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Endocrinology Pancreas 1
Endocrinology Pancreas 1
35
Science
Undergraduate 4
04/21/2009

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Term
What do A-cells secrete?
Definition
glucagon
Term
What do B-cells secrete?
Definition
insulin
Term
What do D cells secrete?
Definition
somatostatin
Term
What do PP cells secrete?
Definition
Pancreatic Peptide
Term
How are the dark staining cells of the pancreas arranged and what do they secrete?
Definition
Acini (sac like glands with ducts). enzymes for the digestive system.
Term
Insulin structure
Definition
two peptide chains. A chain with 21 AA and B chain with 30 AA. conneced via disulfide bridge.
Term
Insulin Biosynthesis
Definition
located on short arm of chromosome 11. Perproinsulin from mRNA in roughER of B cells. converts to proinsulin immediately. Golgi apparatus converts to insulin with cathrin.
Term
3 actions of insulin on global human metabolism level
Definition
1. control of cellular intake of certain substances, most prominently glucose in muscvle and adipose tissue.2. DNA replication and protein synthesis via control of amino acid uptake. 3. Modification of the activity of numerous enzymes.
Term
Actions of Insulin on cells
Definition
1. Increased glycogen synthesis 2. Increased fatty acid synthesis 3. Decreased proteinolysis 4. Decreased lipolysis 5. Decreased gluconeogenesis 6. Increased Amino Acid Uptake 7. Incrased Potassium Uptake 8. Arterial Muscle tone
Term
Control of Insulin Secretion
Definition
Secreted in response to elevated blood concentrations of glucose. also neural stimuli (sight and taste of food). incresaed blood AA and fatty acids
Term
Mechanism of Insulin Secretion
Definition
1. Glucose transported into B cell by facilitated diffusion through transporter 2. Elevated concentrations of glucose leads to membrane depolarization and influx of extracellular calcium. 3. Increased levels of glucose activates calcium-independent pathways that participate in insulin secretion.
Term
What is the regulatory action on blood glucose?
Definition
1. Glucose enters beta cells through GLUT2 2. Glucose goes into glycolysis and respiratory cycle where AT are produced by oxidation. 3. Dependent on blood glucose levels and ATP levels. K+ channels close and membrane depolarize 4. Depolarization Ca2+ enters cell 5. Ca2+ activates phospholipase C. 6.Increased Calcium releases synthesized insulin 7. regulates expression of insulin gene via CREB
Term
Insuline Effects on Liver
Definition
1. Inhibits glycogenolysis and gluconeogenesis 2. Promotes synthesis and storage and inhibits glycogen breakdown.
Term
Insulins effects on muscle
Definition
promotes protein synthesis in muscle by increasing amino acid transport
Term
Insulin effects on Adipose tissue
Definition
Fat in form of triglycerides. Induces production of lipoprotein lipase. Insulin inhibits intracellular lipolysis of stored triglycerides by inhibiting intracellular lipase.
Term
What substances can stimulate insulin release?
Definition
Amino Acids. Acetylcholine through through phospholipase C. cholecystokinin through adenylate cyclase.
Term
Autonomic Nervous System
Definition
increase in parasympathetic activity in response to food in GI tract.
Term
Sympathetic Nervous System action on Insulin
Definition
inhibits the release of insulin via a2 adrenergic agonists like norepinephrine.
Term
Hypoglycemia and Brain
Definition
reducing blood glucose to a low level will impair function of CNS. may result in a hypoglycemic coma.
Term
Etiology of Hypoglycemic Coma
Definition
Oral hypoglycemic agents (sulfonylureas, that induce insulin release). External Insulin. Ingestion of low-carbohydrate sugar substitutes.
Term
Clinical Signs and symptoms hypoglycemic coma
Definition
Dizziness, speech problems, even loss of consciousness. known as hypoglycemia.
Term
Causes of Type 2 diabetes
Definition
multifactorial, with combined influence of genetic susceptibility and influence of environmental factors: obesity, age, physical inactivity.
Term
Insulinoma (reactive hypoglycemia)
Definition
tumor of pancreas derived from beta cells retaining ability to synthesize and secrete insulin is autonomous of the normal feedback mechanisms.
Term
Metabolic Syndrome (prediabetes)
Definition
precondition. Elevated blood pressure, dyslipidemia (disturbance in blood cholesterol). Insulin resistance, dimished capacity for insulin response in tissues. Untreated can lead to morbidities, like hypertension, obesity, Type 2 diabetes, and cardiovascular disease.
Term
Polycystic Ovary Syndrome
Definition
insulin resistance is often presented with this disease.
Term
Can insulin be taken orally?
Definition
No it gets digested to amino acid components. Insulin is usually taken as subcutaneous injections.
Term
What cells produce glucagon?
Definition
A cells in the langerhans islets of the pancreas.
Term
What molecule inhibits the release of glucagon?
Definition
Glucose
Term
What is the most numerous cell type in the pancreatic islets?
Definition
A cells of the islets of Langerhans are the site of glucagon synthesis.
Term
What is the precursor molecule to glucagon?
Definition
Proglucagon is a large precursor molecule. It is cleaved from proglucagon and is packaged in secretory granules, and is released from the A cell by exocytosis and then secreted into the portal circulation.
Term
What is glucagon's action on the liver?
Definition
Glycogenolysis and gluconeogenesis
Term
What intracellular molecule is produced when glucagon binds to its receptor?
Definition
cAMP, which is produced from activation of adenylyl cyclase, which promotes and stimulates gluconeogenesis.
Term
Glucagon promotes hepatic output of ketone bodies from what precursor?
Definition
fatty acids (ketogenesis)
Term
What molecule is produced from D cells of langerhans islets?
Definition
Somatostatin, is inhibitor of release of insulin from pancreatic B cells and glucagon from A cells.
Term
Pancreatic Polypeptide production location
Definition
produced by PP cells located in islets in posterior protion of the head of the pancreas.
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