Ingestive behaviours Flashcards
What are the biopsychosocial factors that influence eating behaviours?
Biological: genetics, history of dieting
Psychological: perfectionism, difficulty regulating emotions, body dissatisfaction
Social: pressure for body shape, bullying, lack of support
What are the mechanisms of thirst?
Stimulation of subfornical organ (SFO) and organum vasculosum of the lamina terminalis (OVLT) triggers thirst
Controlled by GI afferents and baroreceptor inputs
Median preoptic nucleus (MnPO) signals the insula (interoception) and cingulate cortex (motivation/emotional processing)
What areas of the CNS are involved in hunger perception?
Hypothalamus:
Lateral hypothalamus - hunger centre (damage->anorexia)
Ventromedial hypothalamus - satiety centre (overeat->obese)
What are the feedback mechanisms that control appetite and food intake?
-Stretch receptors in stomach: activate sensory afferent pathways in the vagus nerve - inhibit food intake
- Peptide YY (PYY), cholescystokinin (CCK) and insulin are GI hormones released after ingestion - supresses food intake
- Leptin = hormone produced by fat cells proportionally. Inhibits food intake
- Ghrelin = released by stomach esp during fasting = stimulates appetite
What are examples of anorexigenic hormones?
Anorexigenic - decreases appetite
a-melanocyte-stimulating hormone
Leptin
Serotonin
Norepinephrine
Corticotrophin-releasing hormone
Insulin
Cholecystokinin
PYY
What are examples of orexigenic hormones?
Orexigenic - increase appetite
Neuropeptide Y
Agouti-peptide protein
Endorphins
Orexins A and B
Ghrelin
Cortisol
Galanin
What are the 5 modalities of taste?
Sour - acids (H+ ions)
Salty - ionised salts
Sweet
Bitter - long chain organic substances containing nitrogen and alkaloids
Umami - containing L-glutamate
How may taste be modulated?
Angiotensin II: decreases sensitivity to salty, increases sensitivity to sweet
Glucagon: increases sensitivity to sweet
TNF-a: decreases sensitivity to some bitter
What is pica?
Craving for eating non-food substances
Related to micronutrient deficiencies
Cause and effect of sodium appetite
Elicited by sodium depletion
Sodium appetite increased drive to eat salty foods
RAAS reduces sodium appetite in animals
Name the models explaining eating behaviours
Developmental model
Cognitive model
Weight concern model
What is the development model?
Infleunced by
Associative learning - reinforcement, food as reward, control
Social learning - modelling, social context
Suggest obtaining and maintenance of eating habits is learnt
What is the Barker hypothesis?
Intrauterine growth restriction/low birth weight may predispose children to obesity and metabolic syndrome
What is the cognitive model?
Behavioural attitudes, subjective norms, perceived control > intention > eating behaviour
- Beliefs, values and attitudes e.g veganism
- Food myths
What is hedonic eating? (3)
- Eating activates our mesocorticolimbic dopaminergic pathway = associated with pleasure
- Different from eating for the needs of our bodies (homeostatic eating)
- Comfort eating can be a way of medicating ourselves against negative emotions
