hunger, eating and health

Question 1

mouth and salivary glands

Answer 1

mastication/chewing and saliva (alkaline)

Question 2

oesophagus

Answer 2

• transporting food to stomach

- set up for alkaline conditions as stomach is acidic

Question 3

stomach

Answer 3

• churning food and breaking it down

- acid digestive enzymes

Question 4

liver/gall bladder

Answer 4

-additional enzymes added to small intestine

Question 5

pancreas

Answer 5

-produces insulin and glucagon to store and release energy

Question 6

small intestine

Answer 6

-absorbs nutrients

Question 7

large intestine

Answer 7

-removes water and packs waste

Question 8

rectum/anus and bladder

Answer 8

store and expels waste

Question 9

pancreatic hormones

Answer 9

• insulin: shifts carbs from blood–>storage (glycogen, proteins)
• glucagon: shifts fuel from storage to where it is needed (glycogen–>proteins, carbs, frees fat stores to use as fuel when glucose low)

Question 10

why is our intake so complex?

Answer 10

• we are omnivorous
• diet includes range of key elements that our bodies have evolved to process
• lots of variation between species e.g. number of stomachs
• some variation within species e.g. dairy/gluten tolerance

Question 11

what is the outcome of digestion?

Answer 11

• lipids/fats–>fats - largest + most efficient energy store
• amino acids–>proteins - mostly in form of muscle tissue
• glucose–>glycogen - stored in muscles and liver, fast release
• minerals + vitamins–>body structure e.g. bones, cell structure

Question 12

how do we ensure these outcomes of digestion occur?

Answer 12

• homeostasis/set point theory - when we’re running low on food we experience: hunger and craving
• brain sensitive to shortage of glucose (hypothalamic regulatory nuclei)
• liver sensitive to shortages of glucose + lipids
• stomach sends signals to brain via release of ghrelin

Question 13

why does eating go wrong sometimes?

Answer 13

• internal factors e.g. learning, emotions

- environmental factors e.g. toxic environments

Question 14

homeostasis

Answer 14

when running low on fuel
-hunger (motivational state) due to low levels of fatty acids+glucose
-craving (automatic behavioural state)
body corrects by releasing glucose + taking in more food

Question 15

why do we feel full/satiety?

Answer 15

short term satiety signals: adequate glucose + lipid levels detected in brain + liver

• stomach distension- swollen
• buccal activity - lots of chewing
• high levels of sensory stimulation - big on taste + smell
• appetite suppressant chemicals e.g. caffeine, amphetamines
• diet products try to offset adequate levels with these factors

Question 16

what does research say about the brain and satiety?

Answer 16

• some research says hypothalamus is centre for satiety
• recent evidence suggests there isn’t such
• looks like it is hormonally controlled: ghrelin, neuropeptide Y, serotonin

Question 17

what hormone do fat tissues secrete? function?

Answer 17

leptin

• increases body metabolic rate
• decreases food intake by desensitising brain to hunger signals + inhibiting the effect of other hormones that drive eating

Question 18

what is the satiety cascade?

Answer 18

sensory(beliefs)–>cognitive–>post-ingestive(stomach+intestines)–>post-absoptive(liver+metabolites)

Question 19

health implications from poor eating:

Answer 19

nutritional deficits: scurvy, rickets, Korsakoff’s syndrome
starvation effects either immediate, long-term or both:
-concentration
-socially withdrawn
-physical + mental development stunted
-emotional instability
-all physical systems
starvation effects can pass to generations
-obesity in child of starved mothers

Question 20

obesity

Answer 20

• affects multiple systems e.g. social functioning
• strong link to premature mortality
• related to specific problems in children e.g. bullying

Question 21

what are the factors that oppose homeostasis?

Answer 21

• genetics
• learning
• social learning
• social pressures
• food industry
• ‘toxic environment’

Question 22

genetic/evolutionary factor

Answer 22

• genetic factors make us more likely to eat certain foods
• predisposed to high energy, high-taste foods
• less likely to enjoy bitter

Question 23

learning factor

Answer 23

-learned taste preferences and aversions influenced by culture, upbringing, satiety to specific foods(e.g. eat a varied diet)

Question 24

social learning factor

Answer 24

• we eat in a number of ways that match people around us
• imitation of how/amount/speed
• cultural influence

Question 25

social pressures/environmental factors

Answer 25

• lighting- eat more in dim light
• temperature - eat more when cold
• smells
• location of food

Question 26

agriculture and food industry

Answer 26

• food industry goes through stages in level of positive/toxic influence
• ensuring we’re not starved due to increasing pop- Malthusian hypothesis
• toxic rn: cheap, unhealthy food sold in large quantities, healthy foods out of season
• high fructose corn syrup related to obesity

Question 27

toxic environment factor

Answer 27

• in cultures where food scarce–>obesity valued as status symbol + vice versa
• evolved to grab food bc high-energy was only seasonally available h/e now it is abundant and easier to get
• unhealthy foods cheap, exercise–>screens