Hunger and Motivation Flashcards
What was the initial hypothesis for what caused hunger? (washburn, cannon). What was the fatal flaw here?
that stomach contractions (grumbling) caused it. Hunger abounds even when stomachs removed
Which part of the brain controls hunger? How is it divided? What was the misconception here?
Hypothalamus. Divided into: Lateral hypothalamus (LH) (Hunger) Ventromedial nucleus (satiety) Misconception: on/off switches. More just increases levels of each
What did the removal of the LH and Ventromedial Nucleus do to rats?
LH: starved to death
N: ate until death
What is the more correct theory about hunger control in the brain?
Arcuate nucleus and paraventricular nucleus are more important at controlling it. They contain neurons that detect hunger/fullness levels
Generally, what’s wrong with the on/off switch theory?
Really should focus on interconnection of circuits instead
Explain the Glucostatic theory. How does it leave room for alternative explanations?
When blood sugar/glucose drops, hormones are released that trigger hunger (like an empty tank light). Reason: glucose levels fluctuate very slowly
How does the stomach itself regulate hunger?
Vagus Nerve: Cells in stomach send signals when they are expanded / stomach is full of food
Also cells that carry info on nutrients
Describe the first two hormones that regulate hunger. What does one cause dumbass?
- Ghrelin: excreted after long periods of no-food. Causes stomach contractions
- CCK: excreted from upper intestine that sends satiety signals to brain
Describe the NEXT two hormones that regulate hunger
- Leptin: carries info about fat stores, regulates feelings of long term hunger
- Insulin: from pancreas. extracts glucose from foods
How does insulin and diabetes work?
Diabetics have trouble extracting sugar from foods which they need (because they don’t have insulin) so why they need snacks
How does Ghrelin work against diets?
endoindocrine cells that are highest before meals (triggering hunger). But also slows metabolism. This results in you always wanting to eat, and being less able to burn fat when you do
What are the three key environmental factors for regulating hunger?
- availability of food
- Learned preferences and habits
- stress
Explain the first two food-availability related cues and how one relates to buffets
- Palatability: better food, will eat more of it
2. Quantity available: bigger portion sizes, will eat more. Also called bin model/heuristic
What did that study about buffets revealed?
When bigger plates were offered, people ate 45% more and wasted 125% more
What are the next three food-availability related factors for regulating hunger?
- Variety: if there are fewer types of food, you will eat less because they will become less palatable more quickly
- Presence of others: generally eat more when with people, especially lots of people, but not on dates
- Stress: makes you crave fatty, sugary foods
Names some environmental cues that also cause hunger
Ads, smells, kitchen
Though food consumption varies across cultures, what is one innate taste we have?
Kids all love sweet things
How are taste preferences formed?
Classical conditioning: association of food with good things
Give an example of how habits and culture impact eating
Though we CAN eat lunch whenever we want now, we’re still eating at around 12-1 (learned habit)
What is the relationship between the brain and sweet/fatty foods? What has brain imaging revealed?
That Limbic system (pleasure centre) is very active when consuming these. Mass release of dopamine
What might one biological condition of food addiction be?
People may have different ways of processing dopamine levels/rewards
Explain set point theory
We have a set point of weight that our body fights to maintain. Easier to gain/preserve weight then lose it
What about settling point theory? What is this influenced by?
Set weight within a range that is influenced by genetics, culture, exercise, etc
How is BMI calculated? What is obesity level bmi?
Body Mass Index: W/H/\2 >30
