Flashcards in Physiology of Muscle Contraction Deck (79)
Sarcomeres end to end make up...
Many myofibrils make up the...
A single motor neuron and all of the muscle fibers it supplies
A single nerve cell
A bundle of neurons
Smallest recordable contraction, a response to a single threshold stimulus large enough to create Action Potential
First phase of muscle twitch between the stimulus and initiation of muscle twitch response
Time when excitation is recurring, action potential release of Ca and up to initial binding of myosin head to actin. No tension is generated yet
Phase where power stokes occur, onset of shortening to peak of tension development
Phase where Ca is taken back into terminal cysternae, ATP comes and and causes cross bridges to let go
Does twitch duration vary with muscle fiber type?
Which muscle have a slower twitch? Which ones have a faster?
Posturals have slower twitches
Rapid response muscles have faster twitches
Way to increase tension past the muscle twitch
Graded Muscle Response
This graded muscle response that increases the rate of stimulus delivery
What occurs when there is no relaxation from temporal summation, analagous to a charlie horse
Type of temporal summation that is good for daily activity
Graded muscle response where sequentially more units are recruited as stimulus intensity increases. Results in smooth steady increase in force.
Multiple Motor Unit Summation
Are smaller or larger units recruited first?
Smaller (less fiber associated with single nerve cell)
Graded muscle response of the warm up effect, with repeated stimuli, muscle warms up and enzymes (myosin ATPase, etc) become more efficient and stronger contraction ensues
How does treppe differ from temporal summation?
Treppe has COMPLETE relaxtion between stimuli
This is the force that is generated by cross bridge formation
Force on object
Weight on object
Type of contraction same tension but changing length of muscle
Type of isotonic contraction that shortens the muscle, only type explained by Huxley's theory (sarcomere shortening)
Type of isotonic contraction where the muscle lengthens
Ex: lift heavy weight and place it down on the table. Not explained by Huxley's theory
Contraction where the muscle stays same length but force changes.
Ex: Getting up out of chair and push against wall
Type of contraction that is mechanically induced, performed at same speed with a controlled angular velocity of joint. Doesn't happen in daily life.
Typically on exercise machines
What to type of contractions are performed in daily life?
Isotonic and Isometric contraction
Larger muscle means larger force
The 4 non-contractile elements of muscle cells that are elastic
Connective tissue covering
2 proteins that are non contractile in muscle
Titin and Nebulin
Tension in a muscle that is directed at overcoming non contractile element elasticity