Section 6 Whole Body Metabolism Flashcards
Smallest store of fuel:
carbohydrates
Largest store of fuel:
fats
In which state, fed or fasted, does glucagon dominate?
fasted
3 processes upregulated in the fasted state, when glucagon dominates:
Glycogenolysis, Gluconeogenesis, Ketogenesis
What 4 processes are up regulated when insulin dominates in the fed state?
glucose oxidation, glycogen synthesis, fat synthesis, proteins synthesis
What cells secrete glucagon?
alpha cells
What cells secrete SS?
D cells
What cells secrete insulin?
beta cells (insulin is a super hormone)
alpha, beta and D cells are all part of the endocrine/exocrine system.
endocrine
True or False? Decreased plasma glucose will up regulate beta cells of the pancreas.
F. down regulate
What pancreatic cells will upregulate the production of glucose?
alpha cells
What will up regulate the alpha cells of the pancreas?
decreased plasma glucose
What will down regulate the alpha cells of the pancreas?
increased plasma glucose
Prolonged ___ leads to the production of ketones.
hypoglycemia
Name 4 compounds that travel from the muscle to the adipose tissue:
lactate, pyruvate, amino acids, fatty acids
Structure of insulin receptor:
2 alpha chains 2 beta chains, all chains with N terminals facing outside of cell
Which domain of the insulin receptor is in the cell?
tyrosine kinase domain
Unique feature of the ligand binding domain:
cysteine rich domain closer to the N terminal side
How are the alpha and beta chains of the insulin receptor linked?
disulfide bonds
Insulin receptor substrates (IRS) phosphorylation of enzymes leads to:
glucose transport, protein synthesis, fat synthesis, glucose synthesis, and growth and gene expression
Insulin receptors are aka:
IGF-1 receptors
Which channels are open and which are closed during insulin secretion?
open: glucose and Ca++ both in, closed: ATP + K+ channel
Which glucose receptors is involved in insulin secretion?
GLUT2
What negatively feeds back to the beta cells of the pancreas?
decreased plasma glucose
Counter regulatory hormones:
glucagon, cortisol, epinephrine, norepinephrine, human growth hormone
Which is the largest energy store in grams?
carbohydrates, then fat, then proteins
location of carbohydrate storage:
liver, ECF
Location of protein storage:
muscle
Locatin of fat storage:
fat, liver
Which takes up a larger percentage of total body weight,
fat, then proteins, then carbohydrates
Largest to smallest turnover of daily energy stores:
carbohydrates, proteins, fat
energy storage for the brain:
there is none
Is the brain insulin dependent or independent?
independent
What will muscles use when glucose levels are low?
free fatty acids and ketones
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
Mechanism of action of glucagon is via:
cAMP
Function force glucagon:
mobilization of fuel: increase glycogenolysis, increase gluconeogenesis, increases lipolysis and ketogenesis
An increase in glycogenolysis leads to:
glycogen synthase inhibition and phosphorylase activation
What hormones inhibit glucagon secretion?
insulin and somatostatin
Fuels that inhibit glucagon secretion:
glucose, ketones, and free fatty acids
hormones that stimulate glucagon secretion:
epinephrine, norepinephrine, gut hormones (VIP, CCK), acetylcholine
Fuels that stimulate glucagon secretion:
amino acids
How many amino acids is the alpha cell made of?
29
How many amino acids is the alpha-chain of insulin made of?
21
How many amino acids is the beta-chain of insulin made of?
30
How many peptide chains make up insulin?
2
Main targets of insulin:
liver, muscle, and fat (in terms of fuel homeostasis)
Mechanism of action of insulin:
via tyrosine kinase receptor
Functions of insulin:
storage of fuels