15- Hunger and Satiety Flashcards
Hypovolemic thirst stimulated by
Reduced extracellular volume
Osmotic thirst (cellular dehydration) stimulated by
High extracellular solute concentration
BMI =
Mass/(height)2
The body uses energy in 3 primary ways
- Basal Metabolism: 55%
- Digestion of food: 33%
- Active Behavioural processes: 12-13%
Primary ‘fuel’ for the body
Glucose
What is an error detector
Compares actual versus set-point state
What is an error correction mechanism
Negative feedback mechanism
Two basic types of set-points are
- Glucostatic Set-Point Theory: Eating is controlled by deviations from a hypothetical blood glucose
- Lipostatic Theory: Eating is controlled by a hypothetical body-fat set-point
Damage to lateral hypothalamus (LH) causes
A large decrease in feeding (aphagia) & reduced body size
Damage to the ventromedial hypothalamus (VMH) causes
Increasing feeding (hyperphagia)
Recent work shows that the LH contains
Glucose receptors (along with the liver)
LH brain self-stimulation is what in rats
Rewarding
Brain sites where stimulation causes eating are the same sites where
Self-stimulation is rewarding
What are ghrelin and orexins
Peptide hormones secreted in the gut and from adipose tissue + hypothalamus, respectively
What does Orexin and Ghrelin administration do
Increase hunger
What is Cholecystokinin (CCK)
A hormone released in the intestines in response to fat
What is Peptide YY (PYY)
A hormone released in the intestines in response to food
CCK injections inhibit what
Subsequent feeding
Injections of PYY inhibit what
Eating
What levels of PYY may be in obese individuals
Abnormally low
Genetic leptin deficiency is associated with what
Obesity
Leptin binds to receptors in what
The ventromedial nucleus of the hypothalamus
