Physiology: Feeding & Satiety Flashcards
What are some conditions closely related to obesity?
- Metabolic syndrome
- Type 2 Diabetes
- CVD
- Stroke
- Dyslipidaemia
How is BMI measured?
Weight (Kg)/ Height (m)
How much does a persons BMI need to be to be obese?
Over 30
Over 40 - Morbidly obese
What are the two Greatest factors that contribute to obesity?
- Sedentary lifestyle
- High fat diet.
What are two non modifiable risk factors for Obesity?
Genetics
Environment
Why is obesity known as a disease of the brain?
Long term obesity induces brain re-programming
Brain sees putting on weight as normal
Any forms of dieting/cutting down seen as abnormal.
Which part of the brain deals with energy balance and body weight?
Hypothalamus.
How does the CNS influence energy intake and weight? (3)
- Behaviour- feeding/physical activity
- ANS stimulation- regulate energy expenditure
- Neuroendocrine system- secrets hormones
Which 3 factors underline the control system?
- Satiety
- Adiposity negative feedback signalling
- Food reward
What is satiation?
The sensation of fullness generated during a meal
What is Satiety?
Period of time in-between two meals
What is adiposity?
State of obesity
What happens to Satiation signals during a meal? Why?
Increases. Limit meal size.
Which 5 Hormones carry out satiation?
- Cholecystokinin
- Peptide YY
- Glucagon-like peptide 1
- Oxyntomodulin
- Obestatin
What is Cholecystokinin released in proportion to?
Lipids and protein content of the meal
When is Peptide YY released? What does it do?
Post meal.
- Inhibits gastric motility
- Slows emptying
- Reduces food intake.
What is the role of Glucagon like peptide 1? (2)
- Inhibits gastric emptying
2. Reduces food intake
What is the effect of Oxyntomodulin?
Suppresses apetite
What is the effect of obestatin?
Reduces food intake. may suppress ghrelin
What is the function of Ghrelin? (2)
Hunger signal
Stimulates food intake.
Reduces fat utilisation
What is the main role of the feedback loop?
Maintains constancy of body energy stores
What are the effects of Glutamate, gaba and opiods?
Increase food intake
Effect of monoamines?
Suppress food intake
Which two hormones report fat status to the brain? (adiposity signals)
- Leptin
2. Insulin
What is the effect of these hormones on the brain?
Instructs brain to alter energy balance
- Eat less
- burn more energy.
Obesity- malfunction of above process
What do levels of insulin in the body depend on?
Proportionate to body adiposity
What does intra-cerebro-ventricular insulin do?
Inhibits food intake
Decrease body weight
What is food reward?
Pleasure gained from eating food
What does food reward stimulate in the brain?
Stimulates dopamine pathways.
Common pathway in drug/substance abuse
What is the main treatment for people who have genetic leptin malfunction?
Leptin therapy. Injections. Does work.
Why cant leptin therapy be used in most obese (diet driven) patients?
Obese patients develop Leptin resistance
What is the main drug used for obesity now?
Orlistat
What is the pharmacological effect of Orlistat? (2)
- Inhibits pancreatic lipase, reducing triglyceride absorption
- Reduces efficiency of fat absorption into small intestine?
What are the two major side effects of Orlistat?
Cramping
Severe diarrhoea
What is the mechanism of action of Contrave
Combo of
- Dopamine re-uptake inhibitor
- Opioid antagonist
What is the mechanism of Liraglutaide?
GLP1 receptor agonist
Is bariatric surgery effective treatment?
Yes
- Produces substantial weight loss
- Can permanently reverse Type 2 diabetes
How does DNP work?
Causes rapid fat loss by dramatically increasing body temp and metabolic rate.
