Section 6 Whole Body Metabolism Flashcards
(123 cards)
1
Q
Smallest store of fuel:
A
carbohydrates
2
Q
Largest store of fuel:
A
fats
3
Q
In which state, fed or fasted, does glucagon dominate?
A
fasted
4
Q
3 processes upregulated in the fasted state, when glucagon dominates:
A
Glycogenolysis, Gluconeogenesis, Ketogenesis
5
Q
What 4 processes are up regulated when insulin dominates in the fed state?
A
glucose oxidation, glycogen synthesis, fat synthesis, proteins synthesis
6
Q
What cells secrete glucagon?
A
alpha cells
7
Q
What cells secrete SS?
A
D cells
8
Q
What cells secrete insulin?
A
beta cells (insulin is a super hormone)
9
Q
alpha, beta and D cells are all part of the endocrine/exocrine system.
A
endocrine
10
Q
True or False? Decreased plasma glucose will up regulate beta cells of the pancreas.
A
F. down regulate
11
Q
What pancreatic cells will upregulate the production of glucose?
A
alpha cells
12
Q
What will up regulate the alpha cells of the pancreas?
A
decreased plasma glucose
13
Q
What will down regulate the alpha cells of the pancreas?
A
increased plasma glucose
14
Q
Prolonged ___ leads to the production of ketones.
A
hypoglycemia
15
Q
Name 4 compounds that travel from the muscle to the adipose tissue:
A
lactate, pyruvate, amino acids, fatty acids
16
Q
Structure of insulin receptor:
A
2 alpha chains 2 beta chains, all chains with N terminals facing outside of cell
17
Q
Which domain of the insulin receptor is in the cell?
A
tyrosine kinase domain
18
Q
Unique feature of the ligand binding domain:
A
cysteine rich domain closer to the N terminal side
19
Q
How are the alpha and beta chains of the insulin receptor linked?
A
disulfide bonds
20
Q
Insulin receptor substrates (IRS) phosphorylation of enzymes leads to:
A
glucose transport, protein synthesis, fat synthesis, glucose synthesis, and growth and gene expression
21
Q
Insulin receptors are aka:
A
IGF-1 receptors
22
Q
Which channels are open and which are closed during insulin secretion?
A
open: glucose and Ca++ both in, closed: ATP + K+ channel
23
Q
Which glucose receptors is involved in insulin secretion?
A
GLUT2
24
Q
What negatively feeds back to the beta cells of the pancreas?
A
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
