H. Hunger, Eating, and Health - Part 2

Question 1

Describe 2 types of environmental stim that can influence eating

Answer 1

1. sensory stim = smelling/seeing food
2. social stim = when sitting at a table or w/ friends

Question 2

a) describe pre-meal hunger
b) what are the 2 theories used to cause this?

Answer 2

a) the hunger that one feels right before a meal
b)
- set pt = you feel hungry when you are calorie deficient
- positive-incentive = you feel hungry as a result of the anticipation of eating itself (ie flavour of food)

Question 3

describe an experiment that proves that pre-meal hunger can be conditioned (phase 1, 2, + conclu)

Answer 3

phase 1 = provide specifically timed meals for rats. While they are given the food a light and buzzer play
phase 2 = now make the food readily available all the time. If you play the light and the buzzer the rats immediately go and eat the food despite having been regularly eating the whole day.
Conclusion = the light + buzzer were paired the food being given thus they were played they made the rats feel hungry in preparation for an upcoming meal (pre-meal hunger)

Question 4

What are the 2 kinds of hunger stimulations? - 4

Answer 4

1. hypoglycemia = low levels of glucose in the blood
2. low lipid levels in blood = low FAs

Question 5

Match the following terms to Glucose or Fats
a) hypoglycemia
b) lipoprivation
c) glucoprivic hunger
d) low lipids/FAs
e) lipoprivic hunger
f) glucoprivation

Answer 5

Glucose = a, f, c
Fats = d, b, e

Question 6

a) What are the 2 parts of the body that are considered hunger stimulation detectors?
b) what type of hunger stimulation is it sensitive to?

Answer 6

1. brain = sensitive to glucoprivation (glucose)
2. liver = glucoprivation + lipoprivation (glucose + lipids)

Question 7

T or F - glucoprivation and lipoprivation triggers hunger due to the body being deficient in these major macromolecules

Answer 7

F - these stimulations are just that there is a low level of glucose/FAs in the blood but there is still plenty that can be resorbed through the liver/adipose tissue

Question 8

Describe the fxn of the satiety signal

Answer 8

a signal that results in use feeling full

Question 9

Wrt the sham rat study
a) What was the purpose?
b) how did they test this?
c) What were the 2 groups involved?
d) what were the results found for each group?
e) What was the conclusion for this exp?

Answer 9

a) to see if nutrient density impact how much we eat
b) They cut the esophagus from the stomach thus everything that the rats ate would never reach the stomach
c) Sham rats eating unfamiliar food + sham rats eating familiar food
d) the rats that ate the familiar food did not change eat more at first but then INC what they ate over time. Whiles the rats that ate the unfamiliar food ate more right from the beginning.
e) The familiarity of the diet drives how much we eat more so than the nutritional density.

Question 10

Describe the 3 factors that influence how much we eat

Answer 10

1. serving size = bigger portions lead to eating more
2. appetizer effect = eating smaller portions of food increase hunger by activating the cephalic phase
3. social influences = the presence of ppl has a huge influence on how much we eat (sometimes more sometime less)

Question 11

a) Which factor relates to the cafeteria diet? - 1
b) What is the cafeteria diet? - 1
c) does it result in eating more or less? why? - 2

Answer 11

a) the appetizer effect
b) the idea of having a variety of foods available all at once
c) the more variety of foods available results in more eating b/c we will not get bored of the flavor as there are more options. As opposed to eating one type of food w/ one flavour

Question 12

a) Describe sensory-specific satiety? - 1
b) why do we have this?

Answer 12

a) the act of getting bored of a flavour that you are experiencing right now causing you to be satiated (reduced incentive value) for that specific food that contains that flavour
b) an evolutionary adaptation to encourage the intake of differ foods in order to get more nutrients

Question 13

T or F - the sensory-specific satiety states that eating one type of food results in an INC of incentive value of that food as it triggers the appetizer effect

Answer 13

F - you get bored of the flavour and thus have an INC incentive value for other types of foods instead

Question 14

T or F - satiety signals only relate to factors that influence how much you eat

Answer 14

F - they also relate to factors that influence what and when you eat

Question 15

What are the 3 pieces of evidence that show that intention to eat triggers a decline in blood glucose?

Answer 15

1. right b/f eating blood glucose levels DEC
2. the act of removing blood glucose does not stop one from eating
3. if you skip a meal the blood glucose levels will rise back up

Question 16

T or F - blood glucose levels in the brain will only DEC right before a meal in order to compensate for the flood of glucose that is about to enter the bloodstream

Answer 16

F - the glucose levels in the brain remain constant

Question 17

Describe the following types of satiety signals
a) short-term
b) long-term

Answer 17

a) immideatly stop eating due to feeling full
b) regulation of eating over a long period of time

Question 18

Label this diagram according to the colours shown

Answer 18

yellow = esophagus
green = liver
blue = stomach
pink = duodenum
orange = small intestine
purple = large intestine
red= rectum

Question 19

Short-term satiety signals have 4 factors what are they?

Answer 19

1. psychological = learning
2. gastric = stomach
3. duodenum
4. liver

Question 20

long-term satiety signals has a tissue that influences it what is it?

Answer 20

adipose tissue

Question 21

There was an experiment where they had one experiment ingest a ballon and attach it to a tube of water.
a) what were they testing?
b) what did they find?
c) is this involved w/ short or long-term satiety signals?
d) what proved this theory false?

Answer 21

a) to see if the volume of the stomach is what triggered being hungry/full
b) he reported being hungry when the stomach was contracted (small volume). Thus it was concluded that the volume of the stomach stimulates satiety
c) short
d) the fact that patients that didn’t have a stomach would still report feeling hungry

Question 22

There was an experiment in which a rat underwent a transplant of a second stomach.
a) what was the purpose of this exp?
b) what were the results?
c) what did this show?
d) does this involve short or long term satiety signals? how do you know?

Answer 22

a) to see if filling the stomach induces satiety
b) despite there being no absorption or nerve innervation occurring w/ the second stomach they still found that that the rats would still stop eating after having their ‘fill’
c) while there was no nerve innervation or nutritional absorption the BV were still connected thus this must be how the stomach indicates satiety
d) short due to it having an immediate effect on satiety

Question 23

Which of the following induces hunger?
a) insulin
b) glucagon
c) colecystokinin (CCK)
d) ghrelin
e) 5-HT

Answer 23

d

Question 24

Ghrelin is known as the hunger peptide what are 3 facts wrt it?

Answer 24

1. encourages eating
2. influences GHs (growth hormones)
3. mainly released by the stomach

Question 25

Right before a meal Ghrelin _____ in the blood then right after a meal ghrelin ______.
a) DEC, INC
b) DEC, DEC
c) INC, DEC
d) INC, INC

Answer 25

c

Question 26

wrt colecytokinin
a) where is it synthesized?
b) how does it influence the pancreas?
c) how does it influence the stomach?
d) what behaviour is exhibited by rats?

Answer 26

a) in the duodenum
b) secretion of insulin and glucagon
c) inhibits the stomach from being emptied
d) reduced eating

Question 27

a) There was a study that injected CCK into a rat and found that it stopped eating. How may this not indicate that CCK causes one to feel full?
b) What is this known as?

Answer 27

a) some drugs when injected at certain doses make the rats feel sick and if they feel sick of course they will stop eating thus that may be the reason they stopped eating rather than it feeling full
b) conditioned taste aversion where you develop a dislike for certain tastes do to them making you feel sick

Question 28

a) What receptors does CCK bind to? - 2
b) where are these receptors abundant? - 1
c) What does this mean? - 1

Answer 28

a) CCK A and CCK B
b) hypothalamus
c) this brain regions is related to regulation of satiety

Question 29

How does 5-HT influence satiety? - 2

Answer 29

reduces hunger = makes you less attracted to food

Question 30

Which of the following satiety signals are long-term?
a) 5-HT
b) leptin
c) CCK
d) Ghrelin

Answer 30

b

Question 31

wrt leptin
a) where is it released from? - 1
b) long or short term satiety signals? How do you know? - 1
c) what gene is it associated w/? - 2
d) how does it influence satiety? - 2

Answer 31

a) adipose tissue
b) long b/c it results in weight regulation which happens over a long period of time
c) the Ob/Ob gene
d) it reduces hunger when INC adipose tissue (negative feedback sys)

Question 32

Distinguish the following leptin mutation disorders. Indicate which one can be treated and how.
a) Ob/Ob homozygous humans
b) db/db homozygous humans

Answer 32

a) leptin deficiency = unable to produce leptin (treated via leptin therapy)
b) leptin deficiency receptor deficiency = unable to produce leptin receptors

Question 33

Describe what would occur if you were to lesion the following sub regions of the hypothalamus. why were both theories dismissed?
a) lateral hypothalamus (LH)
b) ventromedial hypothalamus (VMH)

Answer 33

a) there was a lack of responsiveness in general
- aphagia = stop eating
- adipsia = stop drinking
b) they overate due to gaining weight thus they needed to eat enough to compensate for this new weight not the other way around
- hyperphagia = excessive eating

Question 34

What is wrong w/ pancake mice? - 4

Answer 34

they are homozygous Ob/Ob meaning they are unable to produce leptin resulting in them always feeling hungry due to there being no negative feedback sys involved in regulating adipose tissue

Question 35

What is the fxn of the hypothalamus?

Answer 35

regulation of feeding behavior

Question 36

Based on this picture label the following regions using the colours
a) ventricles
b) lateral hypothalamus
c) ventromedial hypothalamus
d) pituitary

Answer 36

a) blue
b) orange
c) green
d) light purple at the bottom