Metabolism And Exercise Flashcards
What must metabolism be able to do during exercise?
It must ensure that excess energy demands are met, it must ensure homeostasis is not affects (mobilisation rate = utilisation rate), it must ensure there is a glucose supply for the brain and that waste products are removed efficiently.
Name three factors which alter the magnitude and nature of the response.
Type of exercise, intensity and exercise duration, physical condition.
What are the two uses for ATP during exercise?
ATP is mainly used by myosin ATPase for muscle contraction and the remainder is used to maintain ionic gradients!
What are the two pathways used to provide energy during exercise, and comment on their efficiency?
Glycolysis (inefficient) and Oxidative Phosphorylation (requires oxygen).
What is the initial energy store which is drawn upon after the use of Creatine phosphate in the muscles?
Muscle glycogen.
What is muscle glycogen broken down into during intense exercise?
It enters glycolysis and is converted to lactate.
State two substances which promote glycogenolysis during exercise.
AMP and adrenaline.
Which organ is principal for blood glucose maintenance? What two processes occur here during exercise?
Glycogenolysis, gluconeogenesis.
What are the changes to glucose uptake in muscle when it is exercising?
During exercise high AMP creates a signalling cascade and increased GLUT 4 translocation so glucose uptake can be independent of insulin.
What are the limitations of using fatty acids as an energy source during exercise?
Breakdown in adipose is slow, there is limited carrying capacity of the blood and the Carnitine shuttle only has limited space to move them into mitochondria for oxidation.
Describe what happens in the body during a 100m sprint.
Oxygen cannot be delivered to the tissues quickly enough and so this is anaerobic. After Creatine phosphate has been used up there is incomplete glucose metabolism which leads to a build up of lactate and fatigue. Blood glucose is spared for the brain.
In a middle distance or medium intensity work out, what percentage is anaerobic?
Approximately 40%
What are the three stages in a middle distance run?
Initially Creatine phosphate and muscle glycogen are used which is anaerobic. There is then an aerobic middle section where muscle glycogen is used and then the final sprint finish is anaerobic and produces lactate.
What energy stores are used during a marathon?
Muscle/liver glycogen and fatty acids.
After what time exercising do fatty acids begin to be utilised?
After approx 20-30 minutes.
