Exam 1: Diabetes Flashcards
Diabetes Mellitus vs Diabetes Insipidus
Diabetes Mellitus - Disorder in blood glucose regulation
Diabetes Insipidus - Disorder in ADH regulation (regulation of water)
Exocrine VS Endocrine
Exocrine - secretion of a substance out thru a duct
Endocrine - secretion of a substance directly into bloodstream
Pancreas Tissue
- both exocrine and endocrine
- composed of two tissue type: Acini (exo) & Islet of Langerhans (endo)
Pancreas function
Exocrine - Synthesis and release of Acini
ex: Digestive enzymes (amylase, protease, lipase) and sodium bicarbonate
Endocrine - synthesis and release of hormones by specialized cells in Islets of Langerhans
ex: Regulate glucose - insulin (beta cells and amylin) / Glucagon (alpha cells) / Somatostatin (delta cells)
Pancreatic Hormones
Insulin - Beta cell - decrease blood glucose by allowing it to enter cells (uptake into cell)
Glucagon - Alpha cell - increase release of glucose from the liver into blood
Somatostatin - Delta cell - decrease gastro activity after meal - extends time in which food is absorbed so blood glucose doesn’t rise too quickly.
Maintenance of Blood Glucose: After a meal
After a meal: Blood glucose rises - insulin secreted
Glycogenesis: 2/3 of glucose stored in liver as glycogen, 1/3 used metabolic activity
Lipogenesis: when tissues are saturated with glycogen, glucose converted to fatty acids and stored as triglycerides in fat cells
Maintenance of Blood Glucose: Between Meals
Liver releases glucose to maintain blood glucose within normal limits
Glycogenolysis: glycogen broken down to release glucose
Gluconeogenesis - synthesis of glucose from amino acids, glycerol and lactic acid
Potassium uptake by cells
GIK mechanism explanation:
When insulin binds to cell - allows for glucose to enter cell, K+ enters with glucose. Therefore, with insulin secretion, more K+ enters cells
When potassium is too high, we can inject insulin to lower K+ levels in blood to REDUCE catabolism on muscles.
High potassium can cause arrhythmia
Hypoglycemia
low blood glucose (too much insulin) coma->death
Hyperglycemia
high blood glucose (too little insulin) polydipsia (thist) polyphagia (hungry) polyuria (too much urine)
Glucagon
secreted by alpha cells of pancreas (opposite of insulin) increases blood sugar.
acts primarily in liver - stimulates glycogenolysis and gluconeogenesis
Catecholamine and glucose
Epinephrine and norepinephrine: Fight or flights.
They mobilize glucose from glycogen stores during stress response
inhibit insulin
keeps blood sugar high/ Brain needs straight glucose to function
Growth Hormone and glucose
- Helps regulate/ maintain metabolic functions (from hypothalamus -> anterior pituitary)
- Antagonizes effects of insulin
- decreases cellular uptake and use of glucose (increases blood glucose) therefore stimulates more insulin secretion
- becomes cyclic process if prolonged can contribute to insulin resistance (can lead to diabetes and acromegaly/ giantism in youth)
Glucortocoid hormones
- Cortisol is main glucocorticoid (adrenal cortex)
- Regulate metabolism of glucose during stress response
- Can raise blood glucose significantly during all types of stress (physical, emotional ect)
- also released as a result of hypoglycemia
Gut Hormones (GLP 1 & GIP)
GLP 1 & GIP - mimic the action of somatostatin.
Incretin hormones - cause increase in insulin production in beta cells / messengers btwn GI tract and pancreas
GLP-1 decreases rate of digestion
GLP-1 (glucagon-like peptide-1) - release in small bowel
GIP (glucose dependent insulinotropic polypeptide) - released in jejunum
Amylin
Similar to somatostatin in mimic of actions.
Released along with insulin from beta cells
Same effects as GLP-1: Decreases glucagon ->which decreases liver glucose production
slows rate food empties stomach
Diabetes
Disorder of carbohydrates, protein and fat metabolism - “the running through of sugar”
many factors for cause
absolutely (type 1) or relative insulin deficiency
Insulin resistance, cells cannot take up insulin as well. can be exo or endo
Diabetic Comorbidities
For children and adolescents with T1D
nephropathy hypertnesion dyslipidemia celiac disease hypothyroidism
Types of diabetes
type 1 - absolute insulin deficiency
type 1.5 - LADA
type 2 - insulin sensitivity/ secretion deficiency/ inappropriate gluconeogenesis (higher genetic risk vs type 1)
GDM - gestional diabetes (within pregnancy)
Type 1 Manifestations
Hyperglycemia & Glucosuria (sugar in urine)
Three P’s: Polyuria, Polydispsia, polyphagia
Weight loss and increased appetite blurred vision fatigue paresthesia skin infections
Glucosuria
When blood glucose is high - Glomerulus not able to filter high glucose, capacity of proximal convoluted tubule is exceeded. Glucose stays in urine, this exerts osmotic pressure, pulls fluid into filtrate, urine is watered down. Results in cellular dehydration and polyuria.
Pathogenesis of Type 2
- Genetic predispositions
- Environmental factors
-Central Obesity (visceral fat)
(causes free fatty acids = decrease in insulin production, alpha and beta cells get “burnt out”)
- Increase in hepatic glucose output in pancreas (but cells not getting it)
- Increased absorption of glucose in gut (cells still not getting enough)
Manifestations of type 2
Hyperglycemia and Glucosuria
- symptoms appear insidiously (slower)
- only 2 P’s: Polyuria and Polydipsia (both occurs slowly)
- vision problems, fatigue
- Chronic skin infections
Diagnostics tests for diabetes
- Random/casual plasma glucose test (not fasting) and not informative, unless extreme
- Fasting plasma glucose (8-12hrs)
- 2hr plasama glucose - given glucose, then checking sugar after 2 hrs (below 140)
- oral glucose tolerance test, check every hour to watch blood sugar go up then down (done for 3 hrs usually on pregnant women for GD)
Diagnostic Criteria
A1C > or = 6.5%
FPG > or = 126 mg/dl
2Hr plasma glucose > or = 200mg/dl
should all be repeated for proper diagnosis
Glycosylated Hemoglobin (HgA1C)
Glycohemoglobin = blood glucose bound to hemoglobin in RBC
this measure amount bound to RBC and is directly proportional to glucose exposure over 120 lifespan of RBC
oxygen carrying ability of RBC
reflected glucose levels over 2-3 months
7% or less is target goal
Ex: A1C of 6% = 135mg/dl