Flashcards in Physiology of Muscle Contraction Deck (79)
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1
Sarcomeres end to end make up...
Myofibril
2
Many myofibrils make up the...
Muscle fiber
3
A single motor neuron and all of the muscle fibers it supplies
Motor Unit
4
A single nerve cell
A bundle of neurons
Neuron
Nerve
5
Smallest recordable contraction, a response to a single threshold stimulus large enough to create Action Potential
Muscle Twitch
6
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
Latency
7
Phase where power stokes occur, onset of shortening to peak of tension development
Contraction
8
Phase where Ca is taken back into terminal cysternae, ATP comes and and causes cross bridges to let go
Relaxation
9
Does twitch duration vary with muscle fiber type?
Yes
10
Which muscle have a slower twitch? Which ones have a faster?
Posturals have slower twitches
Rapid response muscles have faster twitches
11
Way to increase tension past the muscle twitch
Graded Muscle Response
12
This graded muscle response that increases the rate of stimulus delivery
Temporal Summation
13
What occurs when there is no relaxation from temporal summation, analagous to a charlie horse
Tetany
14
Type of temporal summation that is good for daily activity
Wave Summation
15
Graded muscle response where sequentially more units are recruited as stimulus intensity increases. Results in smooth steady increase in force.
Multiple Motor Unit Summation
16
Are smaller or larger units recruited first?
Smaller (less fiber associated with single nerve cell)
17
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
Treppe
18
How does treppe differ from temporal summation?
Treppe has COMPLETE relaxtion between stimuli
19
This is the force that is generated by cross bridge formation
Force on object
Weight on object
Contraction
Tension
Load
20
Type of contraction same tension but changing length of muscle
Isotonic contraction
21
Type of isotonic contraction that shortens the muscle, only type explained by Huxley's theory (sarcomere shortening)
Concentric
22
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
Eccentric
23
Contraction where the muscle stays same length but force changes.
Ex: Getting up out of chair and push against wall
Isometric
24
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
Isokinetic
25
What to type of contractions are performed in daily life?
Isotonic and Isometric contraction
26
Larger muscle means larger force
(DUH)
27
The 4 non-contractile elements of muscle cells that are elastic
Connective tissue covering
Tendons
Organelles
Sarcolemme
28
2 proteins that are non contractile in muscle
Titin and Nebulin
29
Tension in a muscle that is directed at overcoming non contractile element elasticity
Internal
30
