Muscles (M+) And Movements Flashcards
3 things skeletal muscle must do
1-muscles have at least 2 attachments, must cross at least 1 joint
2-to produce movement, muscles always pull and get shorter (distal moves to proximal; insertion moves to origin)
3- muscle fibers or “striations” ALWAYS POINT to their attachments and show direction of pull
Flexor
When a muscle moves central to ventral (angle decreases)
Extensor
Muscles move the dorsal side to dorsal side (angle increases)
Filaments
Smallest component of M+
Myofibrils
Filaments clustered together
Muscle fibers
Myofibrils clustered together
Fascicle
A cluster of muscle fibers
Muscle
Fascicles clustered together
Epimysium
Layer of ct around whole tissue
Perimysium
Surrounds individual fascicles within each muscle
Endomysium
Covering each muscle fiber
Sacromere
This is the “functional unit” of the muscle cell/fiber where actual contraction happens
Muscle cramps are caused by…
1-if ATP doesn’t show up
2-dehydration or electrolyte imbalance
1) latent period
A lot happens here but doesn’t show up in the graph, motor neuron stimulates SR->SR releases Ca++ -> Ca++ binds to troponin complex and opens binding sites
2)period of contraction
Cross fridge attach and power strokes follow (CONTRACTION)
3)period of relaxation
The stimulus ends -> Ca++ is pumped back into SR -> binding sites close (RELAXATION)
Treppe
If repetitive contractions follow each other, the relation phase is not complete, leaving more Ca++ in the matrix because SR can’t pump it out all the time. This results in the following contraction to be more powerful than the one before it. Eventually M+ can run out of ATP causing myosin to be locked in power stroke known as a cramp or tetanus
Isometric exercise
M+ is contracting but CANNOT move the load this type of exercise is used in rehabilitation and keep M+ “toned” when the area of movement is limited
Isotonic
M+ contracts and CAN move the load. This is the most common form of exercise
Concentric
When the M+ is shorting (for everyone-velocity relationship)
Eccentric
When the M+ is being lengthened in a controlled manner
