Pancreas and its Disorders - Practice Questions & MCQ

• The pancreas is derived from the endoderm.
• It is present below the stomach in the bend of the stomach.
• The pancreas is a composite gland which acts as both exocrine and endocrine gland. 
• The endocrine pancreas consists of ‘Islets of Langerhans’. 
• There are about 1 to 2 million Islets of Langerhans in a normal human pancreas representing only 1 to 2 percent of the pancreatic tissue. 
• The types of cells in the Islet of Langerhans are: 
  • α-cells: secrete glucagon
  • β-cells: secrete insulin
  • Delta cells: secrete somatostatin
  • Pancreatic Polypeptide Cells or F-Cells: secrete pancreatic polypeptide

Hormones of Pancreas and Their Role:

1. Glucagon:

• It stimulates the liver to convert stored glycogen into glucose. 
• It is antagonistic to the insulin.
• Glucagon acts on the cells of the liver and adipose tissue

2. Insulin

• It mobilises glucose from bloodstream into fat, muscle and liver cells
• It stimulates liver and muscle tissue to store excess glucose as Glycogen
• It also lowers blood glucose levels by lowering glucose production in liver (gluconeogenesis)
• It inhibits Glycogenolysis (breakdown of Glycogen)  

3. Somatostatin:

• It is the same substance as growth-inhibiting hormones from the hypothalamus.
• One of the actions of somatostatin seems to suppress the release of other hormones from the pancreas. 
• It also appears to suppress the release of hormones from the digestive tract.
• It acts on the cells of the pancreas   

  4. Pancreatic Polypeptide (PP):

• Pancreatic polypeptide inhibits the release of digestive secretion of the pancreas. 
  
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Diabetes mellitus (Hyperglycemia):

• The insulin-dependent diabetes mellitus (IDDM) is caused by a failure of the Beta-cells to produce an adequate amount of insulin.
• The non-insulin-dependent diabetes mellitus (NIDDM) appears to involve the failure of insulin to facilitate the movement of glucose into cells.
• In both disorders, the blood glucose concentration is elevated above the normal range.
• Some of the glucose is excreted in the urine, and water follows the glucose, causing excessive urination and dehydration of body tissues. 
• This causes excessive thirst (polydipsia). 
• The cells are unable to utilize glucose and other carbohydrates for energy production.
• They utilize their proteins for it. The person becomes very weak. 
• Degradation of fats increases, producing ketone bodies (ketosis). 
• The latter are acidic and poisonous. 
• Blood cholesterol level rises. Healing power is impaired.
• A tendency towards non-insulin-dependent diabetes appears to be inherited as an autosomal recessive characteristic.

Hypoglycemia:

• It occurs when the blood glucose level falls below normal. 
• It may be caused by an excess of insulin, a deficiency of glucagon, or a failure of the secretion of the two hormones to completely regulate the blood sugar.
• Symptoms of hypoglycemia include weakness, profuse sweating, irritability, confusion, unconsciousness and convulsions. It needs an urgent intake of sugar or glucose.