Obesity Flashcards
1
Q
Lipostat hypothesis
A
- Accounts for long term stability in body weight
- Involves endocrine and neural components
- Set point determined b genetic factors and can be reset by environmental factors
2
Q
Features of a lipostat
A
- Signal: Leptin
- Sensor: Leptin receptors in hypothalamus
- Effectors: Hypothalamic factors that control feeding, factors that control energy expenditure
3
Q
Leptin is proportional to
A
-Fat accumulation
4
Q
ob mutation in mice
A
- Lead to truncated and inactive leptin
- ob/ob mice acted as if they were starved
- Don’t produce leptin
- Increase in body weight and body fat
5
Q
db mutation in mice
A
- Don’t produce the leptin receptor in the hypothalamus
- Increased body weight and body fat
6
Q
AgRP neurons
A
- In hypothalamus
- Produce orexigenic effectors
- Increase food intake, lessen energy expenditure
7
Q
POMC neurons
A
- In hypothalamuss
- Produce anorexigenic effectors
- Decrease food intake, promote energy expenditure
8
Q
Leptin
A
- Stimulates anorexigenic effects (POMC neurons)
- Inhibits orexigenic effects (AgRP neurons)
9
Q
Leptin resistance
A
- Seen in obese people who already have high leptin levels
- Anorexigenic factors not stimulated
- Also rare genetic defect
10
Q
Adaptive (facultative) thermogenesis
A
- Shivering
- Nonshivering: promoted by brown fat tissue
11
Q
Brown fat cells
A
- Heat production
- Rich in mitochondria
- Express UCP1: uncoupling protein
12
Q
UCP1
A
- Uncoupling protein in brown fat cells
- Dissipates energy during thermogenesis
- Adaptive thermogenesis
