The Neurophysiology of Appetite Control Flashcards
What are the brain pathways involved in appetite?
Hypothalamus (connections to hind & limbic)
Orbitofrontal (sensory meets hedonic)
What is the definition of hunger?
The physiological need to eat food
What is the definition of appetite?
The desire to eat food
What is the definition of satiety?
Absence of hunger (feeling full)
What are three factors that are involved in feeding and appetite?
Processing sensory information (motivation & learning)
Evaluating desirability (reward representations)
Choosing appropriate behaviour (hedonic experience)
What sensors are involved in feeding and appetite?
5 sensors
GI sensory receptors: distention
Cardiovascular receptors: BP & CO2 in blood
What effectors are involved in feeding and appetite?
Hypothalamus & its interconnections
Orbitofrontal Cortex (sensory meets hedonic)
When the lateral hypothalamus is stimulated, what does it make you feel?
Hungry (hunger centre)
What does a lesioned(destroyed ) lateral hypothalamus mean?
You will never be hungry again
What does a lesioned (destroyed) ventromedial hypothalamus mean?
You will never be full again
When the ventromedial hypothalamus is stimulated, what does it make you feel?
Full (satiety centre)
What are neural signals from GI tract for short term regulation of human food intake?
Stretch receptors inhibit appetite
Vagus nerve/ GI tract to hypothalamus
What are nutrition signals of short term regulation of human food intake?
Rising blood glucose levels
Elevate blood levels of amino & fatty acids
Which hormones inhibit hunger?
Insulin & Cholecystokinin (CKK) released from GI tract
Leptin (adipose tissue)
Which hormones stimulate hunger?
Glucagon & Adrenaline (fasting)
Ghrelin (stomach)
What effects does resistin have?
Increases liver production of LDL
Decreases LDL receptors in liver
Accelerates accumulation of LDL in arteries
What are the effects of resisting linked to?
Increases obesity & type 2 DM
Increases inflammation & insulin resistance
Increases pro-inflammatory cytokines
Decreases response to statins
What neurotransmitters are involved in eating?
5HT, GABA, DA
What neuropeptides are involved in eating?
Neuropeptide Y (NPY)
Orexins (OX)
Melanin-concentrating hormone (MCH)
What does it mean if something is orexigenic?
It stimulates feeding
What does it mean if something is anorexigenic?
It inhibits feeding
What does the abdominal viscera communicate with the brain regarding?
Processing of ingested food
Metabolic effects of the absorbed nutrients
Gut endocrine secretions
What are the means of communication for hormonal responses?
G.I , pancreatic & brain peptides
What are the means of communications for neutral responses?
Vagal & spinal visceral afferents from the gut
