Metabolic Effects of Glucagon and Insulin Flashcards Preview

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Flashcards in Metabolic Effects of Glucagon and Insulin Deck (43)
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1
Q

What four organs play a dominant role in fuel metabolism?

A
  • liver
  • adipose tissue
  • muscle
  • brain
    (don’t work in isolation but in network with each other)
2
Q

Each of the four main organs is specialized for what three things?

A
  • storage
  • use
  • generation of specific fuels
3
Q

What two hormones control the integration of energy metabolism?

A

insulin and glucagon

4
Q

What two hormones play a supporting role in integration of energy metabolism?

A

epinephrine and norepineprine

5
Q

What polypeptide hormone is produced and secreted by the beta cells of the islets of Langerhans?

A
  • insulin
6
Q

Insulin’s metabolic effects are ____.

A

anabolic

7
Q

True or False? Insulin and glucagon release is always coordinated?

A

True

8
Q

Insulin synthesis and secretion are stimulated by what three things?

A
  • glucose
  • amino acids (especially arginine)
  • gastrointestinal hormones (secretin)
9
Q

What is the most important stimulus for insulin secretion?

A

glucose

10
Q

What inhibits insulin secretion?

A
  • scarce dietary fuels
  • stress (fever or infection)
  • epinephrine (trauma or extreme exercise)
11
Q

What three tissues are the effects of insulin most prominent?

A
  • liver
  • muscles
  • adipose
12
Q

How does insulin effect the liver?

A

inhibits gluconeogenesis and increases glycogen synthesis

13
Q

How does insulin effect the muscles?

A

increased glycogen synthesis, glucose uptake by increasing the number of transporters

14
Q

How does insulin effect adipose tissue?

A

increased glucose uptake

15
Q

What does insulin do?

A

decreases blood glucose

16
Q

_____ causes a significant reduction in the release of fatty acids.

A

Insulin

17
Q

Insulin _____ triacylglycerol degradation and ______ triacylglycerol synthesis.

A

decreases, increases

18
Q

True or False? Insulin causes the uptake of glucose to be stored as glycogen in the liver and muscles or as triacylglycerol in adipose tissue.

A

True

19
Q

Insulin binds to high affinity receptors that have alpha and beta subunits. What do the alpha and bet subunits do?

A

beta subunit: hydrophobic and contains tyrosine kinase that is activated by insulin
alpha subunit: insulin binding site

20
Q

How does insulin effect membranes?

A

GLUT-4 transporters are recruited

21
Q

True or False? Some tissue do not require insulin for glucose transport?

A

True

22
Q

How does the insulin receptor regulate insulin?

A

It downregulates it by endocytosing the receptor containing the bound insulin

23
Q

How long does it take for GLUT-4 transporters to increase in skeletal muscle and adipose tissue?

A

seconds

24
Q

What polypeptide is secreted by alpha cells of the pancreatic islets of Langerhans?

A

glucagon

25
Q

Glucagon (along with epinephrine, cortisol, and growth hormone) is considered a “_______ hormone.”

A

counterregulatory

26
Q

What is the main job of glucagon?

A

it prevents hypoglycemia by initiating certain metabolic pathways

27
Q

What are the three stimuli for glucagon secretion?

A
  • low blood glucose
  • amino acids (glucagon secreted with insulin to prevent hypoglycemia)
  • epinephrine (during stress or exercise, glucagon is secreted in anticipation of increased glucose use)
28
Q

What inhibits glucagon?

A
  • increased blood glucose

- insulin

29
Q

Glucagon increases blood glucose concentration by _____ and _____.

A

initiating glycogenolysis and gluconeogenesis in the liver

30
Q

_____ causes hepatic oxidation of fatty acids.

A

Glucagon

31
Q

_____ causes increased amino acid uptake by the liver.

A

glucagon

32
Q

What is characterized by confusion, aberrant behavior and possible coma?

A

hypoglycemia

33
Q

True or False?

Hypoglycemia symptoms can be resolved within minutes of glucose ingestion.

A

True

34
Q

Why is hypoglycemia considered a medical emergency?

A

The CNS demands a constant supply of blood-borne glucose.

35
Q

What two hormones are the two most important in preventing hypoglycemia?

A

glucagon and epinephrine

36
Q

What disease includes symptoms of adrenergic and neuroglycopenia?

A

hypoglycemia

37
Q

Receptors in what area mediate release epinephrine, ACTH, and growth hormone?

A

hypothalamus

38
Q

What are the three types of hypoglycemia?

A
  • insulin-induced
  • postprandial
  • fasting
39
Q

What is insulin-induced hypoglycemia caused by?

A

diabetics who administer too much insulin

40
Q

What causes posprandial hypoglycemia?

A

exaggerated insulin release following a meal

41
Q

What is fasting hypoglycemia caused by?

A

when the liver is unable to produce adequate glucose levels during periods of fasting or by a Beta cell tumor

42
Q

True or False? Hypoglycemia can result from alcohol intoxication.

A

True

43
Q

Alcohol consumption can cause dangerous hypoglycemia in individuals who:

A
  • have exercised strenuously for a prolonged time
  • are fasting
  • take insulin for diabetes