Control of appetite Flashcards
Where is the appetite centre?
In the Arcuate nuclei in the Hypothalamus
What is the Arcuate nuclei made of?
Primary neurones (sense metabolites and hormone levels) Secondary neurones (Synthesise input and co ordinate a response via the Vagus nerve)
What are the 2 groups of primary neurones?
Excitatory (stimulate appetite using NPY)
Inhibitary (suppress appetite using POMC)
What is POMC?
A prohormone which can be cleaved into Beta endorphin, ACTH and alpha MSH
How is POMC involved in the feedback system?
When the stomach is full there is POMC release in the brain to suppress appetite. Leads to Beta endorphins being release so there is a feeling of euphoria and tiredness.
What is Ghrelin?
Peptide hormone released from the wall of an empty stomach
Activates stimulatory neurones, therefore increases appetite
What is Leptin?
Released from adipocytes
Stimulates inhibitory neurones
How does Leptin encourage heat loss instead of ATP production?
It induces expression of uncoupling proteins in mitochondria
How has Leptin been linked to Obesity?
May be a lack of Leptin
May be Insensitivity to Leptin
What is PYY?
Peptide hormone released from the wall of the small intestine. It reduces appetite
How is Insulin related to body weight?
It is thought to control long and short term weight and decrease appetite in the same way as Leptin
Define metabolic syndrome?
Group of symptoms including insulin resistance, dyslipidaemia, glucose intolerance and hypertension associated with central adiposity
How did metabolic syndrome arise?
Observation of a common pattern of symptoms in obese people
What are the major factors which predispose to Insulin resistance?
Obesity
Sedentary lifestyle
What is a dyslipidaemic profile?
High VLDL
High LDL
Low HDL
