Insulin Flashcards
The endocrine cells of the pancreas are arranged in clusters called the _______
islets of Langerhans
Islets of Langerhans compose _% to _% of the pancreatic mass.
1
2
There are approximately ______ islets of Langerhans, each containing about ____ cells.
1 million
2500
The β cells compose __% of the islet and secrete ____.
65
insulin
The α cells compose ___% of the islet and secrete ____.
20
glucagon
The delta (δ) cells compose ___% of the islet and secrete ___.
The remaining cells secrete ______ or other peptides.
10
somatostatin
pancreatic polypeptide
The central core of the islet of Langerhans contains mostly ___ cells, with α cells distributed ______.
The __ cells are interposed between α and β cells
β
around the outer rim
δ
The islets receive about ___% of the total pancreatic blood flow.
10
first hormone to be isolated from animal sources in a form that could be administered therapeutically to humans is _______
Insulin
the first hormone to have its primary and tertiary structure determined is ______?
the first hormone to have its mechanism of action elucidated is _____ , while the first hormone to be measured by radioimmunoassay is _________?
the first hormone known to be synthesized from a larger precursor (prohormone); and the first hormone to be synthesized with recombinant DNA technology.
Insulin
Insulin
Insulin
Pancreas is a Flattened organ
T/F
T
Pancreas Lies ____peritoneally & (longitudinally or transversely?) across ____ abdominal wall
retro
transversely
posterior
Pancreas is (anterior or Posterior?) to stomach, between duodenum on (left or right?) & spleen on (left or right?)
Posterior
Right
Left
Pancreas is Classified as purely endocrine
T/F
F
endocrine & endocrine
Somatostatin Inhibits secretion of insulin and stimulates secretion of glucagon
T/F
F
Inhibits insulin & glucagon
Insulin is a peptide hormone consisting of two straight chains, an A chain (___ amino acids) and a B chain (__ amino acids).
21
30
________ link the A chain to the B chain of insulin , and a ___________ is located within the A chain.
Two disulfide bridges
third disulfide bridge
The synthesis of insulin is directed by a gene on ___, chromosome a member of a superfamily of genes that encode related growth factors.
11
Stimulatory Factors of insulin secretion
___eased glucose concentration
___eased amino acid concentration
___eased fatty acid
Incr
Incr
Incr
Decreased ketoacid concentration stimulates insulin secretion
T/F
F
Hormones that stimulate insulin secretion are
______
_____
______
_____
glucagon
growth hormone
cortisol
GIP Potassium
Vagal stimulation by _____
acetylcholine
Sulfonylurea drugs e.g., ______ , _______ etc , (stimulate or inhibits) insulin secretion
tolbutamide
glyburide
Stimulates
Obesity (stimulates or Inhibits ?) insulin secretion
Stimulates
Inhibitory Factors of inulin secretion
____eased blood glucose
___ Adrenergic agonists
glucose
α
Fasting increases or inhibits insulin secretion
Inhibits
Exercise stimulates or inhibits insulin secretion???
Inhibits
Somatostatin stimulates or inhibits insulin secretion
Inhibits
Diazoxide stimulates or inhibits insulin secretion
Inhibits
Mechanisms of Insulin secretion by pancreatic cell
Transport of ____ into the ___ cell
Metabolism of ____ inside the cell occurs
ATP closes ____ channel
Depolarization cases ____ of calcium channels
Increased ___cellular calcium causes insulin secretion
glucose; beta
glucose
ATP; potassium
opening;calcium
intra
MECHANISM OF ACTION
Insulin binds with the ____ subunit
It elicits a change in the ___ subunit causing it to _______
______ is activated causing further _____ of kinases and enzymes involved in insulin action
Insulin receptor complex is then _____, meaning It is either ______ by ____, stored, or _____ to the cell membrane to be used again.
alpha
beta; autophosphorylate
Tyrosine kinase; phosphorylation
internalized; degraded by proteases
recycled
Action of Insulin
\_\_\_\_eases glucose uptake into the cells \_\_\_\_eases glycogen formation \_\_\_\_eases glycogenolysis \_\_\_eases gluconeogenesis \_\_\_\_eases protein synthesis \_\_\_\_eases fat deposition \_\_\_\_\_eases lipolysis \_\_\_\_eases K + uptake into cells
Incr
Incr
Decr
Decr
Incr
Incr
Decr
Incr
Effect on Blood level
___ease blood glucose
____eases blood f.acid
____eases blood a.acid ____eases blood ketoacid
_____eases blood [K+]
Decr
Decr
Decr
Decr
Decr
Insulin-dependent diabetes mellitus or type __ diabetes mellitus , is caused by destruction of _____, often as a result of ______ process.
I
β cells
an autoimmune
Inadequate Insulin secretion results in metabolic derangement of CHO, fat, and protein metabolism.
T/F
T
The nonreabsorbed glucose acts as an osmotic ____ in urine, producing an osmotic _____, poly___, and _____.
solute
diuresis
uria
thirst
Polyuria produces ECF volume (contraction or expansion?) and ___tension.
contraction
hypo
Lack of insulin also causes a shift of K + hyperkalemia (out or in?) of cells, resulting jn ____kalemia
Out
Hyper
Treatment of type I diabetes mellitus consists of ________ therapy.
insulin replacement
Non insulin dependent diabetes mellitus ,or type __ diabetes MELLITUS, is often associated with ____.
2
obesity
Type II diabetes mellitus is caused by _____ of _____ in target tissues and insulin _____.
down regulation
insulin receptors
resistance
In type 2 diabetes, Insulin secreted cannot ______ on ____, ____, and _____; thus, insulin is unable to produce its usual metabolic effects.
activate its receptors
muscle; liver ; adipose tissue
Treatment of type II diabetes mellitus includes
caloric ____ and weight ____
treatment with drugs e.g., _______ or ________, which _____ pancreatic insulin secretion; and treatment with ___ drugs (e.g., ____), which _____ insulin receptors on target tissues.
restriction
reduction
sulfonylurea tolbutamide or glyburide
stimulate
biguanide; metformin; upregulate
GLUCAGON
Secreted by the ____ cells.
alpha
_______“mirror’s the image” of insulin
Glucagon
insulin is the hormone of “ ________”
abundance
glucagon is the hormone of “_____.”
starvation
In contrast to insulin, which promotes storage of metabolic fuels, glucagon promotes their mobilization and utilization
T/F
T
Stimulatory factors for glucagon release
Fasting
T/F
T
Decreased glucose concentration inhibits glucagon secretion
T/F
F
Increased amino acid concentration stimulates glucagon, especially ______ and ____)
arginine and alanine
Cholecystokinin (CCK) inhibits glucagon
T/F
F
ACTIONS OF GLUCAGON
____eases glycogenolysis
____eases gluconeogenesis
____eases lipolysis
____eases ketoacid formation
Incr
Incr
Incr
Incr
Somatostatin
Pancreatic somatostatin, a polypeptide with ____ amino acids, is secreted by the ___ Langerhans cells
14
δ
Secretion of somatostatin is stimulated by the ingestion of all by 2 forms of nutrients
T/F
F
All forms
Somatostatin secretion is inhibited by ____ via an ____ paracrine mechanism.
insulin
intraislet
Pancreatic somatostatin inhibits secretion of insulin and glucagon via ___ actions on the α and β cells.
paracrine
GLUT2, a specific transporter for glucose that moves glucose from the ____ into the ___ by _____
blood
cell
facilitated diffusion
_____________ (GIP)
glucosedependent insulinotropic peptide
intravenous glucose is a more powerful stimulant for insulin secretion than oral glucose.
T/F
With reason
F
The reason for this difference is that oral glucose stimulates the secretion of glucosedependent insulinotropic peptide (GIP), a gastrointestinal hormone that has an independent stimulatory effect on insulin secretion (adding to the direct effect of glucose on the β cells). Intravenous glucose does not cause the release of GIP and thus only acts directly
Insulin increases glucose transport into target cells such as muscle and adipose by directing the insertion of glucose transporters (____) into the cell membranes
GLUT4
Which glucose transporter takes glucose from blood, into the beta cell
GLUT 2
