When our bodies need nourishment to function properly neurotransmitters are released, Neuropeptide Y (NPY) has been noted by scientists as an important neurotransmitter involved in sending messages to and from different parts of the brain. Furthermore, scientists have identified two chemicals Ghrelin and Leptin that communicate with NPY and are involved in hunger signalling. When our bodies have used up all the fuel from previous food consumed it signalls to the brian that it is time to eat. This process starts in the stomach, where Ghrelin is secreted. When our bodies have used up the nutrients from food and our blood and insulin levels are low. The ‘hunger hormone’ Ghrelin communicates with the hypothalamus in the brain via the vagus nerve. The hypothalamus is the part of the brian that is responsible for regulating normal body functions; thirst, sleep and sex drive. When the brain receives the communication from Ghrelin, the Hypothalamus triggers the release of Neuropeptide Y – which stimulates our appetite and signals feelings of hunger.In order to be able to continuously provide the cells of the body with fuel the body stores fuel in both a short-term (STR) and a long term reservoir (LTR). Food is turned into glucose -the STR stores any glucose that has not been immediately used by the body’s metabolism. The remainder of the glucose is stored and converted to fat at the liver, it is then transported as adipose tissue. The last fraction is converted to glycogen and held at the liver and lean muscles. The fat-filled adipose tissue makes up the LTR, the adipose absorbs nutrients from the blood and stores them Triglycerides which are broken up into fatty acids used by all cells (expect CNS cells) and glycerol which is converted back to glucose and used by CNS. The rate at which the cells in the nervous system use up the fuel is referred to as metabolism.
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