pathology of diabetes mellitus Flashcards
where is the endocrine function in pancreas?
Islet of Langerhans
which cells make up 2/3 in Islet of Langerhans?
B cells which secrete insulin
what is the role of insulin?
to decrease BG by driving the increase of uptake of GLC by cells
causes of type1?
not known - HLA gene associations exposure to chemicals (strepsotosin) viral infection bacteria in gut altered in infancy
function of HLA gene?
Human Leukocyte Antigen - help T cells recognise self from non-self
HLA and type1?
patients cannot distinguish own cells from foreign cells - therefore, autoimmune attack and destroying of pancreatic B cells
which cells destroy B cells?
Lymphoid cells destroy Islets of Langerhans, therefore decreasing insulin
cause of type 2?
combo of -
reduced tissue sensitivity to insulin
inability to secrete v high levels of insulin
weight and type 2?
not necessarily weight - risk is directly linked to waist size as extra fat deposited here is the danger
genetics in type 2?
variation of genes mean that some cannot produce insulin at a high rate (to counteract decreased receptor sensitivity) and so type 2 occurs
result of potbelly?
increased fatty acids in blood and therefore decreased insulin receptor sensitivity
why increased BG? (potbelly)
ineffective insulin receptors, therefore GLC isn’t absorbed into cells
how does pancreas react to less GLC uptake by cells?(potbelly)
secretes more insulin to decrease BG to restore normal homeostasis - hyperinsulinaemia
reason for not being able to produce large amounts of insulin?
having LOTS of gene variants for insulin secretion (having a few is generally okay)
how can type 2 be eradicated?
adiposity is reversible - improve diet and exercise lifestyle
long-term complications of DM?(Poorly controlled)
mortality is doubled compared to non-diabetics
MI - most common cause of death
macrovascular complications?
atherosclerosis of arteries is accelerated with DM
intima is destroyed by plaques
DM and atherosclerosis stats?
Coronary HD x2-20
MI x2-5
atherothrombotic stroke x2-3
how is atherosclerosis accelerated with DM?
LDL not removed by liver cells
- > lipoprotein and lipid stay in blood
- > hyperlipidemia
microvascular complications?
thickened wall and basal lamina in arterioles - build up of trapped albumin and collagen in endothelial cells of wall of arteriole
result of microvascular complications?
ischemia in kidney / peripheral tissues / eyes
risks of microvascular complications?
amputation x40
end stage renal disease x25
blindness x20
what is small vessel disease and what is it due to?
increased connective tissue around capillaries - due to diabetic changes
mechanism of small vessel disease?
glycosylation - reversible UNLESS there are covalent bonds (AGEs)
