chapter 21 obesity Flashcards
Adipose tissue function is
- protection
- insulation
- secretes adipokines
- energy reserve
- immune cell division
- mechanical support
What are the classifications of adipose tissue
- white Adipose Tissue
- Brown Adipose tissue
- Beige Adipose Tissue
- Bone Marrow Adipose Tissue
White adipose tissue
- derived from connective tissue
- single lipid droplet
- located in the visceral and subcutaneous stores, and muscles
- releases free fatty acids and glycerol for energy metabolism
Brown Adipose Tissue
- derived from muscle tissue
- many droplets of lipid
- generate heat through oxidation of fatty acids
- neonaltal heat generation
- protects against obesity
- non shivering thermogenesis
Bone marrow adipose tissue
- found in all bones
- increases with obesity and age
Beige adipose tissue
- found in WAT and BAT
- emerge with chronic exposure to cold or exercise
- diminished obesity
Adipose tissue can acts as ….
endocrine gland that secretes adipokines
Adipokines are
- cell signaling proteins
- causes excess white adipose tissue secretion
- function as hormones
- impact on food intake
- impact insulin secretion and storage
- triggers insulin resistance
- affects BP
- affects bone metabolism
- affects fertility
- affects energy expenditure
Obesity
- increase in adipose tissue
- body mass index is > 30
- growth chart shows that 95% of growth in chidren
- develops when caloric intake exceedes caloric expenditure
- major cause of death who are obese is due to –
- cardiovascular disease
- Type 2 diabetics
- cancer
Risk factor of obesity
- environmental factors
- metabolic factors that cause obesogenic, chemicals that can impact genetics
- depression and mood disorders
- polygenic defects.
Pathophysiology of obesity
- signal mediators that act on hypothalamus and brainstem that regulate hunger and satiety
- interaction of peripheral and central pathways and numerous adipokines and neurotransmitters
Phenotypes of obesity
- Peripheral: distribution of fat around the thighs and buttocks and has a pear shape
- Visceral obesity: associated with more complications
- distribution of fat is localized around the abdomen and upper body giving the body an apple shape - Normal weight obesity: normal body weight and BMI with percent of bodyfat is greater than 30 %
- Metabolically healthy obesity: obese but no complications and low risk for morbidity and mortality
adipokines and obesity
- Leptin: causes leptin resistance which causes a loss in appetite
- adiponectin: increase energy expenditure
- retinal-binding proteins: increase inflammation
- endocannabinoids: increase appetite
- angiotensinogen: increase BP
- ghrelin: increase food intake and fat storage
- glucagon: stimulates pancreases
- peptide: decrease obesity
- cholecystokinin: causes bladder to contract
Starvation is
- decreased energy intake leading to weight loss
- can be due to malnutrition
Types of starvation
- Short term
- Long term
Short term starvation
- extended fasting for several days of dietary abstinence or deprivation
Therapeutic: causes initial rapid weight loss
Pathologic: glycogenolysis
- gluconeogenesis
Long term starvation
- begins after several days of dietary abstinence
Therapeutic: weight loss in morbidly obese people
Pathologic: anorexia nervosa, disease
- death from proteolysis
- marasmus: proteins energy malnutrition
- Kwashiorkor: proteins and carbohydrate deprivation
- cachexia
- refeeding syndrome
Anorexia of aging is ….
- decrease of appetite or food intake in older adults
- aging associated with decreased oxygenic signals and anoxygenic signals
Risk factors of anorexia of aging is
- functional impairments
- loneliness and grief ( social isolation)
- medical and psychiatric conditions
- abuse or neglects
clinical manifestations of anorexia
- malnutrition
- fragility
- mitochondrial dysfunction
- reduced regenerative capacity
- increased oxidative stress
- imbalanced hormones
How is food intake and energy balance regulated?
- by central and peripheral physiological signals
- arcuate nucleus in the hypothalamus balances opposing effects of neurons
- GI tracts secretes hormones that control hunger and satiety
oxygenic neurons are…
promote appetite, stimulate eating, and decreases metabolism
anorexigenic neurons are …
suppress appetite, inhibit eating and increase metabolism
