Neural And Hormonal Mechanisms Invovled In The Control Of Eating Flashcards
Outline neural mechanisms in the control of eating
Ao1:
1) homeostasis: mechanism that maintains steady environment. Glucose controls hunger and decline activates the lateral hypothalamus, causing hunger. Higher glucose levels: ventromedial hypothalamus (on off switch)
lateral: research shown damage to LH in rats causes aphagia(lack of eating), when neuropeptide (Npy) injected they immediately fed
VM hypothalamus : damage caused rats to overeat therefore vmh signals turn eating off
Evaluate the neural explanations for the control of eating
Evaluate:
1) LH: ve: for hunger to be adaptive, mechanisms must be able to anticipate and prevent energy deficit. In reality, we need to maintain energy levels far higher than needed for future.
2) LH: -ve: concept that it’s just an on switch is limited as research revealed ppl with damage had sex deficits.
3) VMH: +VE: lesions cause hyperphagia and obesity in multiple species include humans.
Outline and evaluate hormonal mechanisms (list)
1) intro
2) ghrelin
3) EVAL: support: buffet
4) leptin:
5) EVAL: leptin resistance
Outline + evaluate ghrelin
1) intro: 2 main, ghrelin increases apetite when hungry. Lepton decreases apetite when you have enough energy
2) ghrelin: released in stomach, stimulates hypothalamus and increases apetite.
+ Eval: research support: A randomised double blind study on 9 random ppl. Tested how much food they ate from buffet depending on if leptin or ghrelin was injected. Ghrelin ate 28% more
Outline and evaluate leptin in the control of hunger
3) leptin: lab studies found when genetically modified mice (designed to be obese) were given leptin, they lost weight. (It supresses Npy which stimulates eating. Activates sympathetic nervous system burns energy quicker
4) EVAL: leptin resistance: some develop a resistance to leptin and cannot control eating. Found in obese people.
