Pancreas Flashcards
the pancreas is an _____ gland that secretes a variety of digestive hormones
exocrine
the _____ function of the pancreas secretes pancreatic islets and hormones to blood
endocrine
the four hormones the pancreas secretes to the blood
insulin, glucagon, somatostatin, pancreatic polypeptide (PP)
the pancreas is a long and slender organ located _____ to the bottom half of the stomach
posterior
the ___ cells (exocrine) of the pancreas secrete digestive enzymes to GI
acinar
the ______ (exocrine) of the pancreas secrete hormones to blood
pancreatic islets
__ cells produce insulin
beta
____ cells produce glucagon
alpha
___ cells produce somatostatin
delta
___ cells produce PP
F
____ and ____ discovered insulin
frederick banting and J.J.R. Macleod
insulin is composed of ____
two peptide chains (A chain and B chain)
A chain and B chain are linked together by _____
two disulfide bonds (and an additional disulfide is formed within the A chain)
insulin is synthesized by ______ and ____ in the beta cells
ribosome and endoplasmic reticulum
insulin is packaged into membrane-bound granules by the ____ of beta cells
golgi apparatus
insulin is secreted to the neighboring capillary and then the bloodstream by _____
exocytosis
preproinsulin consists of _____
A+B+C+ signal peptide
proinsulin consists of ______
A+B+C peptide
The C peptide is removed from proinsulin producing ____
insulin (A+B+peptide)
the half-life of insulin in the circulation in humans is about ____
5 min
insulin is destroyed by proteases in the endosomes formed by the ______
endocytotic process
4 principle actions of insulin
increase usage of nutrition, increase synthesis, increase growth, decrease degradation
for carbohydrate metabolism, insulin stimulates ____, _____, and _____
glycolysis, glycogen synthesis, and glucose uptake in muscle and adipose tissue
for fat metabolism, insulin stimulates _____
lipogenesis
for protein metabolism, insulin stimulates _____
protein synthesis
for carbohydrate metabolism, insulin stops _____ and _____
gluconeogenesis, glycogenolysis
for fat metabolism, insulin stops _____ and ____
lipolysis, ketogenesis
for protein metabolism, insulin stops ____
proteolysis
within seconds, insulin increases transport of ______ into insulin-sensitive cells
glucose, amino acids, K+
within minutes, insulin stimulates protein ____
synthesis
within minutes, insulin inhibits protein ____
degradation
within minutes, insulin activates _______ enzymes and ______
glycolytic enzymes and glycogen synthase
within minutes, insulin inhibits _____ and ____ enzymes
phosphorylase and gluconeogenic enzymes
insulin receptors have two __ and two __ subunits
alpha, beta
the alpha subunits bind insulin and are _____
extracellular
the beta subunits span the ___
membrane
the intracellular portions of the beta subunits have _____ activity
tyrosine kinase
insulin receptors have ___ effects
biologic