Physiology 78: Insulin, Glucagon, And Diabetes Mellitus

Front 1

What do the pancreatic acini secrete?

Back 1

digestive juices

Front 2

What do the islet cells of the pancreas secrete?

Back 2

insulin, glucagon

Front 3

alpha cells of the pancreas secrete ...

Back 3

glucagon

Front 4

beta cells of the pancreatic islets secrete ...

Back 4

insulin

Front 5

What type of receptor does insulin use?

Back 5

tyrosine kinase (2 alpha, 2 beta chains)

Front 6

During most of the day, muscles use fat for energy instead of glucose. Why?

Back 6

with normal levels of insulin, glucose cant enter the cells. only fat can

Front 7

How does glucose get into cells for energy during exercise (even though there is no insulin release)?

Back 7

exercising muscle cells are more permeable to glucose

Front 8

After a meal, muscles get their energy from (fat or carbs)?

Back 8

carbs. after a meal, the high blood sugar is a stimulus for insulin release. now carbs can get into cells to be used for energy production over fats

Front 9

How does insulin lead to increased uptake/storage of glucose in hepatic cells?

Back 9

insulin inactivates liver phosphorylase = less glycogen breakdown = more glucose uptake. increase glucokinase activity = more phosphorylated glucose = more stays in the cell (P-glucose doesn't diffuse back into the blood). insulin = more glycogen synthase

Front 10

Between meals, how does the liver maintain blood glucose levels?

Back 10

by releasing glycogen as glucose due to lack of insulin

Front 11

Lack of insulin (during starvation), would stimulate the liver to do what?

Back 11

breakdown glycogen to maintain blood sugar levels

Front 12

Insulin has what effect on brain cells?

Back 12

little effect. the brain cells can make up glucose without insulin regulation. this is unique from the rest of the body that usually requires insulin to get glucose

Front 13

INsulin has what effect on gluconeogenesis?

Back 13

decreases it. insulin woks to lower blood glucose levels

Front 14

Insulin has what effect on fatty acid synthesis?

Back 14

promotes conversion of excess glucose into fatty acids

Front 15

What effect does insulin have on fat storage?

Back 15

increases fat storage since carbs are being used for energy preferentially. fats are now stored

Front 16

What effect does insulin have on lipoprotein lipase?

Back 16

increases its activity = more fat storage

Front 17

Without insulin, what happens to levels of hormone-sensitive lipase?

Back 17

increases. now without insulin, the hormone sensitive lipase increases to release fat from adipose storage so it can be used for energy

Front 18

Why does uncontrolled diabetes lead to atherosclerosis?

Back 18

patients are now using fatty acids for energy = high fatty acids in blood = more lipoproteins = more LDL = atherosclerosis

Front 19

What is diabetic keto-acidosis?

Back 19

with high fatty acid levels in the blood (since glucose is not used for energy without insulin in these diabetics), there is also high levels of acetyl co-a = high levels of acetoacetic acid = acidosis

Front 20

Insulin has what effect on protein synthesis?

Back 20

increase synthesis and storage

Front 21

With low levels of insulin, what do we expect to see in the blood? (high or low amino acids)

Back 21

high amino acids to be used for energy substrates. no insulin = no protein storage/synthesis. muscle wasting occurs to create proteins = high AA in blood

Front 22

Insulin has what type of effect with growth hormone?

Back 22

synergistic

Front 23

Glucose becomes glucose-6=phosphate by what enzyme in the cells?

Back 23

glucokinase

Front 24

How do high glucose levels lead to insulin secretion from beta cells?

Back 24

high glucose = more glucose-6-phosphate = more ATP production = less ATP sensitive K pump = more K in the cell = calcium influx through voltage change = exocytosis of insulin vesicles

Front 25

Which 2 amino acids can increase the amount of insulin released by the pancreas?

Back 25

lysine, arginine

Front 26

Why do GI digestive hormones/enzymes lead to increased insulin secretion?

Back 26

they cause an "anticipatory" release of insulin.by making the body think that a meal has occurred and that high blood sugar will follow

Front 27

Without insulin most energy comes from (fat or carbs)?

Back 27

fat. without insulin glucose can't enter the cells well

Front 28

Epinephrine has what effect on plasma glucose levels?

Back 28

increases big time, but also increase fatty acids in the blood

Front 29

Why does epinephrine cause high sugar and fatty acids in blood?

Back 29

stimulates lipolysis and glycogen breakdown/gluconeogenesis

Front 30

In a patient with high levels of epinephrine, which energy source is more greatly enhanced? (fat or carbs)

Back 30

fat

Front 31

Glucagon main function

Back 31

increase blood glucose levels (breakdown glycogen and produce glucose)

Front 32

Overdose on glucagon leads to ...

Back 32

hyperglycemia

Front 33

How does glucagon stimulate glycogenolysis?

Back 33

activates G-protein > cAMP > protein kinase A > phosphorylase B kinase > glycogen degraded into glucose -1-phosphate > glucose release

Front 34

Glucagon uses what type of receptor?

Back 34

G-protein (cAMP mechanism)

Front 35

Glucagon has what effect on fatty acid levels in the blood?

Back 35

increases them by lipase activation

Front 36

High blood glucose levels feedback to cause glucagon levels to (rise or fall)?

Back 36

fall. if the blood glucose is already high, there is no need for glucagon

Front 37

High levels of amino acids in the blood has what effect on glucagon secretion?

Back 37

increases it. glucagon works just like insulin for AA uptake

Front 38

Exercise has what effect on glucagon secretion?

Back 38

increases; nobody really knows why

Front 39

Thinking question: If there was a patient who had low levels of insulin and glucagon in their bloodwork, where might you suspect a tumor?

Back 39

delta cells of pancreas. they secrete somatostatin which inhibits both insulin and glucagon secretion

Front 40

In severe hypoglycemia, epinephrine can help by ...

Back 40

stimulating glycogenolysis form liver

Front 41

Dehydration occurs when blood glucose is (high or low)?

Back 41

high; there is now a higher osmotic pressure. more glucose lost in urine = more water lost in urine

Front 42

Type 1 diabetes is also known as ...

Back 42

insulin dependent diabetes

Front 43

Type 2 diabetes is also known as ...

Back 43

non-insulin dependent diabetes; insulin resistance diabetes

Front 44

Major cause of type 1 diabetes

Back 44

auto-immune attack or infection of pancreatic cells (beta)

Front 45

Why might we see muscle wasting in uncontrolled diabetes?

Back 45

no insulin = less AA uptake by cells = more muscle broken down to get AA to cells

Front 46

What is the major cause of type 2 diabetes?

Back 46

obesity

Front 47

How is type 2 diabetes treated?

Back 47

thiazolidineidones (increase insulin sensitivity). metformin (decrease gluconeogenesis by liver). sulfonylureas (more insulin release)

Front 48

How do sulfonylurea drugs increase insulin secretion?

Back 48

binding the ATP dependent K channel to depolarize the membrane = calcium influx through voltage channel = exocytosis of insulin vesicles

Front 49

What is insulin shock?

Back 49

high insulin = low blood glucose = brain shuts down

Front 50

A patient with an insulinoma would have high or low blood glucose levels?

Back 50

very low levels due to excess insulin taking sugar out of the blood