The Regulation Of Blood Glucose

Question 1

Describe the histology of the Pancreas and outline its role as an endocrine and exocrine gland

Answer 1

• An organ which is both an Endocrine gland and an Exocrine gland
• Cells with an EXOCRINE function (acinar cells) are found in clusters around the pancreatic duct - secrete digestive enzymes into the pancreatic duct, they are then carried in fluid to the small intestine
• cells with an ENDOCRINE function (islet of langerhans) are made up of alpha and beta cells

     - found in clusters around blood capillaries 
     - secrete hormones directly into the blood 
     - a cells - manufacture and secrete glucagon 
     - B cells - manufacture and secrete insulin

Question 1

What happens if blood glucose rises

Answer 1

• Detected by Beta Cells in the Islet of Langherans (IoL)
• Beta Cells secrete Insulin into the blood
• Insulin binds to receptors on hepatocytes
• Muscle Cells take up Glucose and convert it to Glycogen or use it in respiration.
• Hepatocytes take up Glucose and convert it to Glycogen (GLYCOGENESIS)
• Blood Glucose levels fall back normal levels

Question 2

What happens when Blood Glucose concentration falls

Answer 2

• Detected by Alpha Cells in the Islet of Langherans (IoL)
• Alpha Cells secrete Glucagon into the blood
• Glucagon binds to receptors on Hepatocytes
• Hepatocytes releases Glucose by Glycogenolysis.
• Glycogen ▶️ Glucose (GLUCONEOGENESIS)
• Making new Glucose from Amino Acids
• Glucose is released into the blood
• Blood Glucose levels rise back normal levels