Biological Psychology

Our body is a large mass of cells which must be constantly supplied with fuel to run. We get this fuel from the food we consume, however, we do not continuously eat and there are periods of time when the digestive tract is empty. Therefore this essay will look at the biological control of eating. Although the body has short them and long term reservoirs of food, our body uses hunger signals to tell the brain when it is time to eat. There are many different reasons why this occurs and this will be explained throughout this essay.

Before the biological process to actually make the body get up and go for food, the short term and long term reservoirs begin to get used up. Within the short term reservoir, there are carbohydrates which are consumed through starchy foods such as potatoes, pasta and chips, this is stored in the cells of the liver. Food is converted into glucose within the body; some which are burnt immediately to fulfil the needs of the body there and then, others are stored in short term stores and is stored in the form of glycogen. Glucose is the only fuel used by the Central Nerve System. Short term stores feed the brain. Long term reservoirs usually built up of fat cells which have the capability to swell in size, these are inside the adipose tissue.

Metabolic signals of hunger include Ghrelin and Pradar-Willi. Ghrelin has emerged as the first circulating hunger hormone. Ghrelin has numerous functions. It is termed the ‘hunger hormone’ because it stimulates appetite, increases food intake and promotes fat storage. When administered to humans, ghrelin increases food intake by up to 30% by circulating in the bloodstream at the hypothalamus, an area of the brain crucial in the control of appetite. Recently ghrelin has also been shown to act on regions of the brain involved in reward processing such as the amygdala. Ghrelin also stimulates the release of growth hormone from the pituitary gland, which, unlike ghrelin itself, breaks down fat tissue