Hunger guided notes Flashcards
Energy is supplied to the body in the form of
Lipids, Amino acids and glucose
fat = 85 percent
proteint (muscle) = 14.5
glucose is the
brains energy source. this is stored as glycogen (in the liver)
WHat is the diffierence between the pancreatic hormones glucagon and Insulin
Glucagon (stimulates conversion from glycogen to glucose) - ready energy
- Insulin (stimulates conversion from glucose to glycogen) - stored energy
WHat are the 3 phases of energy matabolism
1: cephalic phase: prepatory phase, which is intiated by the sight, smell or expectation of food = insulin high, glucagon low
2: absorptive phase : nutrients from a meal meeting the bodys immediate energy requirement with the excess beiing stores = insulin high, glucagon low
3: fasting face: energy being withdrawn from stores to meet the bodys immediate needs =
insulin low, glucagon high
WHat is the set point assumption
The set point theories of hunger and eating are a group of theories developed in the 1940s and 1950s that operate under the assumption that hunger is the result of an energy deficit and that eating is a means by which energy resources are returned to their optimal level, or energy set point.
body wants to maintain homeostasis
Differentiate between the glucostatic and lipostatic set point theories of hunger and eating
While the glucostatic theory holds that hunger and satiety are due primarily to short-term shifts in blood glucose levels (or utilization rates), (we become hungry when our blood glucose levels drop significantly below their set point)
lipostatic hypothesis states that the humoral signal which influences central structures must be related to long-term changes in the body fat (adipose tissue stores). (states that every person has a set point for body fat and deviations from this set point produce compensatory adjustments in the level of eating to return body back to set point)
WHat are the inconsistences of set point theories
- eating disorders, obesity epidemic,
- inconsistent with evolutionary pressures (banking food when available)
- people with excess fat dont adjust meal size
WHat is the positive incentive perspectve
- this was developed to overcome shortcomings of set point theories
Emphasize anticipanted pleasure of eating and craving
The central assertion to the positive-incentive perspective is the idea that humans and other animals are not normally motivated to eat by energy deficits, but are instead motivated to eat by the anticipated pleasure of eating
animals eat in response to;
- preferred flavours
- past experiences
- time since last meal
- others eating
The key findings from MacCormack and Lindquist’s study of ‘hanger’
They proposed that hunger alone is insufficient for feeling hangry. Rather, we hypothesize that
people experience hunger as emotional when they conceptualize their affective state as negative, high
arousal emotions specifically in a negative context.
that hunger causes individuals to experience negative emotions and to
negatively judge a researcher, but only when participants are not aware that they are conceptualizing their
affective state as emotions.
What are some factors that influence what we eat
animals:
- prefer sweet and salty
- aversion to bitter
- conditoined to taste preferences
craving for deficiencies: e.g. sodium
WHen food is readily available:
- humans focus on a few large meals per day
- eating as a stressor - eating stresses the body
Weingarten research on rats:
hunger is caused by expectations not energy deficit
WHat are some additonal factors that infleunce how we eat
Satiety is the perceived feeling of fullness
Describe the evolution of thinking in relation to the hypothalamus and the role of specific nuclei in hunger and satiety
OLD = used ot think the VHM and LH controlled hunger and satiety
NEW= paraventicular nucleous + arcuate nuclues
appetizer effect
eating a small amount before meal increases size of meal
The more variety of food
The more we eating today. Problem in today society with abundance of food
sensory specific satiety
why we often missunderstand that full feeling.
when you feel full not neccsairly means you’r full but how interested you are in contuning to eat that food
@ive just had enough of that food, i want something else@
thats why we can eat desert after meal
when we have a lot of variety more likely to continue eating
structures that play a role in satiety
early work the ventromedial hypothalamus was known as a satiety centre (increased eating)
The lateral hypothalamus was known as the hunfer centre (animals stopped eating and drinking when lesion here)
Hypothalamic nuclei now focus for research
problem with VMH as satiety centre
new reserch suggests they overeat becuase they become obese
many effects of VHM lesions are not attributed to VHM damage
humans expend most of their energy on
maintaining basal metabolis
which area of the hypothalamus seesm to be crtical for the ending of meals?
paraventicular nucleus
the hypothalamus is a collction of nuclei. different parts have differnet functions
The PVN is the feeding centre - appreciate satiety peptides
when in fasting stage - leptin released nd send message to brain stopping arculate nucleous from send neuro peptide to PVN.
Explain the role of leptin and insulin as feedback signals for the regulation of body fat
Leptin signals the brain when there’s enough fat, reducing appetite and increasing energy expenditure. Insulin helps store excess glucose as fat and inhibits fat breakdown. Both hormones regulate body fat and energy balance.
Obese humans found to have high, rather than low levels of leptin
Outline the reasons for the prevalence of obesity
Fast food” society, “obesogenic environment”
* Evolution (not adaptive when food is readily
available & high calorie)
* Prefer high-calorie foods
* Eat maximum capacity
* Store energy as fat
* Use calories efficiently
* Social factors
* Eat at specific times
* Eat maximum amounts
what are the main features of anorexia nervosa
Self-starvation plus psychological disturbances
* 1-2% of population
what are the main features of Bulimia
Binge-eat & purge in absence of extreme weight loss
* Erratic cycles, suggesting hypothalamic involvement
* Dangers of repeated vomiting (e.g., poisoning & result in heart failure;
can affect heart rhythms & damage kidneys, stomach, oesophagus, teeth)