Oxygen transport and the role of myoglobin Flashcards
What is myoglobin?
- An oxygen-binding protein (like haemoglobin
- in skeletal muscle cells
- that attract O2 from the bloodstream into the muscle
- specifically to the mitochondria for aerobic energy production
- aids the delivery of oxygen to the mitochondria
How does oxygen get released to cells?
- Oxygen from pulmonary alveolus bind to hemoglobin
- hemoglobin in the blood carries oxygen from the lungs to rest of tissues
- red blood cells carries of co2 back from the tissues to the lungs
How does oxygen get to the muscles?
- Transported on haemoglobin in blood
- to capillary beds of muscles
- o2 released and diffuses into the muscle cells
Diffusion
Particles move from a region of high concentration to a region of low concentration
What is the main function of myoglobin?
aid the delivery (diffusion) of oxygen from cell membrane to the mitochondria where it is consumed
What does myoglobin do within muscle cells?
Acts as a store for oxygen
When is the oxygen bound to myoglobin released?
When oxygen diffusion from the blood is too low to meet demands
When does myoglobin stores get reduced more than normal?
- more during intermittent rather than continuous exercise
EPOC
Excess post-exercise oxygen consumption
When does the oxygen released from myoglobin get replaced?
- when the supply of o2 to muscle exceeds demand
- during recovery after exercise
- first part of epoc (excess post-exercise oxygen consumption
How does aerobic training increase oxygen utilisation in exercise?
- enhances the body’s ability to attract oxygen into the muscle cells to then use it to produce ATP for muscle contraction
How is oxygen utilisation increased?
- Increased size and number of mitochondria- the sites of ATP synthesis and where glycogen and triglyceride stores are oxidised
***The greater the number and size of mitochondria located within the muscle, the greater the oxidization of fuels to produce ATP aerobically
- Increased myoglobin stores
- aerobic training significantly increases the myoglobin content in the muscle
- increases its ability to extract oxygen and deliver to the mitochondria for energy production
Effects of aerobic training on muscle tissue
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What factors impacts the interplay between the 3 energy systems?
- intensity of the activity
- duration of physical activity
- aerobic fitness of the individual involved
How does aerobic fitness influence which energy system is predominant and the overall % contribution of each?
- as aerobic fitness increases, the body can better activate the aerobic system due to increased efficiency of o2 delivery
- more enzymes and molecules produced for aerobic respiration
Relativity of aerobic fitness and whether it is the dominant source of ATP.
The higher the aerobic fitness of an athlete, the earlier that the aerobic system will be the dominant source of ATP production
How does higher aerobic fitness of an athlete impact their use of other energy systems?
- higher aerobic fitness= the earlier the aerobic system will be the dominant source of ATP production
- means that the athlete will rely less on their LA system as they can work aerobically at a higher intensity for longer and recover quicker between successive bouts using the ATP-CP system
How can metabolic adaptation occur through the manipulation of diet?
- diet high in fats and low in carbs (traditionally high carbs/ low fat) = significantly higher rates of fat oxidation during submaximal exercise
- ## greater capacity to oxidize fats at a higher exercise intensity
- athlete who consumes a diet high in carbs and low in fats will adapt to metabolism carbs more readily during submaximal exercise
Predominant energy system v.s. intensity of sport v.s. duration (photos
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