PSYA3 Neurological Mechanisms in Eating

HideShow resource information
  • Created by: John
  • Created on: 04-05-13 17:06

(AO1)

There is a complex web of Neurological Mechanisms that play a role in controlling eating and hunger.

One of these mechanisms involves the HYPOTHALAMUS...

(http://www.visualphotos.com/photo/1x6009481/brain_ventricles_and_thalami_coloured_ct/mri_scan_p330333.jpg)

  • Hypothalamus has TWO PARTS that work in opposition to each other.
  • This is called the DUAL PROCESS MODEL.
  • The VENTROMEDIAL HYPOTHALAMUS (VMH) is called the 'satiety centre' and stops eating when we are full by monitoring stomach content levels and contractions through the vegus nerve.
  • The LATERAL HYPOTHALAMUS (LH) is called the 'feeding centre' and makes us eat when blood sugar levels drop.
  • The HYPOTHALAMUS works to maintain homeostasis in the body, so if a person has too many nutrients VMH is activated, and if too few nutrients LH is activated.

...

However the LH can be linked to two further parts of the Hypothalamus...

  •  ARCUATE NUCLEUS (ARC)
  •  PARAVENTRICULAR NUCLEUS (PVN)

The ARC consists of Hunger Neurones and Satiety Neurones

...

In Hunger Neurones...

  • GHRELIN is a hunger hormone produced in the stomach (thought to cause the contraction feelings we experience during hunger)
  • This stimulates the vegus nerve
  • Which then stimulates  hunger neurones in ARC
  • TASTE cells send neural signals to hunger neurones in ARC when tasty food is detected.

THEN...

  • The Hunger Neurones in ARC send a chemical message (NPY and AgRP) to the PVN
  • This stimulates PVN to send nerve impulses to the LH
  • LH to releases Orexin which stimulates food seeking behaviour.

...

In Satiety Neurones...

  • CHOLECYSTOKININ (CKK) is released during distension of the intestines, and stimulates satiety neurones in ARC. (Short Term)
  • GLUCOSE levels in the blood are monitored by nerve cells, which then stimulate satiety neurones in the ARC
  • LEPTIN is released by body fat which stimulates the satiety neurones in ARC. (Long Term)

THEN...

  • The Satiety Neurones in ARC release Melanocortin
  • This inhibits the action of NPY and AgRP
  • So hunger is not experienced

~~~~~~~~~~~~~~~~~~~

(AO1)

Another neural mechanism involves NEUROTRANSMITTERS...

(http://www.primalbody-primalmind.com/wp-content/uploads/2009/07/neurotransmitter_home1.gif)

  • Neurotransmitters (chemicals in the brain) may be linked to the PARAVENTRICULAR NUCLEUS (PVH…

Comments

No comments have yet been made

Similar Psychology resources:

See all Psychology resources »See all resources »