Control of appetite, metabolic syndrome, developmental origins of health & disease Flashcards
Which stimulatory hormones are involved in the control of appetite?
NPY & AgRP - promote hunger
Which inhibitory hormones are involved in the control of appetite?
POMC –> a-MSH & B-endorphine (through neurotransmitters) promoting satiety
How do hormones control appetite?
primary neurone –> secondary neurone –> modulated feeding behaviour
When is Ghrelin released? what is it?
peptide hormone released from stomach wall when EMPTY
released from stomach wall to hypothalamus
stimulate excitatory NYP & AgRP primary neurones
increasing appetite
filled stomach inhibits ghrelin release
Outline the control of appetite
satiety centre of hypothalamus: appetite control centre
hypothalamus’ arcuate nucleus
What is another hormone that is released from the gut to the hypothalamus apart from ghrelin which suppresses appetite?
PYY
released by cells in ilium & colon (small intestines), inhibits primary excitatory neurones, suppressing appetite
What happens when there is too much PYY and too little PYY
too much: patient becomes anorexic
too little: patient becomes obese
What’s a hormone released from the body to the hypothalamus?
Leptin - peptide hormone released to blood by fat cells (adipocytes)
stimulates POMC & suppresses NPY & AgRP - suppressing appetite
Aside from leptin, which other hormones are released from the body to the hypothalamus to suppress appetite?
insulin & amylin - both released from beta cells of pancreas
What is metabolic syndrome?
a cluster of risk factors associated to CVD
e.g. abdomin obesity, high BP, insulin resistance, raised fasting glucose, dyslipidaemia (high TAG, low HDL)
Which are the most significant risk factors of metabolic syndrome?
insulin resistance (high glucose conc = high insulin, beta cells can't keep up with production - so wear out) high glucose = type 2 diabetes & central obesity (hypertension, high cholesterol, hyperglycaemia)
cause unknown
What are the treatments for metabolic syndrome?
primary: healthy lifestyle, calorie restriction, physical activity, healthy diet
secondary: drug intervention, STATINS reduce LDL - cholesterol
antihypertensive lower bp, antidiabetic - hyperglycaemia
Explain developmental origins of health & disease theory in relation to epigenetics
if a pregnant women had a low nutrient intake, the child could be programmed for similar life, so insulin & leptin resistance fo harsh environment
if offspring have a life of plenty (excess nutrient uptake) then metabolism will drive hem to obesity, diabetes, metabolic syndrome
How do their epigenetics change?
hormonal changes, metabolic changes, altered cellular differentiation
epigenetic regulation: histone modifications e.g. methylation of histones (non coding RNA) - long term effects on gene expression, increased risk of disease
what is the importance of the DoHaD theory?
better understanding of origins of some diseases
highlight importance of antenatal care - adequate & appropriate nutrition
what’s a socioeconomical issue of the DoHaD theory?
women greatest risk of poor nutrition, least likely to present for antenatal care
examples of neg feedback
- release of cortisol from adrenal gland, suppressing release of TRH from hypothalamus & ACTH from pituitary gland
- hypoglycaemia stimulating release of insulin - decreasing blood glucose conc.
example of positive feedback
blood clotting: signalling cascade to change blood from liquid –> solid
ovulation - LH surge
What are hormones?
number of tissues that synthesise chemical signals
signals can be protein molecules, steroids, AA derivatives
How do steroid & thyroid hormones travel in the blood? why?
they are lipophilic, so require specialist transport proteins e.g. albumin
Describe how hydrophobic hormones travel and function?
transported in blood by specialist protein, can cross target cell plasma membrane, interact with intracellular receptors & bind with specific region of DNA to change rate of transcription of specific gene –> change rate of synthesis of specific protein –> protein determine response of target tissue
difference between epigenetics & genetic mutation
genetic mutation: changes to nucleotide (DNA) sequence
epigenetics: methylation of DNA & changes in histone structure, affecting DNA transcription (copied to mRNA)
appetite control in humans - why is it important?
to balance energy intake with energy expenditure
