T/F: Pancreas functions as endocrine and exocrine gland.True False
TRUE! Exocrine : excretes digestive enzymes into duodenum via pancreatic ductEndocrine : Insulin and glucagon regulate blood glucose (Insulin also plays a role in protein and lipid metabolism and several aspects of growth and development)
What synthesizes and secretes pancreatic hormones?
Islets of Landerhans Four primary cell types 1. Alpha (A) cells : produce glucagon2. Beta (B) cells : produce insulin3. Delta (D) cells : produce somatostatin (regulates GI absorption and motility)4. F cells : produce pancreatic polypeptide
What is the primary effect of insulin?
Lower blood glucose by facilitating entry of glucose into peripheral tissues Stored in liver : Hepatic cells permeable to glucose, even w/o insulin Stored in other tissues : Most relatively impermeable to glucose and need facilitated diffusion
How does insulin effect the glucokinase system?
Stimulates it! Phosphorylates glucose and traps molecule in hepatic cell ↑ activity of enzymes promoting glycogen synthesis, inhibits those promoting glycogen breakdown
How does insulin promote storeage of protein and lipid in muscle and adipose tissue?
Protein : stimulates aa uptake, ↑ DNA/RNA activity, inhibits protein breakdownAdipose : stimulates TG synthesis, inhibits hormone sensitive lipase (which breks down stored lipids)
What is the hormonal antagonist of insulin, and what is its primary effect?
Glucagon Increases blood glucose to maintain levels and prevent hypoglycemia Produces ↑ in glycogen breakdown in liver (glycogenolysis) Stimulates ↑ in hepatic glucose production (gluconeogenesis) to sustain blood glucose levels
How does Glucagon affect the cAMP system in the liver cells?
Binds to hepatic cell membrane and stimulates activity of adenyl cyclase enzyme Transforms ATP to cAMP (this stimulates enzymes to ↑ glycogen breakdown and stimulates gluconeogenesis)
What is normal blood glucose levels? What maintains these levels? What happens if it gets too high/low?
80-90mg/100mL of blood Insulin and glucagon maintain blood glucose withing finite range Hypoglycemia : can result in coma or deathHyperglycemia : can result in neural and vascular changes
What is the primary factor affecting pancreatic hormone release?
Level of glucose in the bloodstream Blood glucose rises : insulin released from beta cellsBlood glucose falls : glucagon released from alpha cells
What is type 1 diabetes?
Unable to synthesize enough insulin Destruction of beta cells Need exogenous insulin to survive
What is diabetes mellitus and what are the types?
Insufficient insulin secretion or decrease in peripheral effects of insulin Type I : Insulin-dependent diabetes mellitus (IDDM)/ Juvenile diabetesType II : Non-insulin dependent diabetes mellitus (NIDDM)
What causes Type II diabetes?
Genetic predisposition Poor diet, obesity, lack of exercise Usually in older individuals
What is the primary problem in type II diabetes?
Decreased sensitivity of peripheral tissues to circulating insulin (insulin resistance) Target cell defect causes decreased resonse of cell to insulin Cellular response is inadequate
What is a secondary problem in type II diabetes aside from insulin resistance?
Pancreatic beta cells intact, can produce insulin Insulin is release continuously, even when fasting After meal, beta cells don't ↑ insulin release in proportion to ↑ glucose levels
What are complications of DM?
Most common : hyperglycemiaGlycosuria : ↑ glucose excretion by kidneys (kidneys can't adequately resorb glucose)Dehydration/electrolyte imbalance : osmotic force promotes fluid excretionKetoacidosis : Loss of glucose in urine causes shift towards fat and protein mobilization for energyMicroangiopathy : Abnormalities in small blood vessels leads to occlusion (can damage retina and kidneys)--->poor wound healing and ulcers!!
T/F: Exogenous insulin is used for both type I and type II diabetes.True False
TRUE: used in type 2 b/c other interventions may not be adequate to control disease
What is a type of insulin preparation?
Lispro (Humalog) Slower than endogenous insulin Preparations can be fast or slow acting; slow acting allows more sustained levels
What are ways of administering insulin?
Nasal spray (Exubera) Subcutaneous IV in emergency
T/F: Insulin is often administered orally.True False
FALSE: b/c of large polypeptide structure
What is done in intensive insulin therapy?
Self-administering 3 or more dosages/day Monitor blood glucose levels Reduces long-term complications
What are adverse effects of Insulin Therapy?
Primary problem : hypoglycemiaStrenuous activity can cause this by having insulin-like effect Avoid by decreasing insulin by 30-35% 10-15 g D-glucose restores blood glucose in early hypoglycemia
T/F: Oral antidiabetic drugs are effective for type I and type II diabetes.True False
FALSE: only type 2 (by mouth)
What do Sulfonylureas do? Examples?
Act on beta cells to stimulate release of insulin Released into hepatic portal vein to liver to inhibit glucose production Early stages of type II Glipizide (Glucotrol) Glyburide (DiaBeta)
Azathioprine
(Imuran) Type of Immunosuppressant Minimizes beta cell loss
Exenatide
(Byetta) Type of Glucagon-like Peptide 1 Released after meal Increases after meal ↑ ability of blood glucose to stimulate insulin release from beta cells
What is sometimes used to Rx acute hypoglycemia?
Glucagon
Nonpharmacologic Intervention in DM
Diet, weight loss Exercise Tissue transplants and gene therapy of pancreas
