Pancreas Flashcards
Describe the structure of the pancreas
lobular structure beneath stomach
What are the 2 types of cells of the pancreas?
- acini
- islets of Langerhans (IoL)
What are acini?
groups of exocrine cells secreting into pancreatic ducts
What are the islets of Langerhans (IoL)?
groups of endocrine cells
What is the exocrine function of the pancreas?
secretion of alkaline pancreatic juice containing digestive enzymes
What is the endocrine function of the pancreas?
secretion of hormones (important for glucose homeostasis)
List the pancreatic hormones
- insulin
- glucagon
What type of molecule are the pancreatic hormones?
polypeptide hormone
What is insulin secreted by?
synthesized & secreted by β-cells of the islets of Langerhans
Why is insulin produced after feeding?
in response to:
- high blood glucose & amino acids
- gastrointestinal hormones
- parasympathetic nerve stimulation
What inhibits insulin?
- sympathetic nerve stimulation via α2-adrenoceptors
- somatostatin from pancreatic δ-cells
What is glucagon secreted by?
synthesized & secreted by α-cells of the islets of Langerhans
Why is glucagon produced?
in response to:
- low blood glucose
- high blood amino acids
- gastrointestinal hormones
- parasympathetic & sympathetic nerve stimulation
What is glucagon inhibited by?
- insulin from pancreatic β-cells
- somatostatin from pancreatic δ-cells
What is the value of normal blood glucose?
3.5-6.0 mM
What is hyperglycaemia and what causes it?
increase in blood glucose caused by:
- meal
- release of insulin
- changes in metabolism
What is hypoglycaemia and what is it caused by?
decrease in blood glucose caused by:
- stress, fasting, exercise
- release of glucagon, catecholamines, GH, cortisol
- inhibition of insulin secretion
- changes in metabolism
What is Diabetes Mellitus?
inability to regulate blood glucose within normal range
- type 1
- type 2
- gestational
What is type 1 diabetes?
- insulin deficiency
- onset in juvenile life
- fatal without insulin treatment
What is the insulin deficiency in type 1 diabetes caused by and how is it treated?
- autoimmune destruction of β-cells in pancreas
- treated: insulin injection, infusion pump
What is type 2 diabetes?
- insulin resistance
- onset in later life
- maybe obesity or pregnancy
What is type 2 diabetes caused by and how is it treated?
Defect in insulin signalling systems in target tissues (lifestyle, medical & genetic factors), treated by:
- healthy diet
- increased physical activity
- medication
- insulin (if needed)
What are symptoms of diabetes mellitus?
- hyperglycaemia (high blood glucose)
- glycosuria
- polyuria (excessive urination)
- polydipsia (water loss → dehydration + thirst)
- polyphagia (excessive hunger)
What is glycosuria?
- high filtered load of glucose at kidney
- can’t be reabsorbed totally in renal tubules
- excreted in urine
