Endocrine disorders Flashcards
causes of hypersecretion
- secretory tumor
- increased trophic stimulation
- defective negative feedback loop
causes of hyposecretion (and examples)
- no trophic stimulation (atrophy)
- receptor defect (nephrogenic diabetes insipidus)
- immune disorder (autoimmunity)
- suppressive therapy (overcorrection; hyper to hypo)
- dietary deficiency (iodine for thyroid)
- metabolism defect (missing enzyme)
In the islets of langerhans, beta cells produce ____ and alpha cells produce _____
insulin
glucagon
what is diabetes mellitus
defective insulin secretion and/or action
what are the 2 types of insulin deficiency
- absolute deficiency (absent/little produced)
- relative deficiency (present but ineffective)
type 1 diabetes mellitus is what type of deficiency
absolute
what type of diabetes mellitus is early onset
type 1
what are the 2 types of type 1 diabetes mellitus and what are their cause and prevalance
1A: immune-mediated: 90-95%
1B: idiopathic: 5-10%
what % of diabetes mellitus is type 1
10%
what % of diabetes mellitus is type 2
90%
type 2 diabetes mellitus is what type of deficiency
relative
what is LADA
latent autoimmune diabetes in adults
type 1A manifesting in adults
what is MODY
maturity-onset diabetes in the young
type 2 in the young d/t poor lifestyle
diabetes mellitus is what type of genetic abnormality
complex trait (multifactorial) genetics + environment
type 1 diabetes mellitus has what type of risk
familial risk (10x)
causes of type 1 diabetes mellitus
- defective insulin gene on chromosome 11
- T cell hypersensitivity to beta cell Ag
- defective MHC genes on chromosome 6
40% of type 1 diabetes mellitus is caused by
defective MHC genes on chromosome 6
the insulin gene on chromosome 11 codes for
a protein that regulates division and functioning of beta cells (therefore insulin secretion)
how does a defective MHC gene cause type 1 diabetes mellitus
beta cells are recognized as foreign, Ab’s target and destroy them
type 2 diabetes mellitus has a strong but ______ genetic involvement
unclear
50% of type 2 diabetes mellitus is caused by
a defective glucokinase gene on chromosome 7
the glucokinase gene codes for
a protein called glucokinase enzyme which is responsible for phosphorylation
what is phosphorylation
when glucose enters a cell and attaches to phosphate it becomes phosphorylated and cannot leave the cell
what are the criteria for prediabetes
- IFG (impaired fasting glucose) 6.1-6.9
- IGT (impaired glucose tolerance) 7.8-11
- HbA1C 6-6.4%
what is a fasting glucose test
testing after a 10 hour fast
what is a normal fasting glucose test range
3.5-5.5
what is a glucose tolerance test
fasting, oral glucose solution give, monitor BG for 2 hours
what does HbA1C measure
the 1C form of Hb
glucose binds HbA1C d/t
high affinity
what does metabolic syndrome predispose someone to
CVD
type 2 diabetes mellitus
parameters of metabolic syndrome
- IFG
- IGT
- insulin resistance
- hyperlipidemia
- abdominal obesity
- HTN
in type 1 diabetes mellitus with a defective MHC gene, Ab’s target
self-antigens on the surface of beta cells and islet cells
in type 1 diabetes mellitus with T cell hypersensitivity, T cells infiltrate ______ causing ______
islets of Langerhans, causing insulitis
what is insulitis
inflammation of the islets of Langerhans
what are the 4 types of relative insulin deficiency in type 2 diabetes mellitus
- delayed secretion
- target cell problem
- insulin resistance
- hepatic glucogenesis
in type 2 diabetes insulin levels are
normal, high, or low
in type 1 diabetes, insulin levels are
low and none at all
how is degree of damage determined in type 2 diabetes mellitus
amyloid deposits in the islets of Langerhans
in type 2 diabetes mellitus, increased hepatic glucose output is caused by
a perceived lack of glucose d/t mutated glucokinase preventing phosphorylation
in type 2 diabetes mellitus, there is decreased glucose uptake due to
mutated glucokinase preventing phosphorylation
insulin deficiency (absolute/relative) causes
impaired glucose utilization and increased hepatic glucogenesis d/t a perceived lack of glucose
when hyperglycemia occurs, ____ is exceeded causing ______
the renal threshold for glucose causing glucosuria
glucosuria causes what to increase
osmotic pressure in the filtrate
increased osmotic pressure in the filtrate causes increased ________, causing ____
fluid movement to the filtrate, causing polyuria
polyuria causes ____ and ____
dehydration and polydipsia
once above the renal threshold everything else will be ___
excreted
impaired glucose utilization by cells will cause
increased mobilization and use of lipids and proteins
mobilization and use of lipids and proteins will increase what
metabolites in the blood (ketones)
elevated levels of ketones cause
ketonuria
manifestations of diabetes mellitus
3 P's: - polyuria - polydipsia - polyphagia type 1: weight loss type 2: obesity complications
why does type 1 diabetes mellitus cause weight loss
d/t glucose not being stored
why is insulin not take PO
because it is a hormone and also a protein that will be broken down by enzymes in the stomach
hypoglycemia is more frequent in type _ DM because
1
they are taking insulin injections