Physiology: Pancreatic Hormones Flashcards
(25 cards)
Pancreatic Cell Types
Alpha Cells - Glucagon
Beta Cells - Insulin
Delta Cells - Somatostatin
F Cells - Pancreatic Polypeptide
Insulin
Protein hormone
Synthesized by Beta Cells
Stored in secretory granules
Secreted by exocytosis
Insulin Synthesis and Secretion
Glycolysis: Glucose - GK - G6P - Pyruvate - high ATP, closes K channels, opens Ca channels, Ca causes vesicle to release insulin
Insulin Synthesis and Secretion from Amino Acids, Ketoacids, Fatty Acids
Cannot be burned by metabolism, converted to glucose first then to pyruvate, which converts ADP to ATP, blocking K channel, opening Ca channel, release insulin
Insulin Synthesis and Secretion from CCK and Ach
Work via protein kinase C mechanism, causing release of insulin granules
Insulin Synthesis and Secretion by Adernergic Stimuli
Works via protein kinase A mechanism
+ glucagon
- somatostatin
Insulin Secretion is Increased by:
D glucose Glucagon Prolactin GI hormones Ketoacids Vegal activity FFA B-adernergic K+ Ca2+ Sulfonylurea Drugs
Insulin Secretion is Decreased by:
Fasting Exercise
Somatostatin PGE2
A-adernergic
Insulin Action Promotes:
- Glucose uptake in muscle and adipose tissue
- Glycolysis
- Glycogen synthesis
- Protein synthesis
- Uptake of ions
Insulin Action Inhibits:
- Gluconeogenesis
- Glycogenolysis
- Lipolysis
- Ketogenesis
- Proteolysis
Fuel Turnover
Insulin prevents break down of fat, promotes storage of excess glucose as fat
insulin takes glucose and converts it to glycogen
Insulin Effects
Stimulate uptake: K, PO4, Mg
Renal tubular absorption of K, PO4, and Na
Transport amino acids, into cytoplasm
Anabolic effect on all tissue
Type 1 Diabetes Causes
Polygenic abnormalities Autoimmune destruction of B cells Viral Chemical Radiation Damage
Type 1 Diabetes Symptoms
- Hyperglycemia and glucosuria (increase glycogenolysis and glucogenesis)
- Hyperlipidemia (decreased FFA storage)
- Ketonemia and ketoacidosis (FFA oxidation - OH butyrate and acetoacetic acid, fall in pH, academia, increased ventilation, acetone on breath)
- Hypokalemia and hyponatremia -(increase urine volume and decreased renal absorption)
Type 1 Diabetes Management:
Exogenous Insulin
Type 2 Diabetes Causes
Genetic and lifestyle factors
HLA-DR4, insulin receptor substrate-1, glucagon receptor, glycogen synthase
Type 2 Diabetes Symptoms
Increased third and urination
Increased hunger; excess craving for sweets
Loss of appetite
Fatigue
Blurred vision
Slow healing sores, increased frequency of infection
Type 2 Diabetes Risk Factors
Weight: BMI >25 Increased abdominal fat storage Sedentary lifestyle Family history Race Aging Gestational Diabetes
Type 2 Diabetes Complications
Cardiovascular Disease Neuropathy Nephropathy Retinopathy, cataracts, glaucoma Foot Damages Skin and Mouth Infections Osteoporosis
Type 2 Diabetes Tests
HbA1C 126 mg/dL
Oral glucose test: normal 140 mg/dL
Type 2 Diabetes Treatments
Active lifestyle Controlled food intake Metformin-oral, Glipzid, Acarbose Insulin Therapy Bariatric Surgery
Other Types
B-Cell Genetic Defects: MODY, Mitochondria DNA Mutations Exocrine Pancreatic Defects Endorinopathies Infections Drugs
Glucagon
Single chain polypeptide
Synthesized as preglucagon, stored in vesicles
Hypoglacemia and amino acids stimulate secretion
Glucagon Functions
Acts via cell surface receptors and cAMP
Hyperglycemic - antagonizes insulin
Stimulates gluconeogensis, inhibits glycolysis
Increases fatty acid oxidation in liver, increase plasma ketoacids
Simulates lipolysis in adipose
