Flashcards
2b. Exercise Metabolism
Cards in this deck (28)
- 1What type of energy does ATP house and where is the most potent form?It holds chemical potential energy. The Phosphate bonds are high energy
- 2What are the 3 major bioenergetic pathways?1. Phosphocreatine
2. Anerobic Glycolysis
3. Aerobic Pathway - 3Enzymes involved in Phosphocreatine pathwayADP + Phosphocreatine --> ATP and creatine (via by creatine kinase)
ADP + ADP --> ATP +AMP (via adenylate cyclase) - 4Any carbs used during the PCr-ATP pathway?No.
Lactate levels remain low.
Oxygen intake increases - 5What pathway activated after PCr-ATP maxes out?Non-oxidative breakdown involving glycogen
- 6What is oxygen deficit?Lag in oxygen uptake at the beginning of exercise
- 7What is lactic thresholdPoint at which blood lactic acids rises systematically during incremental exercise
Appears @ 50-60% VO2 max in untrained people - 8What is the blood lactate threshold4 mmol/L
- 9Explanations for Lactate Threshold-muscle hypoxia;
-Accelerated Glycolysis (excess NADH converts pyruvate to lactic acid;
-Reduced rate of lactate removal - 10What enzyme promotes lactic acid formation? Location?LDH isozyme in fast twitch muscle fibers
- 11Main source of fuel for marathon runners?muscle/liver glucose and glycogen
- 12Main signal stimulating hepatic glycogen breakdown?Increased glucagon, decreased insulin, and Increase in hepatic EPINEPHRINE
- 13Can Lactate be reused?I can be converted back into pyruvate or utilized directly by the heart as an energy source
- 14What spawns the removal of lactate?Oxidation = 75%
Hepatic Gluconeogenesis = 25% - 15What controls lipolysis?Growth hormone spikes and the Sympathetic Nervous System
- 16Which Fiber type burns FFAs?Type I
- 17Fuel sources for intensities...Low intensity: Fats
High Intensity: Carbs - 18Why does High Intensity workouts use the fuel source that it does?Sparks an increase in GLUT4 recruitment in the muscles to increase glucose uptake
- 19How long before the oxidative pathway is activated?2 minutes of exercise
- 20Muscle FatigueInability to maintain the desired power output...decline in force and velocity of contraction
Decrease # of active cross bridges and less force produced per cross bridge - 21Central FatigueReduced excitatory input to motor control centers of the brain/spinal cord
-Altered excitability of Alpha and Gamma neurons - 22Peripheral Fatigue-Impairments in initiation and propagation of muscle action potentials
-Depletion of substrates for energy metabolism
-Accumulation of metabolic byproducts - 23High Frequency FatiguePart of Peripheral Fatigue
-Na/K pump can't keep up. Increase in extracellular K+ and intracellular Na+ - 24Recovery Time for peripheral fatigue30 min (fast)
- 25Low frequency fatigueAssociated with Peripheral Fatigue:
-Calcium release from the SR falls. There can be changes in the channel and associated proteins - 26Recovery time for low frequency fatigueHours
- 27What is the calcium used for in muscles?Cross Bridge Activation
- 28What causes the burning Phenomenon in muscles?Increase in H+ concentration...NOT always lactic acid