question 17

What is the role of the lateral hypothalamus?

Answer 17

→Hunger + thirst center

Question 18

What is the role of the ventromedial nucleus ?

Answer 18

→ Satiety center

Question 19

What happens if there is a lesion to the VMN?

Answer 19

→ Increased appetite with weight gain

Question 20

What does the dorsomedial nucleus do?

Answer 20

→ Modulates energy intake (hunger center)

Question 21

What acts on the dorsomedial nucleus to increase feeding?

Answer 21

→ NPY into the DMN increases feeding

Question 22

What does the paraventricular nucleus do?

Answer 22

→ Modulates feeding behavior

Question 23

What does the arcuate nucleus produce?

Answer 23

→ Orexigenic signals

Question 24

What are the functions of the suprachiasmatic nucleus?

Answer 24

→ Human body clock is here
→Perception of the light-dark cycle
→ Sensation of hunger

Question 25

What is the ligand of the medial amygdaloid nucleus?

Answer 25

→ 5-HT | → Regulates appetite and food intake

Question 26

What are agents that reduce appetite called?

Answer 26

→ Anorexigenic factors

Question 27

When are carbohydrates and fats metabolized?

Answer 27

→ Carbohydrates during the day | → Fats during the night

Question 28

What condition happens if you stimulate the hypothalamus?

Answer 28

→ Aphagia

Question 29

What condition happens if there are lesions to the hypothalamus?

Answer 29

→ Hyperphagia

Question 30

What do opioids and growth releasing hormone do to appetite?

Answer 30

→ Increased appetite

Question 31

What does naltrexone do?

Answer 31

→ Reduce the hedonic valence of food

Question 32

What do orexigenic and anorexigenic neurotransmitters do?

Answer 32

→ orexigenic = increase appetite | → Anorexigenic = decrease appetite

Question 33

What does glucose in the blood stimulate?

Answer 33

→ Gluco-receptors in the hypothalamus

Question 34

What happens to hunger/appetite when blood glucose increases?

Answer 34

→Up regulation of satiety

Question 35

What happens to hunger/appetite when blood glucose decreases?

Answer 35

→ Up regulation of hunger

Question 36

What is the effect of temperature on appetite?

Answer 36

→Hot enivronments stimulate feeding

Question 37

What are the afferent inputs that affect appetite?

Answer 37

→Distension of a full stomach inhibits appetite →Contraction of an empty stomach stimulates appetite →Deposition of fat may control appetite

Question 38

What hormone is released when fat is ingested and what effect does this have?

Answer 38

→ CCK | → Slows gastric emptying

Question 39

What does CCK do?

Answer 39

→ Inhibits further food intake

Question 40

What happens if CCK is injected in the brain?

Answer 40

→ Appetite is reduced

Question 41

What does insulin release?

Answer 41

→ Adipokine

Question 42

What are the two effects that occur when insulin reaches the arcuate nucleus?

Answer 42

→ Stimulates arcuate nucleus → Catabolic effect reduces food intake and body fat →reduces NpY and AgRP → Over time there are anabolic effects which increase food intake and body fat

Question 43

What is the role of glucagon on controlling food intake?

Answer 43

→Acts mainly at the liver where it increases glucose production →while generating a signal to reduce energy intake that is relayed to the hindbrain.

Question 44

What is the role of insulin on controlling food intake?

Answer 44

→Insulin: acts at both the liver and the forebrain to reduce energy intake. → Suppress hepatic glucose production.

Question 45

What is the role of amylin on controlling food intake?

Answer 45

→acts directly at the hindbrain to reduce energy intake.

Question 46

What are the three pancreatic hormones?

Answer 46

→ Glucagon → Insulin → Amylin

Question 47

What does white adipose tissue secrete?

Answer 47

→ Leptin

Question 48

How does leptin control fat stores?

Answer 48

→ Operates a feedback mechanism between adipose tissue and the brain → Increases the expression of anorexigenic factors → Stimulates metabolic rate → Inhibits neuropeptide Y which stimulates feeding

Question 49

What is ghrelin?

Answer 49

→ Appetite inducing hormone - orexin → Fast acting and stimulates food intake → Increases central orexins - NPY and AgRP → Suppresses the ability of leptin to stimulate anorexigenic factors

Question 50

Where is ghrelin released from?

Answer 50

→ Stomach, pancreas and adrenals in response to nutritional status

Question 51

When do circulating ghrelin levels increase?

Answer 51

→ preprandially

Question 52

When do circulating ghrelin levels decrease?

Answer 52

→ after a meal

Question 53

What can secretion of ghrelin be inhibited by?

Answer 53

→ Leptin

Question 54

Where is obestatin produced?

Answer 54

→ The epithelial cells of the stomach

Question 55

What is obestatin encoded by?

Answer 55

→ The ghrelin gene

Question 56

WHat does obestatin do?

Answer 56

→ Antagonizes ghrelin induced food intake → Imbalance of ghrelin and obestatin may have a role in obesity → Suppresses food intake

Question 57

What is satiation of feeding associated with?

Answer 57

→motor planning and execution

Question 58

Why can we not modulate mechanisms of reward?

Answer 58

→ Cortico-limbic mechanisms of reward are under executive control so we cannot modulate it