exam 2: insulin Flashcards

1
Q

fendocrine pancreas. is 1%

islet of Langerhan cells:
A cells secrete=
B cells secrete=

D cells= (inhibitor)
F cells=

A

A cells secrete= glucagon
B cells secrete=insulin

D cells secrete= somatostatin (inhibits A and B cells)

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2
Q

majority of the islets of langerhan cells:

A

a and B cells

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3
Q

exocrine portion of pancreas is what releases _____ enzymes into the lumen of the small intestine

A

digestive

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4
Q

a and b cells go into_____ (why called endocrine)

A

into blood

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5
Q

majority of the pancreas is ____ cells that are moved into duadumen for digestion

A

acinar cells

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6
Q

insulin secretion is associated with

A

energy abundance

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7
Q

insulin is composed of two amino acid chains, connected by:

A

disulfide linkages

and a and b chains

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8
Q

when a and b chains are split in insulin, functional activity of insulin molecule is

A

lost

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9
Q

what have virtually no insulin activity

A

proinsulin and C peptide

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10
Q

formation of insulin occurs in ___ cells. it is first made as:

A

Beta cells

first made as proinsulin

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11
Q

in the golgi, proinsulin is cleaved to form

A

c peptide and insulin

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12
Q

insulin circulates entirely in

A

unbounded form

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13
Q

what is the key regulator of insulin secretion

A

glucose

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14
Q

when glucose levels ____, this stimulates insulin synthesis

A

increase (>3.9 mmol/L)

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15
Q

mechanism of insulin secretion.

  1. glucose enters cell _____ concentration gradient
  2. glucose is metabolized until it produces:
  3. when ATP ______, this _____ the SUR channel (sulfonylurea receptor channel)
  4. this causes depolarization of:
    moving it:
  5. causes Ca2+ channel to:
    exocytosis
  6. this kinda pushes the reaction onward and increases levels of cAMP
  7. exocytosis of
A
  1. down (high to low)
  2. ATP
  3. closes channels (it is a K+ gated channel gated by the presence of ATP) aka high atp=closed channel
  4. depolarization of K+ moving it away from its equlibrium
  5. Ca2+ channel opens (exocytosis)
  6. incretins
  7. exocytosis of insulin!
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16
Q

for treatment for _______, some medications close the SUR channel

A

type 2 diabetes mellitus

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17
Q

hormones produced by the digestive system that work to stimulate insulin secretion BEFORE plasma glucose is elevated.

GLP-1 and GIP

A

incretins

ozempic!!

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18
Q

normal fasting blood glucose is _______mg/100ml

A

80-90mg/100 ml

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19
Q

insulin secretion rises when blood glucose rises above

A

100 mg/100ml

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20
Q

peak insulin secretion occurs when blood glucose reaches

A

400-600 mg/100 ml

21
Q

what is an antigonist of insulin

22
Q

glucagon levels decrease as ____ levels increase

23
Q

as insulin secretion levels increase, glucose levels

until glucose levels get to

A

increase

get to 400-600

24
Q

insulin is a ________ receptor

A

tyrosine kinase-linked receptor

25
the target cells responses: ______= increased glucose uptake especially by muscle cells and adipocytes due to translocation of vesicles containing GLUT-4 to the membrane
FAST in seconds. glucose transport
26
the target cells responses: the membrane becomes more permeable to many amino acids along with potassium and phosphate ions. _______= change in enzyme activity leading to changes in metabolism
slower (10-15 minutes) -fat synthesis -protein synthesis -glycogen synthesis
27
amino acids, ketones, various nutrients, gastrointestinal peptides (GLP-1), and neurotransmitters also influence ____ secretion
insulin
28
the target cells responses: the membrane becomes more permeable to many amino acids along with potassium and phosphate ions. ____= changes in gene expression and growth
slowest (hours to days)
29
insulin promotes muscle glucose uptake and metabolism-anabolic effect via
via GLUT-4: (effects of insulin on muscle)
30
resting muscle membrane is
only slightly permeable to glucose
31
what stimulates increases of glucose transport and how?
insulin via increase in GLUT-4 in the membrane
32
when the glucose comes in, there is going to be conversion of it into glycogen (anabolic effect) which increases:
increases glycogen storage in skeletal muscle and increases protein synthesis and inhibits protein degradation (anabolic effects)
33
effect of insulin on protein metabolism and growth. promotes ________ synthesis and ______. Inhibits:
-promotes protein synthesis and storage -inhibits protein degradation
34
insulin and growth hormone interact SYNERGISTICALLY to promote
growth
35
lack of insulin causes: 1 2
protein depletion and increased plasma amino acids
36
effects of insulin on liver.insulin promotes the ____ and ___ of glucose as glycogen by the liver
insulin promotes the uptake and storage of glucose (as glycogen) by the liver
37
insulin promotes conversion of excess glucose into: and inhibits:
fatty acids inhibits production of new glucose aka gluconeogenesis
38
effect on insulin on fat metabolism. insulin promotes: 1 2
insulin promotes fat synthesis and storage
39
storage form of fatty acids are
triglycerides
40
increase glucose transport into adopocyte, increases number of TG-rich lipoproteins that enter the adipocyte (adipose tissues) which activates _______ in the capillary walls of adipose tissues leads to splitting ______ into fatty acids and absorption into adipocytes
lipoprotein lipase LPL splitting TG (triglycerides) into FA
41
how you break down triglycerides to put FA into blood: we want to block this pathway because we need to store things
hormone-sensitive lipase
42
essential effects of insulin for fat storage in adipose tissue:
-inhibits action of HSL -enhances glucose transport into adipocytes (to store)
43
(effects of insulin on Fat Metabolism) lack of insulin causes _____ and release of _____ into the blood and increases plasma cholesterol and phosphlipids
lipolysis and release of FFA
44
net effects of plasma for major target tissues of insulin:
decrease in all 1. glucose 2. FFA 3. ketoacids 4. amino acids
45
increase insulin secretion when what 3 things are increased: insulin will then let these go back down to normal levels
-blood glucose -blood FFA -blood amino acids
46
what happens for insulin secretion to be decreased
-decreased blood glucose -fasting somatostatin (inhibits insulin and glucagon)
47
other things that increase insulin secretion:
-SUR drugs (close K channel and cause depolarization -GLP-1 -GIP -PNS -insulin resistant; obesity these increase blood glucose and eventually cause insulin to decrease blood glucose levels to keep in window: -glucagon -GH -cortisol
48