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DEN 7101F - Human Structure and Function > Exam 2 11/8 Howard > Flashcards

Exam 2 11/8 Howard Flashcards

1
Q

What bodily system:
- Regulates function of every cell, tissue, organ
- Maintains status quo in face of alterations from environment
- “senses” disturbances and secretes hormones

A

Endocrine system

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2
Q

What is the average energy expenditure for a sedentary adult?

A

2300 kcal/day

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3
Q

What is basal metabolic rate (BMR)?

A

the amount of energy expended to survive (~ 60-70% of total energy)

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4
Q

Fidgeting uses how much of our total energy expenditure?

A

20%

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5
Q

Diet-induced thermogenesis and nonshivering thermogenesis use how much of our total energy expenditure?

A

5-15%

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6
Q

When is the absorptive phase of metabolism?

A

2-3 hours to digest meal

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7
Q

When is the postabsorptive state?

A

between meals, energy stores must be mobilized

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8
Q

When is the fasting state?

A

Overnight, starvation

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9
Q

What are the metabolic phases?

A
  • absorptive
  • postabsorptive
  • fasting
  • strenuous exercise or physical labor
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10
Q

What enzyme catalyzes the reversible reaction between ATP and ADP?

A

Adenylate kinase

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11
Q

Kinetic controls over catabolic pathways ensure that the [ATP]/([ADP][Pi]) ratio stays very __________

A

high (more ATP than ADP)

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12
Q

How much ATP would you need to consume daily if you had to “eat” it?

A

100 lbs

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13
Q

What is AMPK?

A

AMP-activated protein kinase

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14
Q

When ATP is ______, AMPK is inactive

A

high

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15
Q

When ATP is ______, AMPK is allosterically activated

A

low

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16
Q

What is inhibited when AMPK is activated?

A

Anabolic metabolism - fatty acid synthesis, protein synthesis

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17
Q

What is stimulated when AMPK is activated?

A

catabolic metabolism - fatty acid oxidation, glucose uptake

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18
Q

Energy content of carbs

A

4 kcal/g

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19
Q

Energy content of proteins

A

4 kcal/g

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20
Q

Energy content of fat

A

9 kcal/g

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21
Q

Energy content of alcohol

A

7 kcal/g

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22
Q

analysis of __________________ can estimate the energy
requirements for different levels of exercise and evaluate food requirements for
maintaining healthy body mass

A

Respiratory gasses

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23
Q

Where all can ATP come from?

A
  • glucose
  • amino acids
  • FFAs from adipose
  • ketone bodies from the liver
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24
Q

What is the normal range of blood glucose

A

72-108 mg/100mL

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25
Q

What problems can arise from having low blood sugar?

A
  • neurological problems
  • coma
  • death
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26
Q

What problems can arise from having high blood sugar?

A
  • increased oxidative stress
  • intracellular lipids
  • lipotoxicity
  • insulin resistance
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27
Q

Can glucose diffuse across cell membrane

A

No needs transporter

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28
Q

What are transporters of glucose across the cell membrane?

A
  • sodium-glucose cotransporters (SGLTs)
  • facilitated diffusion (GLUT) transporters
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29
Q

Where are SGLTs found

A

Apical membranes of simple epithelia (intestine and proximal tubules of the kidney)

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30
Q

What GLUT receptor has a low affinity and is found in the liver and pancreatic b cells?

A

GLUT 2

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31
Q

What GLUT receptors are found in all mammalian tissues and have a high affinity?

A

GLUT1, GLUT 3

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32
Q

What is the role of the GLUT2 receptor?

A
  • pancreas: regulation of insulin
  • liver: removes excess glucose from blood
    (continuous uptake of glucose via glucokinase)
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33
Q

What is the role of the GLUT1/3 receptors?

A

Traps glucose in cell via hexokinase

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34
Q

What is the role of the GLUT4 receptor?

A
  • insulin dependent GLUT
  • central role in glucose tolerance
  • insulin promotes update of glucose by muscle and its rapid phosphorylation to G6P
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35
Q

Where are GLUT4 receptors found?

A

Skeletal muscle, adipose tissue

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36
Q

What GLUT is insulin dependent?

A

GLUT 4

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37
Q

What drives glucose uptake in the liver?

A

glucokinase

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38
Q

What transports glucose to the blood from the liver?

A

Glucose 6 phosphatase

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39
Q

How much glycogen can the liver store?

A

100g

40
Q

How much glycogen can the muscles store?

A

400g

41
Q

Why is fat storage and mobilization critical for survival?

A

Amount of caloric storage of carbs is a small fraction of the total

42
Q

____________ releases Free Fatty Acids from triglycerides carried by chylomicrons

A

Lipoprotein lipase

43
Q

The ______ is the Major Metabolic Processing Center in Vertebrates

A

liver

44
Q

Liver activity centers around

A

G6P

45
Q

glucose-6-phosphate can be:

A
  • converted to glycogen
  • released as blood glucose
  • used to generate NADPH and pentoses
  • catabolized to acetyl-CoA for fatty acid synthesis
  • energy production by oxidative phosphorylation
46
Q

What is the brains preferred substrate?

A

glucose (can use ketone bodies during starvation)

47
Q

What is the skeletal muscles (resting) preferred substrate?

A

fatty acids

48
Q

What is the skeletal muscles (resting) energy reservoir?

A

glycogen

49
Q

What is the skeletal muscles (active) preferred substrate?

A

Glucose from glycogen

50
Q

What is the skeletal muscles (active) exported energy source?

A

Lactate

51
Q

What is the heart muscles preferred substrate?

A

Fatty acids

52
Q

What is the heart muscles energy reservoir?

A

Glycogen

53
Q

What is the adipose tissue preferred substrate?

A

fatty acids

54
Q

What is the adipose tissue energy reservoir?

A

triacylglycerol

55
Q

What is the adipose tissue energy source export?

A
  • fatty acids
  • glycerol
56
Q

What is the livers preferred substrate?

A
  • amino acids
  • glucose
  • fatty acids
57
Q

What is the livers energy reservoir?

A
  • glycogen
  • triacylglycerol
58
Q

What is the livers energy source export?

A
  • fatty acids
  • glucose
  • ketone bodies
59
Q

20% of oxygen consumption is used by what organ?

A

Brain

60
Q

Does the brain have fuel reserves

A

No

61
Q

Sole fuel for the brain

A

Glucose

62
Q

What organ makes glucose during fasting periods?

A

Liver

63
Q

ketone bodies produced by liver from _________ during starvation

A

Fatty acids

64
Q

Need ____ for muscle contraction

A

ATP

65
Q

Muscles use ___% of oxygen consumption (at rest)

A

30% (from ffa, glucose, ketone bodies)

66
Q

muscle oxygen consumption (exertion)

A

90

uses:
- 2% glycogen
- 0.08% phosphocreatine
- glucose via glycolysis

67
Q

Glycolysis rapidly _______, causing muscle fatigue

A

Lowers pH

68
Q

What is the main fuel for heart muscles?

A

fatty acids (can use glucose or ketone bodies)

69
Q

________ levels dictate storage or mobilization of triglycerides

A

glucose

70
Q

Alcohol metabolism is around ___ kcal/g

A

7

71
Q

How can alcohol consumption lead to a fatty liver?

A
  • Ethanol to acetate in liver (alcohol dehydrogenase)
  • Acetate to Acetyl-CoA + NADH
  • High NADH impairs TCA, fa oxidation; promotes fa synthesis
  • Elevated liver triglycerides
  • Fatty liver and cirrhosis
72
Q

Pancreatic beta cells are associated with

A

Insulin

73
Q

pancreatic alpha cells are associated with what?

A

glucagon

74
Q

pancreatic PP cells are associated with what?

A

Pancreatic polypeptide

75
Q

pancreatic delta cells are associated with what?

A

Somatostatin

76
Q

What does insulin do?

A
  • increases absorption of glucose
  • induces storage of excess nutrients
  • suppresses mobilization
  • anabolic
77
Q

How is insulin secretion stimulated?

A
  • Glucose primary stimulus via GLUT2
  • Glucose to glucose-6-P
  • Oxidized makes ATP
  • ATP closes ATP-sensitive K+ channel
  • Depolarization opens voltage-gated Ca++ channels
  • ↑ intracellular Ca++
  • Exocytosis of granules
78
Q

What are inhibitors of insulin secretion?

A

Epinephrine, norepinephrine

79
Q

The insulin receptor is a _______ protein composed of two α- and two β-subunits

A

Tetrameric

  • tyrosine kinase
  • insulin binding (autophosphorylation)
80
Q

What are the 2 broad signaling pathways for insulin receptors?

A
  • MAPK pathway (cell growth, gene expression)
  • PI-3K pathway (synthesis of lipids/proteins, survival)
81
Q

Insulin promotes ____ reactions

A

Anabolic

82
Q

What is the purpose of glucagon?

A

↑ blood glucose via liver glucose output

*↑ glycogenolysis
*↑ gluconeogenesis
*↓ glycolysis
*↓ glycogenesis
*↓ fa synthesis

(THINK CATABOLIC)

83
Q

Primary target of glucagon

A

Liver

84
Q

Stimulus for glucacon

A

Low blood glucose

85
Q

____ opposes insulin action

A

Glucagon

86
Q

Glucagon and __________ stimulate glycogen breakdown and inhibit glycogen synthesis

A

Epinephrine (liver and muscle)

87
Q

fight or flight hormone that:
*Mobilizes large amount of glucose in liver
*Activates glycolysis in muscle cells

A

Epinephrine

88
Q

glucocorticoids are __________ hormones

A

Steroid

89
Q

Stress hormone

A

Cortisol

90
Q

Cortisol and Glucocorticoids are primarily ____________- degrade macromolecules

A

Catabolic

91
Q

What do Cortisol and Glucocorticoids do in the liver?

A
  • stimulates gluconeogenesis
  • increase glycogen synthesis
92
Q

what does fructose 2,6 bisphosphate regulate?

A

positive on phosphofructokinase 1 and negative on fructose 1,6 bisphosphatase

93
Q

High concentrations of fructose 2,6 bisphosphate stimulate what enzyme?

A

Phosphofructokinase 1 (promotes glycolysis)

94
Q

Low concentrations of fructose 2,6 bisphosphate stimulate what enzyme?

A

Fructose-1,6-bisphosphatase (promoted gluconeogenesis)

95
Q

What bifunctional enzyme activity can form Fructose-2,6 P2 from fructose-6-phosphate?

A
  • PFK 2
  • Fructose bisphosphatase 2

(controlled by phosphorylation)

96
Q

In a fed state, (insulin, high blood glucose) what enzyme is active, Phosphofructokinase 2 or Fructose bisphosphatase 2?

A

PFK 2 (promotes PFK1 activity, glycolysis to use up glucose)

97
Q

In a fasting state, (glucagon, low blood glucose) what enzyme is active, Phosphofructokinase 2 or Fructose bisphosphatase 2?

A

fructose bisphosphatase 2 (FBPase 2)

(promotes gluconeogenesis, inhibits glycolysis)

DEN 7101F - Human Structure and Function (23 decks)

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