Appetite, Metabolic Syndrome And DOHD Flashcards
Describe how the location of the arcuate nucleus is ideal for controlling appetite
- Located at base of hypothalamus
- Can sense substances such as appetite hormones from bloodstream e.g. Ghrelin, fatty acids, Leptin
Explain how the primary neurones in the arcuate nucleus control appetite
- 2 types: excitatory and inhibitory
- Excitatory neurones contain NPY and AgRP which promote HUNGER
- Inhibitory neurones contain POMC (yields neurotransmitters α-MSH and β-endorphin) which promote SATIETY
Describe how feeding behaviour can be altered
Primary neurones synapse with secondary neurones in other regions of the hypothalamus and the signals are INTEGRATED
What 2 substances promote hunger?
- NPY (neuropeptide Y)
- AgRP (Agouti-related peptide)
What substance in the inhibitory primary neurones promote satiety?
- POMC (pro-opiomelanocortin)
- Yields several neurotransmitters including α-MSH and β-endorphin (involved in pleasure)
What hormone detected in the arcuate nucleus promotes hunger and where is it released from?
- GHRELIN
- Released from stomach wall when empty
- Stimulates excitatory primary neurones in arcuate nucleus, promoting hunger
- Filling of stomach inhibits release of ghrelin
What hormone released in the colon promote satiety?
- PEPTIDE TYROSINE TYROSINE (PYY)
- Short 36AA peptide released from ILEUM OF COLON in response to feeding
- Stimulates inhibitory primary neurones and inhibits excitatory primary neurones
- SUPPRESSES APPETITE
Describe the affect of LEPTIN on appetite
- Released by adipocytes
- Stimulates inhibitory primary neurones (POMC)
- Inhibits excitatory primary neurones (NPY and AgRP)
- SUPPRESSES APPETITE
Explain the action of LEPTIN in mitochondria
- Induces expression of UNCOUPLERS - uncouple electron transport from ATP synthesis
- Increases permeability of inner membrane to H+
- Energy from PMF is dissipated as heat
Name 4 hormones that suppress appetite
- PYY
- Leptin
- Insulin
- Amylin
Define METABOLIC SYNDROME
A group or recognisable pattern of symptoms or abnormalities that indicate a particular trait or disease
- CLUSTER of the most dangerous risk factors associated with cardiovascular disease
What risk factors may be associated with metabolic syndrome/CVD?
- Abdominal obesity
- High blood pressure
- Insulin resistance
- High fasting plasma glucose
- Dyslipidaemia (⬇️HDL cholesterol, ⬆️TAGs)
Describe the aetiology of metabolic syndrome
- Exact underlying cause UNKNOWN
- Insulin resistance and abdominal (central) obesity are significant risk factors
Explain how insulin resistance can cause metabolic syndrome
- Cells less sensitive to insulin so glucose is not efficiently utilised
- High plasma glucose leads to increased insulin production and eventually β cells wear out
- Type II diabetes
- Risk of micro/macrovascular damage due to glycosylation of vessels
Describe the treatment methods associated with metabolic syndrome
- PRIMARY methods include change to diet and lifestyle by moderate calorie restriction and increase daily exercise
- SECONDARY methods (when primary methods are unaffective) involves drug intervention e.g. Statins. anti hypertensive drugs (lower BP) and antidiabetic drugs (lower BG)
