Obesity_Exam 3 Flashcards
How is obesity defined?
A metabolic disorder that develops when calorie intake exceeds caloric expenditure in genetically susceptible individuals.
How are appetite and satiety controlled?
Controlled from: Controlled by arcuate nucleus in hypothalamus – responsible for balancing
metabolism
Regulated by OREXINS NEURONS which increase appetite and decrease metabolism and ANOREXINS NEURONS which decrease appetite and increase metabolism.
what is white adipose tissue
Comprises the majority of adipose tissue
• Visceral (central) and subcutaneous (peripheral) stores
• Contributes to the regulation of energy homeostasis:
• Adipocytes are fat storing cells – store energy as TG, synthesize TG from glucose, mobilize energy from free fatty acids and glycerol
• Secrete adipokines hormone like cytokines secreted to regulate metabolic function and immune response
• Food intake, energy expenditure, lipid storage, insulin sensitivity
• Inflammatory response, coagulation, fibrinolysis, angiogenesis, BP regulation
What is white adipose’s role in obesity
- when energy balance is positive, excess fat is stored in mature white adipocytes, which undergo hypertrophy and adipogenesis (hyperplasia, formation of new fat cells from preadipocytes).
- viseral WAT is more likely to store fay by adipose tissue hypertrophy; produce more adiponectin, less leptin, and more inflammatory cytokines; and result in central (visceral) obesity
What is brown adipose tissue?
- Composed of mitochondria and iron (brown color)
- Generates heat (like when you are cold)
- Neonates > adults
What is brown adipose tissue’s role in obesity?
Does not play a role in appetite or satiety, therefore no negative metabolic effects
What is beige adipose tissue?
Appears in extreme cold, with exercise
What is beige adipose tissues’s role in obesity?
Protective against obesity, increases energy expenditure and weight loss In all bones, particularly long bones
What is bone marrow adipose tissue?
• Releases adipokines with osteoblast activity
• excess osteoporosis and cause inflammation associated with RA
-found in all bones (mostly long)
-excessive MAT is r/t osteoperosis
Ghrelin Hormone
OREXIN
Role:
Produced in the stomach in response to hunger
• Ghrelin receptors in hypothalamus»_space; release growth hormone:
• Release gastric acid
• Increase gastric motility
• Pancreatic secretion of insulin
• Lean individuals – elevate with hunger and fall after eating
• In obesity, levels remain elevated after eating à
increased body weight and fat mass
Enocannabinoids Hormone
OREXIN
Role:
• Produced in brain and peripheral nerves
• Increases appetite, nutrient absorption and
lipogenesis
• Increase peripheral and central adipose tissue
accumulation
cdc definition of obesity
• CDC definition:
- Adults: obesity BMI >30kg/m2; morbid obesity BMI > 40kg/m2
- Children: BMI ≥95th percentile for age and gender
Leptin Hormone
Anorexin:
Role:
• Produced by adipocytes, acts on hypothalamus
• Decreases appetite and energy expenditure
• As adipocytes increase, leptin secretions increases
• High levels of leptin loose effectiveness (leptin
resistance) à disrupts hypothalamus signals of
satiety à overeat à increase weight
Glucagon like peptide 1 Hormone
Anorexin:
Role:
• Stimulates pancreatic glucose-dependent insulin secretion
• Decreases gastric emptying
• Decreased appetite and increased satiety
Adiponectin Hormone
Anorexin
Role: Levels will decrease in obesity >> • Increased insulin resistance • Increased CAD risk • Increase inflammatory markers
