Flashcards in Physiology of feeding and satiety Deck (50)
What is energy homeostasis?
Physiological process whereby energy intake is matched to energy expenditure over time
How is energy primarily stored?
Promotes body fuel stability
What leads to obesity
Accessible, tasty calorie dense food and sedentary lifestyle. This is due to a small constant mismatch between energy intake and energy expenditure
What are some consequences of metabolic stress?
type 2 diabetes
At what BMI is a someone classified as overweight and then obese and morbidly obese?
Overweight = 25-29.9
Obese is 30-39.9
Morbidly obese is more than 40
What has a dramatic increase in obesity caused?
A global epidemic
Describe obesity as a general disorder
Not a single disorder, but a heterogeneous group of conditions with multiple causes
What are the major influencing factors on obesity
Genetics (fatness through susceptible genes) and environment (compare food in USA to Africa)
What are some of the consequences of obesity?
respiratory disease (sleep apnoea)
Heart disease (lipids, diabetes, hypertension)
NAFLD (fatty liver)
Cancer (uterus, breast, prostate, colon)
Name 3 reasons of why we need fat?
Prevention of starvation
Energy buffer during prolonged illness
why is obesity described as a disease of the brain?
Difficult to lose weight once gained
Increased body fat alters the brain function
Long term obesity induces brain re-programming
Your brain biews the extra weight (fat) as normal and dieting as a threat to the body's survival
How does the CNS influence energy balance and body weight?
Behaviour - feeding and physical activity
ANS activity - regulates energy expenditure
Neuroendocrine system - secretion of hormones
Where is the site of integration
What is the area responsible for control of energy intake and body weight?
Lesioning ventromedial hypothalamus causes what?
Lesioning lateral hypothalamus causes what?
What 3 basic concepts underlie the control of energy intake and body weight?
Satiety signalling (sensation of fullness generated during a meal between termination of one meal and the initiation of the next)
Adiposity negative feedback signalling (state of being obese)
What happens to the satiation signals during a meal
They increase to limit the meal size
Where is Cholecystokinin (CCK) secreted?
From enteroendocrine cells in the duodenum and jejunum
How is the volume of CCK regulated?
It is released in proportion to lipids and proteins in a meal
Where is Peptide YY (PYY3-36) secreted?
From endocrine mucosal L cells of GI tract.
How are the levels of PYY3-36 monitored?
They increase rapidly pst prandially
What is the role of PYY
To inhibit gastric motility, slow emptying and reduce food intake
What is glucagon-like peptide 1 (GLP-1)
Product of pro-glucagon gene.
Where is GLP-1 released from?
L cells in response to food ingestion
What does GLP-1 do?
Inhibits gastric emptying and reduces food intake
Where is Oxyntomodulin (OXM) released from?
Oxyntic cells of the small intestine after a meal
How does OXM act?
Acts to suppress appetite - although the mechanism is unnclear
What is OXM
A product of pro-glucagon gene