Appetite Control Flashcards
How does the satiety centre sense and respond to input?
Primary neurones sense glucose and fatty acids in blood, and either activate excitatory or inhibitory neurones, or the secondary neurones
Secondary neurones synthesise input and coordinate a response (usually by vagus nerve)
Where and what is the satiety centre?
Hypothalamus: arcuate nucleus
How do the excitatory and inhibitory neurones affect appetite?
EXCITATORY = stimulates NPY and AgRP which stimulate appetite
Activated by ghrelin
Inhibited by PYY
INHIBITORY = stimulates POMC which activates beta-endorphin (euphoria) and alpha-MSH (supresses appetite)
Activated by PYY, leptin, and insulin
Outline some hormones which stimulate or inhibit the excitatory and inhibitory neurones.
Ghrelin (peptide hormone - released from wall of stomach) = stimulates excitatory neurones
PYY (peptide hormone - released from chyme in small intestine) = stimulates inhibitory neurones
Leptin (polypeptide hormone - released from adipocytes) = stimulates inhibitory neurones
(note: deficiency causes obesity due to hyperphagia)
Amylin (peptide hormome - beta-cells in pancreas) = suppresses appetite
What is another factor in appetite control not related to stomach content?
Hedonic input = psychological dependence on food
Outline the symptoms in metabolic syndrome. What can these lead to?
Central adiposity (low waist:hip ratio?)
Obese (BMI>30)
Hypertension
High TAGs & cholesterol
Hyperglycaemia
Decreased glucose uptake (insulin resistance)
Risk factors for: CVD, strokes, Type II diabetes
What is the Barker hypothesis? What are some examples demonstrating this?
Association between adult disease and low birth weight
Could be due to foetal programming: foetus adapts to conditions in utero e.g. supply of nutrients; adaptation to supply programmed in
e.g. 2D:HD predictor of disease incidence
