Pathology of Diabetes Mellitus Flashcards
What cells within the pancreas secrete insulin?
B cells within the islets of Langerhans
How does insulin act on fat?
Insulin binds its receptor and drives glucose into adipocytes
Describe the basic pathway of glucose metabolism
Increased blood glucose causes an increased level of insulin secretion. This is turn causes an increase in the glucose uptake of cells, and decreases the levels of glucose in the serum
Describe the aetiology of type 1 diabetes mellitus
Gene defects relate to immune system, and cause the body to be unable to distinguish own cells from other cells, leading to an attack on the B cells of the pancreas. The destruction of these cells leads to decreased insulin production, resulting in increased blood glucose
What are the possible environmental triggers of type 1 diabetes mellitus?
Chemicals
Alteration of gut bacteria in infancy
Viral infections- molecular mimicry causes immune system to attack islets
Describe the aetiology of type 2 diabetes mellitus
Expanded upper body visceral fat mass results in increased levels of free fatty acids in the blood, which decreases the sensitivity of the insulin receptors. This means that more insulin is required to get the same amount of glucose into the cells, so causes hyperinsulinaemia
Describe the genetic involvement in the development of type 2 diabetes mellitus?
Some genes control whether or not you can secrete very large amounts of insulin. A variant gene may promote insulin production at low levels ONLY. If gene variations are common enough that they cannot produce high levels of insulin
What affect does diabetes mellitus have on development of atherosclerosis?
DM accelerates the development of atherosclerosis, but it does not cause it
How does diabetes mellitus cause arteriolar disease?
In diabetes mellitus, molecules flux into the subendothelial space but struggle to flux back to blood. This results in a build up of molecules under the endothelial cells, causing the basal lamina to become thickened.
Where is arteriolar disease most damaging?
Kidneys
Peripheral tissues (feet)
Eyes
Arterioles supplying nerves
What are the most common complications of arteriolar disease?
Amputation
End stage renal disease
Blindness
What are the most common complications of atherosclerosis?
Coronary heart disease
Myocardial infarction
Atherothrombotic stroke
What is the most common cause of death in diabetics?
Myocardial infarction
How does advanced glycolysation affect small vessels?
Normal collagen does not bind albumin, but glycolystaed collagen does, so albumin accumulates in the subendothelial space.
Glycolysated proteins bind their neighbouring proteins , and as cross-linked proteins cannot be removed easily the proteins persist within the arteriole walls.
