Appetite Flashcards
What are the symptoms of metabolic syndrome?
- insulin resistance
- central obesity
- dyslipidaemia (high levels of VLDL and LDL, low levels of HDL)
- hypertension
Where is the appetite control centre located?
arcuate nucleus in the hypothalamus
What is the difference between the function of primary and secondary neurones of the arcuate nucleus?
Primary: sense metabolite levels and respond to hormones
Secondary: synthesise input from primary neurones and co-ordinate a response via the vagus nerve
Describe the difference between excitatory and inhibitory primary neurones
Excitatory- Stimulate appetite via release of neuropeptide U and agouti-related peptide
Inhibitory- Suppresses appetite by releasing pro-opiomelanocortin (POMC). POMC released in response to full stomach, causing endorphin release (feelings of euphoria and tiredness)
What are some of the products of enzymatic cleavage of POMC?
- polypetide prohormone
- enzymatic cleavage can result in:
- Beta endorphin
- ACTH
- alpha-melanocyte stimulating hormone (alpha-MSH). Acts on melanocortin 4 receptors to suppress appetite
Describe the effect of PYY on appetite
- peptide hormone
- released from wall of small intestine
- decreases appetite
Describe the effect on insulin on appetite
-works via same mechanism as leptin
Describe the effect of leptin on appetite
- peptide hormone
- secreted by adipocytes into bloodstream
- stimulates inhibitory neurones and inhibits stimulatory neurones
- ‘satiety hormone’
- induces uncoupling protein expression in mitochondria causing heat loss
Describe the effect of ghrelin on appetite
- peptide hormone
- released from wall of empty stomach
- activates stimulatory neurones of arcuate nucleus
- full stomach inhibits ghrelin release
Describe the effect of amylin on appetite
- secreted by beta cells of pancreas
- reduces appetite
- reduces glucagon secretion and slows gastric emptying
What is the Barker hypothesis?
The experience of the foetus in utero during development somehow determines the future health of the individual
What is an epigenetic trait?
a stably inherited phenotype resulting from changes in a chromosome without changes in DNA sequence
