Integration Of Metab. Test 2 Flashcards
What energy does liver prefer?
Beta oxidation of fatty acids
How does adipose use its energy?
Synthesizes ands stores TAGs signaled from insulin it uses fatty acids from chylomicrons and VLDL to make TAGs and uses glucose from blood to make TAGs. It degrade TAG’s and releases fatty acids and glycerol signaled by glucagon and epi.
Describe the brains use of energy.
Highly dependent on blood glucose. Uses 20% of the total oxygen consumed by us. Astrocytes DO contain some glycogen and can break down to glucose for brains use and they also release lactate from doing glycolysis. The lactate can be picked up and converted back into pyruvate.
During starvation the brain switches to ketone bodies to protect the protein and aa pool from being used as energy.
When BG levels in the brain fall what begins to happen?
When glucose falls below normal range you start sweating trembling due to release of glucagon epi and cortisol. If it falls extremely low lethargy convulsions and coma can occur, if prolonged and continues dropping permanent brain damage and death can occur.
What glut do neurons use?
GLUT 3 with very high affinity for glucose
Neurons are mainly ___ while astrocytes are mainly ___
Oxidative and glycolysis
Describe the hearts use of energy.
Cardiac mm is only aerobic! Complete oxidation of glucose through TCA and OxPhos and beta oxidation of fatty acids are major source of fuel.
The heart uses ketone bodies as well and also branched chain aa.
NO glycogen reserves and lack of oxygen leads to tissue death.
Describe skeletal mm use of energy.
Rich in glycogen it contains 75% of the stores. Glycogen broken down to G6P for glycolysis. LACKS glucose 6 phosphatase so mm retains glucose and also uses fatty acids and ketone bodies
What is the ATP/PC system?
Serves need for first few seconds, immediate need of energy. Sprinting! Energy is given at quick rate but doesn’t last long. Unsustainable form of energy.
Phosphagen is regeneration of ATP by phospho creatine by phosphocreatine kinase using ADP.
Anaerobic glycolysis?
Generation of ATP by glycolysis and glycogenolysis. It has moderate speed of release and moderate amount of energy produced.
Further intense activity lasts about 30 seconds . Formation of lactate occurs causing decrease in power and mm fatigue.
GLycogen to G6P to pyr to lactate and then cori cycle picks up lactate to return to glucose.
Oxidative phosphorylation?
Production of energy from oxidizing NADH and FADH2 to produce ATP via ATP synthase.
What happens in liver in fed state?
Glycolysis glycogenesis and TG synthesis
In fasting state what occurs in liver?
Glycogenolysis Gluconeogenesis and fatty acid oxidation also ketone formation
What happens in liver in starvation?
Decrease glucose and insulin increase glucagon.
TAGs are broken to give glycerol (gluconeogenesis)and FA (fuel for mm), proteins break for gluconeogenesis, ketone bodies being made from FA from TAG break down and brain switches to ketone bodies.
What are the three junction points
- Glucose 6 Phosphate: used in gluconeogenesis to make glucose via Fru-1,6-Bisphosphatase, Glycogenesis to make glycogen via GS, Glycolysis for pyruvate via PFK-1, PPP to make Ribose 5 Phosphate via G6PDH.
- Pyruvate: made from glycolysis can be converted into Acetyl CoA via Pyruvate DH in TCA cycle, Also Lactate via lactate DH in exercising muscle. Pyruvate can go to Alanine through ALT in a transamination. Also Pyruvate can go to OAA via Pyruvate Carboxylase to enter TCA.
- Acetyl CoA can go into TCA producing CO2. Fatty acids are used to make TAG’s, Finally Ketone Bodies are synthesized from this in the liver.
