Muscle Flashcards
Skeletal muscle
Responsible for voluntary movement and are usually attached to bone.
Require direct stimulation from the CNS to move otherwise they are flaccid.
Muscle
Effectors for movement in the body.
Responsible for generating force. This force either moves body parts with respect to the environment or moves substances around the body.
Smooth muscle
Control internal organs and moving stuff around the body.
Involuntary control and can contract with out CNS input in physiological saline.
Ex: GI tract, surrounding arteriols
Contraction
Generation if force.
Does not necessarily mean a shortening.
Shortening contraction
Fext<Fmuscle
Isometric contraction
The length of the muscle stays the same.
Fext=Fmuscle
Lengthening contraction
Muscle length increases but it is still creating a counteracting force.
Fext>Fmuscle
Swing phase
A) Weight starts on the left leg then right knee flexes to lift the foot off the floor. The knee flexor performs a shortening contraction.
B) For touchdown the right knee extends. Shortening contraction of knee extensor.
Stance Phase
A) Right knee extensor is still contracting (lengthening contraction).
B) Shortening construction if knee extensor to prep for swing phase.
Thick filaments
Made of myosin
The heads of the myosin are responsible for the force generation because they have biding sites on actin molecules.
Each attachment and detachment cycle costs 1 ATP
Thin filament
Actin
Sarcomere
Z-line to z-line.
Increased muscle length
Increased distance between z-lines Increased total I band length Increased H-zone length Decreased amount of A band not in H-zone Increased length of sarcomere
No change
Length of A band
Length of z-line to the end of H-zone
I-band
The part of the thin filament in which there are no thick filaments.
