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84 Cards in this Set
- Front
- Back
how long is the pancreas?
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5 inches
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what % of cells produce digestive enzymes
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99%
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what cells produce hormones
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islet cells
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are the islets endocrine or exocrine
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endocrine
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what do exocrine cells surround?
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a ducts
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what are endocrine cells near?
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capillaries
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what do alpha cells secrete?
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glucagon
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what do beta cells secrete?
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insulin
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what do delta cells secrete?
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somatostatin
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what do F-cells secrete?
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pancreatic polypeptide
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how would you test for hormone levels
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radioimmuno assays
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how many islet cells are there in the pancreas?
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1 to 2 million
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what % of the islet cells are alpha cells, and what do they produce
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20% and glucagon
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what % of the islet cells are beta cells, and what do they produce?
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70% and insulin
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what % of the islet cells are delta cells and what do they produce?
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5% and somatostatin
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what is the effect of insulin on muscle?
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promotes glucose uptake and metabolism, insulin increases permeability to glucose
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is skeletal muscle more or less permeable to muscle during exercise?
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more permeable
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if there is excess glucose in a muscle fiber, what does insulin do?
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it promotes storage of glucose as glycogen
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what is the effect of insulin on the liver?
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it promotes glucose uptake, storage and use
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what does insulin do to phosphorylase in the liver?
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it inactivates it
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what effect does insulin have on glycogen synthase in the liver?
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increases its activity (need to make glycogen)
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what is the effect on glucokinase in the liver?
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increases its activity - need to phosphorylate glucose to trap it in the cell and maintain the concentration gradient
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if the liver glyogen stores are full and there is extra glucose left over what will the liver do?
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it will begin converting glucose into fatty acids and triglycerides
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as the insulin levels decrease between meals, what happens to phosphorylase?
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it increases activity and begins splitting glycogen back into glucose
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as insulin levels fall between meals what happens to glucose phosphatase?
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it is activated, it will dephosphorylate glucose so that it can leave the liver and go to other parts of the body
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what is the effect of insulin on the brain?
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none, the brain cells are always permeable to glucose irrespective of insulin
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how does insulin effect lipid metabolism?
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it promotes fat synthesis and storage
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what will glucose be converted to on its way to becoming a fatty acid?
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glucose -->pyruvate-->acetyl CoA--> fatty acid
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what carries Fatty acids from the liver to adipocytes?
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VLDL
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what is the effect of insulin on adipose capillaries?
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it activates lipoprotein lipase
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what is the function of lipoprotein lipase?
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it breaks down the triglycerides for absorption by the adipocyte
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inside of an adipocyte, what is the effect of insulin?
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it inhibits lipases to prevent fat catabolism, and induces the formation of glycerol phosphate
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what will happen if there is a lack of insulin?
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lipolysis of stored FA and release of FFA by activating hormone sensitive lipase, increased cholesterol and phospholipid production (can lead to arteriosclerosis) and excess acetoacetic acid production for synthesis of ketone bodies
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what is the effect of insulin on protein metabolism?
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stimulates AA uptake by tissues, increases protein translation from mRNA, regulates gene expression, inhibits protein catabolism, decreases gluconeogenesis, interacts synergistically with growth hormone
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what effect does a lack on insulin have on protein metabolism?
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it leads to protein degradation and increase in AA's in blood plasma
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what are the factors that stimulate insulin secretion?
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increased glucose, amino acid, fatty acid, and keto acid concentrations, glucagon, growth hormone, cortisol, GIP, potassium, vagal stimulation (acetylcholine), sulfonylurea drugs, and obesity
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what factors inhibit insulin secretion?
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decreased blood glucose, fasting, exercise, somatostatin, alpha-adrenergic agonists, diazoxide
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what effect will sympathetic stimulation have on insulin secretion?
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it will inhibit insulin's secretion
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increased epinephrine from the adrenal medulla will lead to?
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inhibition of insulin secretion
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what are the three major effects of glucagon?
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1. breakdown of liver glycogen 2. increased gluconeogenesin in the liver 3. stimulates lipolysis
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what effect does glucagon have on adenyl cyclase?
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increased it activity which leads to an increase in cAMP, which leads to the release glycogen from the liver
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what does phosphorylase A do to glycogen?
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it splits it into glu-1-P, which is dephosphorylated and released from the liver as glucose
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will secretion of glucagon lead to protein anabolism or catabolism
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catabolism, via gluconeogenesis, to maintain constant blood glucose levels
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what effect does glucagon have on lipases?
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it increases their activtiy to mobilize FA's for energy and preserve glucose
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what inhibits glucagon secretion?
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insulin, somatostatin, free fatty acids, and ketones
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what stimulates glucagon secretion?
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fasting, decreased glucose concentration, increased AA concentration (especially arginine), CCK, beta-adrenergic agonists, acetylcholine
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what factors inhibit glucagon secretion?
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insulin, somatostatin, increased FA and ketoacid concentration
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hyperglycemia will stimulate or inhibit glucagon?
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inhibit
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hypoglycemia will stimulate or inhibit insulin?
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inhibit
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hyperglycemia will stimulate or inhibit insulin?
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stimulate
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hypoglycemia will stimulate or inhibit glucagon?
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stimulate
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what are the target tissues for insulin?
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liver, adipose tissue, muscle, satiety center in the hypothalamus
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what is the target tissue for glucagon?
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the liver
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if you are looking to build muscle mass, which hormone is more important to stimulate, insulin or glucagon?
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insulin
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what is the function of somatostatin?
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to decrease motility of the stomach, duodenum, gall bladder. It also decreases secretion and absorption in the GI
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what effect does somatostatin have on glucose and insulin?
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it inhibits them
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insulin stimulates or inhibits somatostatin?
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inhibits
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glucagon stimulates or inhibits somatostatin?
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stimulates
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what causes diabtes mellitus?
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inadequate secretion of insulin or inability of tissue to respond to insulin
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what is the difference between type I and type II diabetes mellitus
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Type I is insulin dependent, Type II in non-insulin dependent
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if there is a decrease in insulin associated with diabetes mellitus where is the problem?
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the beta cells are defective (potentially due to autoimmune disorders or viral infections)
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if there is decreased insulin secretion then what problem will arise?
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there will be very high levels of glucose in the blood
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what are some clinical signs that one may have diabetes mellitus?
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glucose in urine, dehydration (due to osmotic diuresis), polyurea (intra & extracellular dehydration), unquenchable thirst, ketoacidosis, protein breakdown
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what are some secondary effects of diabetes mellitus?
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hypertension and atherosclerosis
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what is the treatment for Type I diabetes?
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insulin therapy
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what is the major issue with Type II daibetes
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decreased sensitivity to insulin
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what is the primary cause of Type II diabetes
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obesity
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does a patient with Type II have to be on insulin therapy?
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no, many can be managed by diet, caloric restrictions
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are there treaments other than insulin for type II diabetes?
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yes, thiazolidinediones and metformin to increase insulin sensitivity and sufonylurease to increase insulin secretion
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what is the function of pancreatic polypeptide?
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it inhibits somatostatin secretion, gall bladder contraction and secretion of pancreatic digestive enzymes
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what is the function of the thymus gland?
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its secretions promote proliferation and maturation of T cells
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what hormones are secreted by the thymus?
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thymosin, thymic humoral factor, thymic factor, thymopoietin
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what are eicosanoids?
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they are local hormones secreted by all body cells
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what are the two families of eicosanoids?
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leukotrienes and prostaglandins
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what do leukotrienes influence?
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WBC's and inflammation
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what do prostaglandins do?
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they alter smooth muscle contraction, glandular secretion, blood flow, platelet function, nerve transmission, metabolism, etc.
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what us the major function of prostaglandins?
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ccontrol of vascular smooth muscle activity
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what are the localized actions of PGE/F?
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act on microcirculation & adjust local blood flow in response to changing metabolic requirements of the tissue
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what is PGI
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prostacyclins
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what do prostacyclins do?
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it is a potent inhibitor of platelet aggregation - maintains vascular flow
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where are prostacyclins produced?
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by the endothelium on the blood vessel walls
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what is the role of thromboxanes?
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may play a role in Ca+ ionophore to increase Ca, Ca may in turn regulate the changes in cellular shape needed for platelet aggregation
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where are leukotrienes made?
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in leukocytes
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what is the function of leukotrienes?
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the are potent vasoconstrictors, increase vascular permeability, induce inflammation or allergic response in sites of injury or invasion by foreign agents
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