• Negative feedback occurs when conditions change from the ideal or?set point?and returns conditions to this set point
• It works in the following way:
  • if the level of something?rises, control systems are switched on to?reduce it?again
  • if the level of something?falls, control systems are switched on to?raise it?again

   

• Negative feedback mechanisms are usually a continuous cycle of bringing levels down and then bringing them back up so that overall, they stay within a?narrow range?of what is considered ‘normal’

The negative feedback cycle

• Blood glucose levels are controlled by a negative feedback mechanism involving the production of two?hormones?-?insulin?and?glucagon
• Both hormones which control blood glucose concentration are made in the?pancreas
• Insulin?is produced when?blood glucose rises?and?stimulates liver and muscle cells to convert excess glucose into glycogen to be stored
• Glucagon?is produced when?blood glucose falls?and?stimulates liver and muscle cells to convert stored glycogen into glucose to be released into the blood

Negative feedback regulation of blood glucose levels

• Type 1 diabetes?is a condition where the blood glucose levels are not able to be regulated as the?insulin-secreting cells in the pancreas are not able to produce insulin
• This means that blood glucose levels are often?far too high
• It can be treated by?injecting insulin
• The extra insulin causes the liver to convert?glucose into glycogen, which?reduces?the blood glucose level
• Symptoms?of diabetes include extreme thirst, weakness or tiredness, blurred vision, weight loss and loss of consciousness in extreme cases
• People with Type 1 diabetes have to?monitor?their blood glucose levels throughout the day as their levels of?physical activity?and their?diet?affect the amount of insulin needed
• They can help to?control?their blood glucose level by being careful with their?diet?-? eating foods that will not cause large increases in blood glucose level, and by?exercising, which can lower blood glucose levels due to increased respiration in the muscles