Pathology of DM Flashcards
What are the 2 types of DM?
Type I and Type II
What is the arrangement of tissue in the pancreas?
Acinus
What are present in pancreas histology?
Islet of langerhans
What do islets of langerhan make up?
Endocrine pancreas
What do B cells secrete?
Insulin
What type of cell are most cells in islet of Langerhans?
B cells
Where do B cells secrete insulin?
Into the capillaries
What stimulates the release of insulin?
Intake of food
Converted to glucose
Stimulates insulin production
Where does insulin bind?
To its receptors
What does insulin allow?
Glucose to be taken up by the cells
What does insulin decrease?
Serum glucose
What causes Type I DM?
Not entirely known
Autoimmune response by failure of T cells to recognise self from non slef
What can sometimes be seen years later on histology in type I patients?
Scarred islets
What is the viral theory behind the aetiology of type I DM?
Though that the surface of B cells mimics that of a virus antigen causing an immune attack
What causes type II diabetes?
Combination of reduced tissue sensitivity to insulin
Inability to secrete very high levels of insulin
Which type of weight gain is bad for type II diabetes?
Expanded upper body visceral fat mass
Are pear shaped woman at risk of type II?
No
What causes gain in body fat? (simple terms)
increased energy intake
Decreased energy output
What is the response of the pancreas to a decreased insulin receptor sensitivity?
To secrete more insulin
Why does the pancreas need to secrete more insulin in type 2?
Because there is a decreased removal of glucose from the blood to the tissues
What does central adiposity lead to?
Hyperinsulinaemia
When will diabetes not occur with decreased insulin sensitivity?
When insulin production can increase at the same rate
What controls increased and increased insulin production by B cells?
Genes
What happens in type II diabetes?
There is eventually not enough insulin production to counteract the decreased receptor sensitivity
What is the commonest cause of death in type 2?
MI
Is type II reversible?
Yes with weight loss
What are the 2 main groups of complication from DM?
Microvascular
Macrovascular
What is DM a major risk factor for?
Atherosclerosis
- CHD
- MI
- Stroke
What is one mechanism by which DM accelerates atherosclerosis?
Glc attaches to LDL Prevents I attaching to its receptor Prevents excretion by the liver Stays in the blood Hyperlipidaemia Leading to atherosclerosis
What is between the basal lamina and endothelial cells?
Potential space
What happens in microvessels in DM?
Molecules flux into subendothelial space but then find it hard to flux back into the blood
Build up of trapped molecules under endothelial cells
What happens to the BL in DM?
Thickens
Which tissues are particularly damaged with small vessel disease?
Kidneys
Peripheral tissues
Eyes
What is the relative risk of amputation with DM?
40 x
What is the increased risk of renal disease in DM?
25 x
What is the increased risk of blindness?
20x
How do molecules get trapped under epithelium in DM?
Glycosylated collagen trapping albumin
or
Glycosylated BL proteins creating rigid cross linked proteins that can not be removed
When do complications most likely occur in DM?
When there is prolonged poor control
