In this post, we will discuss the physiology of appetite in a short as it is a frequent source of MCQs on PG examinations.
Physiology of appetite
- The arcuate nucleus (ARC) is a key hypothalamic nucleus in the regulation of appetite and is involved in integrating peripheral satiety and adiposity signals via orexigenic and anorexigenic neuropeptide transmission to other hypothalamic and extrahypothalamic brain regions.
- Proximity of ARC to the median eminence and the fact that it is not fully insulated from the circulation by the blood brain barrier makes it strategically positioned to integrate the great number of peripheral signals controlling food intake.
- There are two major neuronal populations in the ARC implicated in the regulation of feeding:
- One population co-expresses Neuropeptide Y (NPY) and agouti-related protein (AgRP) and increases food intake. These are called orexigenic neurotransmitters.
- The second population of neurons co-expresses cocaine- and amphetamine-related transcript (CART) and proopiomelanocortin (POMC), the precursor to the melanocortin receptor agonist, α melanocyte-stimulating hormone (α-MSH) and inhibits food intake. These are called anorexigenic neurotransmitters.
– Please follow the rest in the following pictures.
General physiology of appetite: (at times of low and high body energy stores)
Figure 2: Hormones involved in appetite:
Figure 3: Another picture showing preferential pathway towards anorexia just after a meal:
Figure 4: The short form of Figure 3.
Hope this post will help you understanding the physiology of appetite in a short time. Thank you.