Physiology of the endocrine pancreas Flashcards by Geno Sadaya

Which of the following cells produce insulin?

A. alpha cells
B. beta cells
C. D cells
D. F cells

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Which of the glucose transporters is present in skeletal and cardiac muscle, and adipose tissue and facilitates insulin-mediated glucose uptake?

A. GLUT 1
B. GLUT 2
C. GLUT 3
D. GLUT 4

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Primary target of insulin

A. Glucokinase 
B. Acetyl-CoA carboxylase 
C. Uncoupling proteins 
D. Fatty acid synthase 
E. GLUT-4

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What is the most important stimulus for insulin release?

a. glucose
b. glucagon
c. adrenergic stimulation
d. cholinergic stimulation

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With inactivating mutation to GLUT-2 transporter

a. patient loses consciousness and seizure
b. pancreas do not produce insulin when glucose increases after meals
c. glucose is not transported to muscles and adipose
d. fructose is not transported

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What happens after pancreatectomy?

a. hypoglycemia
b. decreased FFA
c. decreased acetoacetate
d. metabolic alkalosis

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Insulin affects the metabolism of which substances?

a. carbohydrates
b. carbohydrates and fats
c. carbohydrates and proteins
d. carbohydrates, fats and proteins

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Which of the following is true about insulin?

a. The active hormone is composed of 4 peptides
b. The secretory granules contain insulin and c-peptide in 2:1 ratio
c. insulin is released into the duct of Wirsung to reach the liver
d. The order of synthesis of the polypeptide chain is n-terminal signal peptide- b-chain- c-peptide- a chain

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Insulin receptors belong to which family of receptors?

a) Tyrosine kinase receptor
b) Steroid receptor
c) Cytokine receptor
d) G protein-coupled receptor
e) LDL receptor

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First action of secreted insulin:

a) Activate lipoprotein lipase
b) Inhibit glucagon secretion
c) Stimulate hepatic glycolysis
d) Mobilize GLUT4 into myocellular membrane
e) Inhibit appetite

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Type 1 diabetes (juvenile-onset) suspected by parents on their child because of change in appearance or behavior.

a) Sudden increase in muscle mass
b) Darkening skin
c) Increased thirst and frequency of urination
d) Puffiness around face
e) Early pubertal growth spurt

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Which is found in the pancreatic islets?

a) Insulin-secreting alpha cells
b) Glucagon-secreting beta cells
c) Gastrin-secreting delta cells
d) Pancreatic polypeptide-secreting F cells

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Which of the following steps occur in the process of insulin secretion?

a) Opening of potassium channels
b) Closure of calcium channels
c) Exocytosis of secretory granules
d) AOTA

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Increase insulin:

a) Decrease in plasma glucose
b) Decrease in amino acid
c) Decrease in ketone bodies
d) AOTA

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The following stimulate insulin secretion except

A. decrease in blood glucose
B. GI hormones
C. acetylcholine
D. Glucagon

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Hormone which decreases plasma glucose

a. insulin
b. glucagon
c. cortisol
d. epinephrine

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Biological effects of glucagon

a. stimulate gluconeogenesis
b. stimulate glycogenesis
c. stimulate glucose uptake
d. stimulate protein synthesis

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Which cells secrete insulin?

Beta cells

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Which cells secrete glucagon?

Alpha cells

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Which cells secrete somatostatin?

Delta cells

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Which pancreatic structures consists of the endocrine pancreas?

Islets of Langerhans

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Insulin is composed of 51 amino acids arranged in two polypeptide chains. T/F

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Insulin: catecholamine, peptide, steroid, iodothyronine?

Peptide

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Two inactive precursors of insulin

Preproinsulin and proinsulin

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Insulinase, the enzyme that degrades insulin, is found in which organs?

Liver and kidney

The most important glucose-sensing cell in the body

Beta cells

A particularly important amino acid stimulus for insulin synthesis and secretion

Arg

Epinephrine (stimulates/inhibits) secretion of insulin

Inhibits

The effects of insulin on glucose metabolism are most prominent of which tissues?

Liver, muscle and adipose

Insulin decreases the production of glucose by inhibiting gluconeogenesis and the breakdown of glycogen in which organ?

Liver

Insulin increases glycogen synthesis in which organs?

Liver and muscle

Insulin increases glucose uptake by increasing the number of glucose transporters in the cell membrane in which organs?

Muscle and adipose tissue

Insulin (increases/decreases) the level of circulating fatty acids

decreases

Insulin inhibits which enzymes to decrease circulating fatty acids?

Hormone-sensitive lipase in adipose tissue

Insulin (increases/decreases) transport and metabolism of glucose into adipocytes

increases

Insulin increases the synthesis of which enzyme to promote TAG synthesis?

Lipoprotein lipase

Insulin (increases/decreases) glucose uptake

increases

Insulin (increases/decreases) glycogen synthesis

increases

Insulin (increases/decreases) gluconeogenesis

decreases

Insulin (increases/decreases) lipolysis

decreases

Insulin (increases/decreases) protein synthesis

increases

Insulin (increases/decreases) fat synthesis

increases

Insulin (increases/decreases) glycogenolysis

decreases

Insulin promotes the recruitment of which glucose transporters?

GLUT-4

Insulin (increases/decreases) glucokinase

increases

Insulin (increases/decreases) phosphofructokinase

increases

Insulin (increases/decreases) pyruvate kinase

increases

Glucagon and insulin are (agonists/antagonists)

antagonists

Glucagon (increases/decreases) gluconeogenesis

increases

Glucagon (increases/decreases) glyconeogenesis

decreases

Glucagon (increases/decreases) glycogenolysis

increases

Glucagon: catecholamine, peptide, steroid, iodothyronine

Peptide

Low blood glucose stimulates secretion of (insulin/glucagon)

Glucagon

(high/low) blood glucose stimulates secretion of glucagon

Low

(high/low) blood glucose stimulates secretion of insulin

High

What is the primary stimulus for glucagon release?

Low blood glucose

Amino acids stimulate secretion of (glucagon/insulin)

both

Epinephrine is (antagonistic/agonistic) to glucagon and (antagonistic/agonistic) to insulin

Agonistic, antagonistic

Epinephrine increases (glucagon/insulin) secretion

Glucagon

Low blood glucose (stimulates/inhibits) glucagon secretion

Stimulates

High blood glucose (stimuates/inhibits) glucagon secretion

Inhibits

Insulin (stimulates/inhibits) glucagon secretion

inhibits

Insulin receptors are (GCPR, tyrosine kinase, JAK-STAT, ion channels)

Tyrosine kinase

Glucagon receptors are (GCPR, tyrosine kinase, JAK-STAT, ion channels)

GCPR

Hypoglycemia shows symptoms of confusion, aberrant behavior or coma. T/F

Blood glucose equal or below 40 ml/dl: hypoglycemia or hyperglycemia

Hypoglycemia

Anxiety, palpitation, tremor and sweating are neuroglycopenic symptoms of hypoglycemia. T/F

F They are adrenergic symptoms

The symptoms of hypoglycemia can be divided into which categories?

Adrenergic and neuroglycopenic

Adrenergic symptoms of hypoglycemia are mediated by which hormone?

Epinephrine

Adrenergic symptoms are regulated by which organ?

Hypothalamus

Confusion, headache, slurred speech, seizures, coma and death are adrenergic symptoms of hypoglycemia. T/F

F They are neuroglycopenic. The slow decline of blood glucose deprives CNS of fuel, but fails to trigger an adequate epinephrine response.

Gradual decline in blood glucose levels: adrenergic or neuroglycopenic symptoms

Neuroglycopenic

Abrupt fall of blood glucose levels: adrenergic or neuroglycopenic symptoms

Adrenergic

The four sequential peptides of human preproinsulin

N-terminal Signal peptide β-chain of insulin C-peptide α-chain of insulin

The three parts of human proinsulin

β-chain of insulin C-peptide α-chain of insulin

C-peptide can be used to discriminate between a real hypoglycemic patient and a patient with factitious disorder. T/F

A high insulin but low C peptide concentration can mean that the insulin is exogenous. T/F

T C-peptide is once part of proinsulin, and is cleaved when insulin is activated. Thus, C-peptide levels are normally expacted to be equal insulin levels

Physiology of the endocrine pancreas Flashcards

(77 cards)