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Flashcards in Section 6 Whole Body Metabolism Deck (123):
1

Smallest store of fuel:

carbohydrates

2

Largest store of fuel:

fats

3

In which state, fed or fasted, does glucagon dominate?

fasted

4

3 processes upregulated in the fasted state, when glucagon dominates:

Glycogenolysis, Gluconeogenesis, Ketogenesis

5

What 4 processes are up regulated when insulin dominates in the fed state?

glucose oxidation, glycogen synthesis, fat synthesis, proteins synthesis

6

What cells secrete glucagon?

alpha cells

7

What cells secrete SS?

D cells

8

What cells secrete insulin?

beta cells (insulin is a super hormone)

9

alpha, beta and D cells are all part of the endocrine/exocrine system.

endocrine

10

True or False? Decreased plasma glucose will up regulate beta cells of the pancreas.

F. down regulate

11

What pancreatic cells will upregulate the production of glucose?

alpha cells

12

What will up regulate the alpha cells of the pancreas?

decreased plasma glucose

13

What will down regulate the alpha cells of the pancreas?

increased plasma glucose

14

Prolonged ___ leads to the production of ketones.

hypoglycemia

15

Name 4 compounds that travel from the muscle to the adipose tissue:

lactate, pyruvate, amino acids, fatty acids

16

Structure of insulin receptor:

2 alpha chains 2 beta chains, all chains with N terminals facing outside of cell

17

Which domain of the insulin receptor is in the cell?

tyrosine kinase domain

18

Unique feature of the ligand binding domain:

cysteine rich domain closer to the N terminal side

19

How are the alpha and beta chains of the insulin receptor linked?

disulfide bonds

20

Insulin receptor substrates (IRS) phosphorylation of enzymes leads to:

glucose transport, protein synthesis, fat synthesis, glucose synthesis, and growth and gene expression

21

Insulin receptors are aka:

IGF-1 receptors

22

Which channels are open and which are closed during insulin secretion?

open: glucose and Ca++ both in, closed: ATP + K+ channel

23

Which glucose receptors is involved in insulin secretion?

GLUT2

24

What negatively feeds back to the beta cells of the pancreas?

decreased plasma glucose

25

Counter regulatory hormones:

glucagon, cortisol, epinephrine, norepinephrine, human growth hormone

26

Which is the largest energy store in grams?

carbohydrates, then fat, then proteins

27

location of carbohydrate storage:

liver, ECF

28

Location of protein storage:

muscle

29

Locatin of fat storage:

fat, liver

30

Which takes up a larger percentage of total body weight,

fat, then proteins, then carbohydrates

31

Largest to smallest turnover of daily energy stores:

carbohydrates, proteins, fat

32

energy storage for the brain:

there is none

33

Is the brain insulin dependent or independent?

independent

34

What will muscles use when glucose levels are low?

free fatty acids and ketones

35

8 issues with whole body metabolism:

constant demand, episodic refueling, changing demand, larger consumption of carbs than available in stores on a daily basis, fats not freely soluble in water, carbons from fats can't be converted to glucose, oxygen is required to get energy from fats, brains has minuscule stores and can not metabolize fats for fuel

36

Mechanism of action of glucagon is via:

cAMP

37

Function force glucagon:

mobilization of fuel: increase glycogenolysis, increase gluconeogenesis, increases lipolysis and ketogenesis

38

An increase in glycogenolysis leads to:

glycogen synthase inhibition and phosphorylase activation

39

What hormones inhibit glucagon secretion?

insulin and somatostatin

40

Fuels that inhibit glucagon secretion:

glucose, ketones, and free fatty acids

41

hormones that stimulate glucagon secretion:

epinephrine, norepinephrine, gut hormones (VIP, CCK), acetylcholine

42

Fuels that stimulate glucagon secretion:

amino acids

43

How many amino acids is the alpha cell made of?

29

44

How many amino acids is the alpha-chain of insulin made of?

21

45

How many amino acids is the beta-chain of insulin made of?

30

46

How many peptide chains make up insulin?

2

47

Main targets of insulin:

liver, muscle, and fat (in terms of fuel homeostasis)

48

Mechanism of action of insulin:

via tyrosine kinase receptor

49

Functions of insulin:

storage of fuels

50

Functions of adipocytes:

stimulaton of glucose uptake, storage, and glycolysis (alpha-glycerol-P), stimulate free fatty acids biosynthesis, inhibition of hormones sensitive lipase

51

Functions of muscle:

stimulate glucose and amino acid uptake, storage of glucose, glycolysis and protein synthesis

52

Functions of liver:

inhibits glycogenolysis, promotes glycolysis over glucogenesis, promotes formation of triglycerides

53

Fuels that stimulate insulin secretion:

glucose, amino acids, and free fatty acids

54

Hormones that stimulate insulin secretion:

acetylcholine, GI hormones (GIP), glucagon

55

Indirect actions of insulin secretion via effects on glucose levels:

growth hormone and cortisol

56

hormones that inhibit insulin secretion:

somatostatin, epinephrine, norepinephrine (alpha-2 receptors)

57

What cells release somatostatin?

delta cells

58

functions of somatostatin:

inhibits insulin, glucagon, growth hormone and TSH secretion (hypothalamic inhibitory hormone)

59

Role of epinephrine and norepinephrine on adipocytes in fuel homeostasis:

increase hormone sensitive lipase (hydrolysis of fats to glycerol and FFA's)

60

Role of epinephrine and norepinephrine on muscle in fuel homeostasis:

increase glycogenolysis and glycolysis (calorigenic)

61

Roles of epinephrine and norepinephrine on liver in fuel homeostasis:

increase cAMP (same action as glucagon)

62

Action of growth hormone on adipocyes:

decrease formation of alpha-glycerol-P and increase sensitivity to epinephrine/ norepinephrine (these break down glucose and glycogen)

63

Action of growth hormone on body:

decrease sensitivity to insulin

64

Functions of cortisol:

decrease sensitivity to insulin, required to mobilize protein, permissive action on adipocytes

65

Function of thyroxine:

regulates metabolic rate

66

Which Type of diabetes in juvenile onset?

Type 1, insulin dependent

67

True or False? Type 2 diabetes is insuin dependent.

F. non-insulin dependent

68

True or False? Some tissues can only metabolize glucose.

T

69

What, besides glucose can muscle metabolize?

free fatty acids and ketones, right?

70

True or False? Carb are water soluble.

T

71

glucose in our body at one time

20g (about 500 g needed for one day)

72

What is the problem with transporting fats?

lipid soluble

73

What is required for gluconeogenesis?

glycerol + amino acids

74

True or False? The largest store is what we need the most of.

F. Smallest

75

True or False? Brain is insulin dependent.

F

76

True or False? Muscle is insulin dependent

T

77

huge anabolic hormone:

insulin

78

Goal of insulin:

drive glucose into periphery

79

Primary store of large chain carbohydrates.

liver

80

Glycerol + amino acids =

feed into reverse glycolysis, de novo glucose synthesis

81

Low carbohydrates diet (high fat, low carbohydrates):

First week of weight loss, rapid loss, water loss due to metabolism of glycogen stores (glycogenolysis)

82

ketogenesis uses this process:

Beta oxidation

83

How long to u regulation enzymes in process to use ketone bodies to derive energy?

one week

84

NO carbs at all, ketones develop, leads to:

ketoacidosis, pH drops (almond breath)

85

How to control seizure activity in children?

low carbohydrates, high protein diet to put them in ketosis (decreased pH), decreases action potentials

86

What type of mode is insulin in?

anabolic modes

87

What type of hormone is glucagon?

ketogenic hormone

88

True or False? Muscle has a glycogen store.

T. does not contribute much, different time constant

89

Glycogen break down is done via this enzyme:

glycogen phosphate

90

Beta cells make up what % of the islet of Langerhans

about 60%

91

inner core of islet:

beta cells, 25% are alpha that are secreting glucagon, delta cell (somatostatin) about 10%

92

Functions of somatostatin :

universal inhibitor, (gut, gastric secretion, neurotransmitter, glucagon and insulin secretion inhibition

93

Why does somatostatin inhibit BOTH insulin and glucagon?

Fast time constant, lengthens the duration of effect

94

What type of feedback systems is used to control glucose release?

negative feedback

95

Primary target organ of glucagon:

liver

96

What process is targeted in the liver in the decreased plasma glucose state:

glycogenolysis

97

Gluconeogenesis uses what compounds?

glycerol, glucogenic amino acids, pyruvate, and lactate

98

No insulin:

no anabolic affect, shift toward catabolism

99

Precurso to insulin

pro-insulin molecule

100

Where is insulin stored?

granules in beta cells

101

How is insulin released?

insulin + c peptide in 1:1 ration

102

When can you use the fact that insulin + c peptide is released in a 1:1 ratio?

Type I or Type II, can not always distinguish between endogenous insulin vs. exogenous. Test for C-peptide. You know which it based on ratio

103

Unique aspect of insulin receptor structure:

receptors and kinase activity all in one (receptors and signal transduction process in one)

104

Kinases act on:

insulin receptor substrates

105

Net effect on target tissue of insulin:

activate, PDGF, EGF, all growth factors are one half of the insulin receptor (1 alpha, or 1 beta, etc.)

106

What do you do with insulin?

increase glucose up take and transport

107

How is glucose transport up regulated

at the levels that is already in the membranes

108

What is the back up store of transporters?

submembrane pool not yet incorporated into membranes, can't transport glucose

109

How is the beta cell being controlled?

glucose in blood increases, glucose crosses transporter, glucose need to be metabolized to provide signal so cell secretes insulin, the metabolic process (deg of glucose) provides energy to depolarize cell, oxidize to produce ATP, under resting conditions a channel opens to maintiain the cell in the hyperpolarized state. Lose K out of the cell, increase the membrane difference. ATP present, close K channel, depolarize the cell, Volatge activated Calcium channels up, calcium comes in, starts activating, and eventually allow pool of protein-insulin and insulin to be processed. Proteases activated to convert the insulin

110

Secretion of insulin is __ dependent.

Calcium dependent process

111

Why does the Ca channel need to be depolarized?

because the channel has a higher threshold than the AATP channel (?)

112

What is used in the body in lipogenesis?

Free fatty acids and glycerol

113

True or False? Insulin inhibits glycogen synthase.

F. stimulates

114

True or False? Glucagon has strong effects on muscle.

F.

115

HSL:

hormone sensitive lipase, breaks down triglycerides, when were are trying to build fat stores we inhibit this with insulin

116

Affect of glucagon on HSL:

stimulates

117

4 hormones that try and counter the actions of insulin:

glucagon, cortisol, epinephrine, norepinephrine, human growth hormone (all try to elevate glucose) (counter -regulatory hormones to insulin)

118

First line of defense against low glucose levels in the blood:

glucagon

119

How many hormones do we have that prevent glucose levels from getting too low?

4

120

Cortisol is categorized as a:

glucocortocoid (adrenal cortico hormone)

121

epinephrine is released from here to increase glucose levels:

adrenal medulla

122

What cells release glucagon

alpha cells, islet cells of the pancreas, total circulatory to the liver first

123

What happens after glucose leaves the liver?

lipolytic effects of glucagon at the adipose tissue