8 - hunger, eating and health Flashcards
the human digestive system
- mouth and salivary glands
- oesophagus
- stomach
- liver/gall bladder
- pancreas
- small intestine
what does the pancreas do?
produces insulin and glucagon to store and release energy
what does the small intestine do?
absorbs most nutrients from the food that we eat
what does the large intestine do?
removes water and packs waste
what do liver and kidneys do?
filter out toxins for excretion
what does glucagon do?
shifts ‘fuel’ from storage to where it is needed in the body
converts glycogen and proteins to carbohydrates
frees fat stores to use as fuel when the glucose stores are low
what does insulin do?
shifts carbohydrate from blood to storage (glycogen, proteins)
what do the liver and gall bladder do?
what are the three core products of digestion?
- lipids/fats
- amino acids
- glucose
what are the storage mechanisms of lipids/fats?
fats
largest and most efficient energy store
what area the storage mechanisms of amino acids?
proteins
mostly in the form of muscle tissue
what are the storage mechanisms of glucose?
glycogen
stored in muscles and liver
fast release
how do we ensure that our food needs are met?
- homeostasis/set point theory
- hunger
- craving
what are the mechanisms that make sure we eat when necessary?
- brain is sensitive to shortage of glucose
- liver is sensitive to shortages of glucose and lipids
- stomach sends signals to the brain if its unstimulated
how does homeostasis/set point theory make sure we eat when necessary?
- hunger (motivational state): due to low levels of fatty acids/glucose
- craving (automatic behavioural state)
body corrects by:
- releasing glucose
- taking in more food
what are short-term satiety signals?
- adequate glucose and lipid acid levels
- stomach distension (stretched)
- buccal activity (chewing)
- high levels of sensory stimulation (taste & smell)
- appetite suppressant chemicals (caffeine, amphetamines)
what does fat tissue secrete?
hormone - leptin
- increases body metabolic rate
- decreases food intake by
- desensitising brain to hunger signals
- inhibits effect of other humans that drive eating (neuropeptide Y)
what are long-term satiety signals?
- increased levels of leptin
ghrelin
neuropeptide Y
what is the Minnesota starvation experiment?
join the army or take part in experiment
- studied the effects of starvation on 35 men
- cognitive, socially, emotional affects of starvation and weight gain
how has the health implication of poor eating been studied?
- Minnesota starvation experiment
- dutch hunger winter
what are the health implication of poor eating?
- nutritional deficits
- starvation effects can be immediate/long term (emotional instability, concentration, social, development, physical systems)
- starvation effects can cross generations e.g. obesity in the children of starved mothers
what are the implications of obesity?
- affects multiple systems including social functioning
- premature mortality
- specific problems in children (bullying, self-esteem)
what factors take us away from homeostasis?
- genetics
- learning
- social pressures
- food industry
- toxic environment
