(L9) Integration of Metabolism Flashcards
What are key molecules that connect the metabolic pathways?
L10 S10 LO1
Glucose 6-phosphate:
- glycogen metabolism
- glycolysis
- PPP
Pyruvate:
- acetyl CoA
- OAA (gluconeogenesis)
- lactate
- alanine (protein synthesis)
Acetyl CoA:
- CO2
- ketones
- FA metabolism
What tissues are capable of using all major metabolic pathways?
L10 S9 LO1
Only the liver
What are the metabolic characteristics of the liver?
L10 S14 LO2
- processes nutrients
- reacts to dietary conditions
- maintains blood nutrient concentrations
- secretes proteins used by the rest of the body
- processes toxins and waste
Uses FAs as energy source
What organ first receives newly absorbed nutrients?
L10 S16 LO2
The liver via the hepatic portal vein.
What are the metabolic characteristics of adipose?
L10 S17 LO2
Stores triglycerides in a fed state (insulin signal)
Released FAs in states of hunger and exercise (glucagon and epinephrine signals)
Uses glucose and FAs as energy source
What are the metabolic characteristics of the brain?
L10 S18 LO2
Consumes energy using 20% of body’s O2
Uses glucose and ketone bodies
What are the metabolic characteristics of the heart?
L10 S19 LO2
Uses glucose, lactate, FAs, and ketone bodies as fuel
Must have O2
Cannot store glycogen
What are the metabolic characteristics of skeletal muslce?
L10 S20 LO2
Uses FAs and ketone bodies as fuel
High amounts of glycogen store (75% of body)
What are the three mains systems that generate ATP and when are they activated?
L10 S24 LO3
ATP/phsophocreatine reserves:
-lasts seconds before expended
Anaerobic glycolysis/glycogenolysis
-starts shortly (~20secs) after activity and ends after roughly 2 minutes
Oxidative phosphorylation and FA metabolism:
-starts nearly 2 minutes after activity
Roughly how long will stored ATP last during heavy activity?
L10 S26 LO3
1-2 seconds
What happens after initial ATP reserves are expended during activity?
L10 S26 LO3
Phosphocreatine stored in muscles replenishes supplies while other methods of ATP production are activated
Why can anaerobic glycolysis no be a long term source of ATP during prolonged activity?
L10 S27 LO3
Lactate is produced and when is builds up it results in muscle fatigue
What happens to lactate produced by anaerobic glycolysis?
L10 S28 LO3
Enters the Cori cycle and is used to regenerate glucose in the liver
What is the energy charge of a cell and what level does the cell try to maintain?
L10 S30 LO3
ATP:ADP ratio
Energy charge is maintained within a range of 0.8-0.95
What is the reducing power of a cell?
How does it relate to the energy charge of a cell?
L10 S30 LO3
NADH:NAD+ ratio
It varied inversely with energy charge
What are the main SHORT term satiating signals and what do they cause?
L10 S32 LO4
Cholecystokinin (CCK)
-triggers sense of satiation in the brain
Glucagon like peptide-1:
- triggers sense of satiation in the brain
- triggers synthesis and release of insulin by pancreas
What are the main hunger signals and what do they cause?
L10 S33 LO4
Ghrelin:
- secreted by stomach
- acts on hypothalamus to stimulate sense of hunger
- increases before a meal; decrease after
What are the main LONG term satiating signals and what do they cause?
L10 S34 LO4
Leptin:
-secreted by adipose
-acts on hypothalamus to: —trigger sense of satiation
—stimulate energy expenditure
Insulin:
- secreted by pancreatic β cells
- affects wide variety of functions and cells
What is occurring in the body in a fed state?
What signals are present in the blood?
L10 S37-38 LO4
Signals:
- insulin (high)
- glucose (high)
- glucagon (low)
Liver:
- glycolysis
- glycogen synthesis
- FA/TAG synthesis
Adipose:
-FA/TAG synthesis and storage
What is occurring in the body in a fasting state?
What signals are present in the blood?
L10 S39-40 LO4
Signals:
- insulin (low)
- glucose (low)
- glucagon (high)
Liver:
- glycogenolysis
- gluconeogenesis
- FA oxidation
- ketone body formation
Adipose:
-FA oxidation and release
What is AMPK and what is its function?
L10 S45 LO4
AMP-activated protein kinase
Inactivated by high ATP levels and activated by low ATP levels
Phosphorylates numerous targets regulating function based on energy state
AMPK is active during low energy balance and stimulates processes that will increase energy balance
What are the main energy sources of RBCs, brain, adipose, liver, and muscles?
L10 S13 LO2
RBC: glucose
Brain: glucose and ketone bodies (starving)
Adipose: glucose and FAs
Liver: FAs
Muscles: glucose, FAs, and AAs
