Diabetes: Science and Clinical Flashcards
The exocrine pancreas produces… [physiology]
watery, alkaline secretions and digestive enzymes to the duodenum
The endocrine pancreas has 4 groups of cells which are: [physiology]
- beta cells (insulin)
- alpha cells (glucagon)
- D-cells (somatostatin)
- F cells (pancreatic polypeptide)
Where are b-cells found? [physiology]
centrally within the islets of langerhans
Role of somatostatin [physiology]
released in response to increased BG and amino acides. slows rate of digestion to prevent excess nutrients in the plasma
Role of pancreatic polypeptide [physiology]
reduces appetite and food intake
promotes the acitivity of which enzyme [Insulin]
Glycogen synthase
inhibits the activity of which enzyme [Insulin]
lipase
[carbohydrates] insulin has 4 effects on carbohydrates
- facilitates transport into cells via GLUT 4
- stimulates glycogenesis
- inhibits glycogenolysis
- inhibits gluconeogenesis
[fat] insulin has 4 effects on fat
- increases fatty acid uptake into adipose tissue
- increased transport of glucose into adipose tissue via GLUT 4
- Promotes use of fatty acid in reactions
- inhibits lipolysis
[proteins] insulin has 3 effects on protein
- promotes active transport of amino acids into muscles
- increases amino acid incoporation into protein
- inhibits protein degradation
main driver of release of insulin [insulin; physiology]
an increase in blood sugr
5 steps of insulin release in the cell [insulin; cellular release]
- glucose enters b-cell via GLUT 2 facilitated diffusion
- glucose is metabolised to G-6-P and then to ATP
- ATP:ADP ratio increases causing ATP-K sensitive channel to close
- reduced K exit depolarises cell and opens VGCC
- Ca enters b-cell and stimulates release of insulin
insulin is produced as a polymer with what other protein [insulin]
C-peptide
*this can be measured in T1 diabetics to monitior the decrease in insulin production however may take 3-4 years to disappear so is not a reliable indicator
what is the physiological difficulty with diabetes mellitus? [DM; physiology]
An inability to produce any or sufficient endogenous insulin
Why do complications occur in DM? [DM; physiology]
As a result of high blood sugar as insulin is the only hormone able to reduce BG
Criteria for diagnosis from a random BG [DM; diagnosis]
> 11.1 mmol/L with symptoms OR
7.8 - 11 mmol/L on two occassions with symptoms
Criteria for diagnosis from 2hr OGTT [DM; diagnosis]
> 11.1mmol/L and above
7.8-11 is pre-diabetes
Criteria for diagnosis from FG [DM; diagnosis]
> 7.0mmol/L
Criteria for diagnosis from HbA1c [DM; diagnosis]
48 mmol/L and above
Three forms of microvascular complications [DM; complications]
Retinopathy, neuropathy, nephropathy
Process underlying retinopathy [DM; Complications]
- formations of microaneurysms in the eye.
2. proteins cause the BM of the eye to become thickened and more permeabel –> fibrous response –> destroys the retina
Process underlying nephropathy [DM; Complications]
Vascular disease in the kidney leads to kidney failure
Process underlying neuropthy [DM; Complications]
PVD may affect the nerves causing a loss of sensation and higher chance of foot ulcers
Forms of macrovascular complications [DM; Complications]
MI, Stroke and CVD - need to tightly control blood pressure as all vascular disease is accelerated, 50-70% of diabetics die from CVD
Pathophysiology of T1DM [T1DM]
Autoimmune destruction of the pancreatic b-cells leading to inability to produce insulin and control blood sugar. Usually occurs in adolescence but can occur at any age
Genetics associated with T1DM [T1; Science]
90% of T1DM carry HLA DR3+DR4; those with a first degree relative with T1DM have a 5-6% chance of developing the disease
Autoantibodies associated with T1DM [T1; science]
ICA (islet cell antibodies) and GAD (anti-glutamic acid decarboxylase)
What is LADA? [T1; science]
A form of T1 that presents in adults but presents with a slower onset and slower progression to insulin dependence
Symptoms associated with T1 (5/9 for 5*) [T1; symptoms]
Polyuria; polydipsia; weight loss; tiredness; ketosis; thirst; thrush; many and persistent infections; blurred vision
Treatment of T1 [T1; Treatment]
Insulin regimes, DAFNE
Example of long acting insulin [T1; treatment]
lantus
Example of rapid acting insulin [T1; treatment]
novorapid
A finger prick before a meal informs the patient of the long/short acting dose? [T1; treatment]
A long acting dose is monitored before a meal
A finger prick after a meal informs the patient of the long/short acting dose? [T1; treatment]
A short acting dose is monitored after the meal
What sort of adjustment might be made to insulin when exercising for a short period and why? [T1; treatment; physiology]
Increased dose of insulin as a short burst of exercise will increase the amount of adrenalin produced. Adrenaline pushes BG up and thus more insulin is required to counteract this.
What sort of adjustment might be made to insulin when exercising for a longer period and why? [T1; treatment; physiology]
Decreased dose of insulin as the prolonged exercise will deplete BG availability and thus less insulin is required
What sort of adjustment might be made to insulin when feeling unwell and why? [T1; treatment; physiology]
More insulin is likely to be required especially if the patient is not eating or is vomiting and becoming dehydrated. This is because the stress hormone cortisol is produced in higher quantities and is likely to push BG up. Not controlling insulin properly when unwell is more likely to result in DKA
What is ketoacidosis? [T1; phsyiology]
ketoacidosis is an alternative pathway used in the starvation states in order to produce energy. It is less efficient and produces acetone as a by-product.
What is diabetic ketoacidosis? [T1; physiology; complications]
In T1DM, blood glucose may be high, glucose cannot enter the cells without insulin. Thus the cells act as if in starvation state and use the ketosis pathway to generate energy