Lecture 26 Flashcards
What is the fuel used by muscles to contract, how long can our stores of it last? What fuel can be used by the muscles to rapidly resynthesise the main fuel?
ATP undergoes hydrolysis into ADP and inorganic phosphate to power muscle contraction, its stores can typically last for 2-4 seconds of contraction. The muscles can use the hydrolysis of creatine phosphate into creatine and inorganic phosphate to rapidly resynthesise ATP, the muscles typically stoe enough of this for 20 seconds of contraction.
What two processes can be used to metabolise ATP?
Aerobic and anaerobic metabolism.
What substance does anaerobic metabolism use to synthesise ATP? How does this tie in with aerobic metabolism?
Anaerobic metabolism utilises glucose (produced from lactic acid or converted from glycogen) to resynthesise ATP and produce pyruvic acid. Aerobic respiration uses the pyruvic acid to synthesise more ATP in the presence of oxygen.
What primary differences seperate the effectiveness of the two ATP metabolism types?
Anaerobic processes are short term and lead to fast energy production, they require no oxygen and occur through utilisation of ATP and CP stores as well as the process of glycolysis.
Aerobic processes are longer term and steady, they have slower energy production rates and require oxygen, done using the process of oxidative phosphorylation.
When we die what happens to our ATP stores? What does this lead to and why?
Our ATP stores are all used up, this means cross bridges can not be broken, leading to rigor mortis.
What are the three muscle fibre types and what seperates their functions?
Red: contains high amounts of myoglobin, leading to a red colour, a highly aerobic fibre.
White: low amounts of myoglobin, hence a whiter colour, a highly anaerobic fibre
intermediate: a middle ground fibre, can do a bit of both.
What are the myosin types used by each fibre and each ones relative speed?
Red fibre uses myosin type I and is a slow, stable fibre due to its reliance on aerobic processes.
White fibre uses myosin type IIx and is a fast fibre due to its reliance on anaerobic metabolism.
Intermediate fiber uses myosin type IIa and has an intermediate speed as it has a moderate reliance on both ATP metabolism processes.
What seperates a muscles function besides structure and location?
The muscle fibre types which make up the muscle, muscles formed from red fibre will be more slow and stable, while those formed from white fibre will be faster and last less time before fatiguing.
What muscle fiber type will be developed regardless of muscle usage?
Intermediate fibre.
What is the smallest tension a muscle can produce? What happens if these are repeated rapidly?
A twitch. If twitchs are repeated in rapid succession they will increase in tension, a process known as a treppe.
Why do treppes occur?
Ca2+ levels are not given enough time to die down, hence more cross bridges are able to form. Also the actin myosin interaction becomes more sensitive to Ca2+ and heat production by the twitch allows for more tension.
What is a tetanus? what types can it be?
A tetanus is a series of closely spaced twitches, a rapidly repeated stimuli. This causes summation of tentions.
Incomplete tetanus is when the individual twitch fluctuations can be seen, in a complete tetanus they are not visible.
A tetanus is the contractile state muscles normally reach.
What is the time relation between muscle tension and the biochemical process which causes it?
The build up and decline of tension in a muscle takes longer than the underlying biochemical process (Ca2+ cycling).
What changes do specific muscle trainings(and lack of training) lead to?
Strength training: increases the contractile filaments (bigger muscles), gives more power and improves anaerobic function.
Endurance training: increases the blood supplyto the muscle, more blood vessels, more mitochondria, more aerobic enzymes and an improved aerobic metabolism.
Disuse: leads to loss of contractile filaments (atrophy) and less power.
What is fatigue, what types does it have?
Fatigue is a sate of exhaustion produced by strenuous muscle activity.
Exists as physiological fatigue (ATP depletion, (secondart to depletion of glucose, glycogen and oxygen)) and build up of metabolic by products like inorganic phosphate and lactic acid, or as psychological fatigue, (the brain produces sensations of fatigue to stop you from using your muscles, even though the muscle is still able to contract).
