endocrine- pancreatic disorder: diabetes Flashcards
diabetes is the most common
endocrine disorder
normally what do beta and alpha cells do in the pancreas?
beta cells produce insulin
alpha cells produce glucagon
where are the beta cells
islet of langerhans in the pancreas
in diabetes there is hypoactivity of?
insulin
-either SECRETION or ACTION of insulin is defective
absolute deficiency of insulin-
absent insulin or very little
relative defiency of insulin-
insulin present but not effective
type 1 diabetes?
approx 10%
absolute insulin deficiency
BETA CELLS are DAMAGED by autoimmunity or ABSENT
type 1A
- immune mediated (90-95%)
- autoimmune destruction of beta cells
type 1B
not autoimmune (5-10%) -idiopathic destruction of beta cells
LADA=
latent autoimmune diabetes of the adult
-type 1 developing gradually and appearing later in life
type 2 diabetes?
less severe, beta cells can still produce insulin, receptors do not respond to insulin
MODY=
maturity onset diabetes in the young- type 2 diabetes developing early in life d/t poor lifestyle
gestational diabetes=
hyperglycaemia during pregnancy, normal after
drug-induced diabetes?
example, from steroids
etiology of t1 and t2?
complex trait- polygenic, multiple defective genes and environmental factors
etiology of t1?
- MHC genes on chromosome 6 (40% have defective MHC genes)
- code for proteins that sit on the surface of cells to show them pathogens (so defence cells can recognize)
- MHC bind to peptide fragments of pathogens and display them on the cell surface for recognition of T cells
- MHC II on antigen presenting cells (such as DC, B cells, macrophages) presents extracellular peptides
- MHC I holds self-antigens identifying the cell (presents intracellular peptides
- some viruses reduce amount of MHC 1, so they can hide from defence cells and not be detected as foreign, NK cells destroy all cells with reduced MHC 1 in response
- OR insulin gene on chromosome 11 (10%have defective insulin gene)—> codes for a protein that regulates division and function of beta cells, impacts insulin production
- OR t cell hypersensitivity to beta cell antigen
- FAMILIAL risk as well!! 10x morelikely
etiology of T2 diabetes
- strong unclear genetic component
- MODY
in MODY 50% of cases it is… which gene
glucokinase gene on chr 7 that is affected
- codes for protein (glucokinase enzyme)
- glucose + phosphate is said to be phosphorylated, which allows glucose to be converted into glycogen and stored
- phosphorylation is brought on by glucokinase, but if gene coding this liver enzyme is defective—> glucose will be taken in by insulin but go right back into bloodstream
prediabetes tests/signs?
- impaired fasting glucose
- glucose tolerance test
- impaired HbA1c
impaired fasting glucose-prediabetes?
6.1-6.9 mmol/L
-overnight fast, BG feasured
normal is 3.5-5.5
Glucose tolerance test?
2 hour oral glucose tolerance test (ingest glucose and monitor plasma levels for 2 hours) if it does not return to normal (7.8-11mmol/l) after 2h pt has prediabetes
-if they have above 11: diabetes
impaired HbA1c?
-6-6.4% is prediabetes
A1c is a subclass of Hba (adult hemoglobin)
-measure of glucose binding to hemoglobin, more will bind if higher levels of glucose
metabolic syndrome effect on diabetes? features?
- predisposes individual to CV disease and type 2 diabetes
- 70% of ppl w it have type 2
- features: abdominal obesity, htn, hyperlipidemia, IFG, IGT, insulin resistance