Diabetes Flashcards
What is the pancreas and what does it secrete?
-is an endocrine and exocrine gland
-secretes several enzymes into duodenum for digestion (exocrine)
-secretes insulin when glucose increases, glucagon when glucose decreases (endocrine)
Which pancreatic cells secrete insulin and glucagon?
-alpha = glucagon
-beta = insulin
What is the islet of Langerhans in the pancreas?
group of cells that secrete hormones into blood (endocrine)
What is the pathway when blood glucose is high?
high blood glucose -> beta cells in the pancreas release insulin -> liver produces glycogen and cells take up glucose -> blood glucose decreases and no stimulus to release insulin
What is the pathway if the blood glucose is low?
low blood glucose -> alpha cells in the pancreas release glucagon -> liver breaks down glycogen -> blood glucose rises and no stimulus to release glucagon
What is glucose homeostasis?
-the reciprocally regulated pathways of glycolysis and gluconeogenesis
- When blood sugar rises, liver combats
-when blood sugar decreases, the liver combats
-keeps the blood sugar relatively steady (90mg/100mL)
What is type 1 diabetes?
-develops suddenly and in young people
-no functional beta cells from autoimmune destruction by T-cells
-does not secrete insulin
-causes episodic hyperglycemia
-10% of primary cases
What is type 2 diabetes?
-occurs in older people
-insulin resistance or deficiency in secretion
-insulin levels are normal or elevated because the body compensates because they are not responding
-also causes hyperglycemia
-90% of primary cases
What is diabetes mellitus?
-a group of metabolic diseases-caused by elevated glucose levels
What is primary diabetes mellitus?
-95% of cases
-type 1 and type 2
What is secondary diabetes mellitus?
-5% of cases
-as a result of a disease or medication
caused by:
-endocrine diseases
-chronic pancreatitis
-cushing’s syndrome
How is type 1 diabetes controlled?
-insulin injections
-prevents hyperglycemia and ketoacidosis
-mimic basal and reactive insulin secretions to respond to glucose levels
How is type 2 diabetes controlled?
-diet change and exercise
-block liver glucose production
-maintain glucose levels
-prevent long-term complications
What factors can lead to type 2 diabetes?
-genetics
-aging
-peripheral insulin resistance
-diet
What organs can sense insulin?
-liver
-muscle
-adipose tissue
What do the insulin-sensing organs do when they are resistant to insulin?
-pancreas -> beta cell disfunction
-liver -> increased glucose output (no insulin to stop it)
-muscle -> decrease in glucose uptake
-adipose tissue -> exaggerated lipolysis
List some signs/symptoms of hyperglycemia
-fasting glucose of >6.5 mmol/L
-polyuria (increased pee)
-polydipsia (thirst)
-glucosuria (peeing glucose)
-weight change
-fatigue
What are the long-term complications of hyperglycemia?
-hypertension
-glaucoma
-hemorrhage
-gangrene
-infections -> amputations
-peripheral neuropathy
-pyelonephritis
What are the two groups of long-term diabetes complications?
-macrovascular: Complications of large and medium-sized vessels ex. stroke, coronary heart disease
-microvascular: complications of small vessels ex. retinopathy, neuropathy
What occurs with neuropathy complications?
loss of automatic and peripheral neural function
-injuries
-gangrene
-amputations
What occurs with retinopathy complications?
-failing eyesight
-blindness
-glaucoma
what is nephropathy?
-chronic kidney disease
-renal disease
-microalbuminuria
What is cerebrovascular disease?
-stroke
-ischaemic attacks
What occurs with coronary heart disease?
-angina
-hypertension
-heart failure
What is insulin?
-peptide hormone
-precursor -> proteolytic cleavage -> dipeptide and protein C
-beta cell secretes both insulin and pro-insulin
-biggest anabolic enzyme in the body
What are the levels of pro-insulin in a type 2 diabetic and how is it measured?
-high levels
-easier to measure levels of protein C to estimate insulin levels
-each have antibodies
What regulates insulin release?
- glucose, AA, FA, ketones -> stim release
- glucagon and somatostatin -> inhibit release
- a-adrenergic stim -> inhibits release
- b-adrenergic stim -> promotes release
- elevated intracellular Ca -> promotes release
What are the difference glut receptors?
-glut 1 in brain is insulin insensitive
-muscle = glut 4 = insulin sensitive
-beta cell = glut 2
What is the pathway of insulin release?
-glut 2 takes up glucose -> respiration -> ATP produced -> ATP:ADP increases -> closes K channel -> Ca channel opens -> Ca enters -> pushes out insulin
What is the difference between oral and IV glucose?
-oral glucose: more insulin secretion
-IV: less insulin secretion
-why?: oral elicits gut hormones which augment the insulin response
Where is insulin catabolized?
-by kidney
-by insulinase
What does an influx of calcium do to insulin?
-ca influx = pulsatile secretion of insulin
-activation of transcription factors for insulin
What was the first insulin from and what is it now?
-beef or pork insulin
-now usually human insulin = fewer allergies, less resistance
Which insulin form is rapid and which is prolonged?
-rapid: humalog
-prolonged: lantus
How do insulin preparations vary?
-onset of action
-time to peak
-duration
-route of admin
What are the different ways insulin can be administered?
-SC
-Insulin pump
-powder inhaler
-IV
he will ask to name each of the types, two of each, don’t need to know rest
What are the names of the Rapid-acting analogs? Clear or cloudy?
-Humalog (lispro)
-Novorapid (aspart)
-both are clear
What are the names of the regular/fast-acting analogs? Clear or cloudy?
-Humulin-R
-Novolin GE toronto
-clear
What are the names of the intermediate-acting analogs? Clear or cloudy?
-Humulin N & L
-Novolin GE NPH
-cloudy
What are the names of the long-acting analogs?
-Humulin-U
-cloudy
What are the names of the extended-acting analogs?
-Lantus (glargine)
-clear
What are the names of the premixed insulin?
-Humalog Mix25
-Novolin GE 10/90
-cloudy
What does the proportions on premixed insulin mean?
-ex. Novolin GE 20/80
-% rapid or fast / % intermediate
What makes the insulin types cloudy?
-additives
-zinc analogs
-makes it long-acting
What is the structure of human insulin?
-51AA
-two chains connected by 2 disulfide bridges
What is the half-life of human insulin and what is it degraded by?
-5-10 min
-deg. by glutathione-insulin transhydrogenase (insulinase)
What is the structural difference between human, bovine, and pork insulin?
-human: 51 AA
-bovine: differs in 3 AAs from human
-pork: differs in 1 AA from human
What are the effects of rapid insulin?
-incr. GLC tranport, AA, K+ into insulin sensitive cells
What are the effects of intermediate insulin?
-stim. protein synth
-Inhibit protein breakdown
-activate glycogen synthase
-inhibit gluconeogenic enzymes
What are the effects of delayed insulin?
-incr. mRNA for lipogenic enzymes = lipogenesis
