apetite regulation Flashcards
define appetite
the desire to eat food
define hunger
need of eating
define satiety
the feeling of fullness
disappearance of appetite after a meal
whats an underweight BMI
less than 18.5
how to calculate BMI
weight (kg) / height (m2)
whats a normal BMI
18.5 - 24.9
whats an overweight BMI
25.0 - 29.9
whats an obese BMI
30.0 - 39.9
whats a morbidly obese BMI
more than 40
risks of obesity
- Type II diabetes
- Hypertension
- Coronary artery disease
- Stroke
- Osteoarthritis
- Obstructive sleep apnoea
- Carcinoma
- Breast
-Endometrium
-Prostate
-Colon
- Breast
what factors determine obesity
- what regulates weight and appetite?
- why do most people keep a constant weight?
- why are people getting fatter?
- what can we do about it?
what does weight regulation depend on
environment + genes-> maintenance (homeostasis) system -> normal fat mass
negative feedback
why do we eat
- Internal physiological drive to eat
- Feeling that prompts thought of food and motivates food consumption
- External physiological drive to eat
- Sometimes even in the absence of hunger (e.g. buffet)
where is the hunger centre in the hypothalamus
lateral hypothaalus
where is the satiety centre in the hypothalamus
ventromedial hypothalamic nucleus
what factors control apetite
- psychological factors
- cultural factors
- neural afferents
- gut peptdes
- metabolites
- hormones
what does leptin do
switches off appetite and is immunostimulatory
what happens to blood levels after a meal
they increase
what happens to blood levels after fasting
they decrease
describe satiety of different nutrients
Highly refined sugar – quick and short satiety
Low glycaemic index foods – better
High protein – prolonged satiety
High fat – stimulate and entice people to eat more
describe peptide YY
36 amino acids
Structurally similar to NPY
Binds NPY receptors
Secreted by neuroendocrine cells in ileum, pancreas and colon in response to food
Inhibits gastric motility
Reduces appetite
describe cholecystokinin CCK
1973 – administration – reduced feeding in rodents
Receptors in pyloric sphincter
- Delays gastric emptying
- Gall bladder contraction
- Insulin release
And via vagus – satiety
describe ghrelin
28 amino acids
acyl side chain
expressed in stomach
what does ghrelin do
stimulates release of growth hormone
stimulates appetite
what allows understanding of underlying pathways
Animal and human models
is monogenic obesity common
no its rare
