regulating blood glucose

• hyperglycaemia 


  • blood glucose level too high
  • produces insulin from beta cells
  • glucose converted into glycogen using insulin - glucose moves in blood into liver and muscles
  • glucose levels decrease
• action of insulin on liver cells

  • tertiary structure changes/conformational change
  • insulin receptors found on surface of liver cells, some muscle cells

  
• glucagon


  hormone released by alpha cells in response to low blood sugar levels. It increases the production of glucose from glycogen
• gluconeogenesis 


  production of glucose from non-carbohydrate sources such as amino acids and lipids
• glycogenolysis 


  breakdown of glycogen into glucose (by phosphorylase A)
• insulin


  hormone released by beta cells in response to high blood glucose levels. it causes the uptake of glucose and its conversion to glycogen
• alpha and beta cells


  cells in islets of Langerhans in the pancreas which secrete glucagon and insulin
• glycogenesis 


  conversion of glucose into glycogen for storage
• what can change blood glucose concentration 


  • eating
  • respiration
  • activity levels
  • starvation/ time between eating
  • dehydration
  • side effects of some medication
  • short/ long term pain
  • alcohol
• hyperglycaemia 


  • above 6 mmol md-3
  • can lower water potential of blood and cause dehydration
  • if persistent, can cause organ failure
• hypoglycaemia 


  • below 4 mmol md-3
  • reduced delivery of glucose to cells/ tissues especially in brain
  • tiredness
  • seizures, unconsciousness and death
  • if prolonged, can cause impairment of brain function and confusion
• normal blood concentration = 4-6 mmol md-3
• negative feedback - control of blood glucose concentration