Met 2: Regulate Body Weight Flashcards
How do we know that environment is the main reason for recent obesity increase?
Because obesity has increased dramatically in too short of a time frame for it to be genetic changes
Three components of energy expenditure
- Basal metabolic rate
- Based on lean body mass
- Thermic effect of feeding
- Physical activity
How do we adapt to changes in our caloric intake? (4)
- Burn more/less calories (activity, RMR)
- Change nutrient utilization
- Change nutrient absorption from GI tract
- Change in appetite
Effects (2) of the anabolic brain pathway
Describe its signaling
- Anabolic pathway increases food consumption and decrease energy expenditure
- NPY released by arcuate nucleus binds to lateral hypothalamus
Effects (2) of catabolic pathway
Describe its signaling
- Catabolic pathway decreases food intake and increases energy expenditure
- POMC neurons in arcuate nucleus makes MSH, which binds to MCReceptor in ventral thalamus
Where is the hunger center?
Lateral nucleus of hypothalamus generates hunger
Lat makes you fat
Where is the satiety center?
Ventromedial nucleus of hypothalamus causes feeling of satiety
Ven keeps you thin
What is leptin?
Long-term signal from adipose tissue that inhibits anabolic pathways in the brain
How does leptin affect the hypothalamus? (2)
- Leptin stimulates catabolic pathways in ventromedial hypothalamus (POMC neurons in arcuate nucleus)
- Leptin inhibits anabolic pathways in lateral nucleus of hypothalamus (NPY neurons in arcuate nucleus)
What is the effect of insulin in the hypothalamus?
SAME as leptin
Leptin receptor deficiency causes _______
Does this mean we can give leptin to obese people as treatment?
Leptin receptor deficiency causes obesity
BUT, obese individuals without this genetic deficiency will have leptin-resistance and will not lose weight with leptin administration
What is the effect of Ghrelin?
Where is it made?
Is it short-term or long-term
- Short-term signal
- Stimulates hunger
- Stimulates NPY neurons in arcuate nucleus to release NPY onto lateral hypothalamus
- Released by gut
What is PYY and GLP-1?
Where is it made?
- Satiety signal
- Stimulates POMC neurons in ARC to release MSH onto ventromedial hypothalamus
- released by gut
What’s the idea of a set point?
Our bodies are designed to exist at a certain weight, and we will naturally come back to this set point after weight changes
Obese individuals demonstrate a _______ response to leptin
Obese individuals demonstrate a decreased response to leptin
(aka leptin resistance)
