Muscle 2 Flashcards
What types of processes do the muscles us energy for?
The reaction of the cross bridges -ATP is used to release rigor state and start the cycle again Maintenance of ionic equilibrium -Na+/K+ exchanger Removal of Ca 2+ after contraction -SERCA ( 2 Ca2+/ATP) Growth and energy storage -creation of glycogen, protein synthesis
In terms of exiting the cell how is a muscle cell different than a liver cell once glucose has entered it?
Glucose can’t leave a muscle cell because it lacks glucose-6-phosphatase enzyme
Phosphates system
High energy pool for short amounts of work
Ex: sprinter
Glycogen-lactic acid system
Slightly higher amounts activity for a little more time
Ex: swimmer
Aerobic respiration
Gives a lot of energy for a long amount of time
Ex: marathon runner
There are two types of muscle contractions….Name and define them.
Isometric contractions: length of muscle does not change during contraction
Isotonic contractions: load of muscle does not change during contraction but length does
-Eccentric
-Concentric
Eccentric vs Concentric contractions
Eccentric contraction: muscle lengthens due to external forces on the muscle (muscle can’t overcome workload but it can keep it from falling)
Concentric contraction: muscle tension rises to meet resistance, then does not change. ( muscle can meet or overcome workload so it shortens)
Formula for work and power
Work=force x distance
Power= work/time
=force x distance /time
=force x velocity
What is optimal length?
At this length the muscle fiber can generate the highest amount of force. It’s mediated by overlap of thick and thin filaments as well as lattice spacing
Which one is done during an isometric contraction: work or power?
Neither
In an isotonic contraction the muscle lifts a heavy load slowly, what happens to the muscles? When do the muscles experience their maximal shortening velocity?
The muscles shorten rapidly when lightly loaded and they exhibit their maximal shortening when they are not loaded
Define Twitch, incomplete tetanus and tetanus.
Twitch: sub maximal response to a single action potential
Incomplete tetanus: sub maximal response with a longer duration
Tetanus: maximal response with a long duration
In regards to action potentials, how can we alter them to change force and duration?
Firing rate of axon terminals alter the calcium concentration of the cell.
Basically change the calcium levels
What is a motor unit?
A motor unit consist of all the muscle fibers inner varied by a dingle motor neuron.
It’s the functional contractile unit
What is the size principle?
The motor units with the smallest fibers are the first recruited followed by the larger motor units
