Musculoskeletal Flashcards
Made up of the contractile proteins actin and myosin and form mm fibers
Myofibrils
Muscle cell. Made up of myofibrils and form fasciculus
Myofiber
Made up of bundles of myofibers and make up a muscle
Fasciculus
Thin filament that myosin binds to in order to perform cross bridges.
Actin
Thick filament that has heads to form cross bridges by attaching to actin.
Myosin
Binds with calcium and causes tropomyosin to change positions. The little guy.
Troponin
Blocks myosin from binding with actin until troponin moves it out of the way. The long guy
Tropomyosin
Mm response to single stimulus
Twitch
Length detector that provides excitable stimuli to contract mm when stretched. Parallel w/ mm fiber
Mm spindle
Tension detector that helps avoid excessive force with contraction. Within tendons
GTO Golgi tendon organ
Force generated during a single maximal effort
Mm strength
Ability to make repeated contractions against a submaximal load over an extended period of time. Walking, breathing, posture.
Mm endurance
Torque=
Force x moment arm
Perpendicular distance from the line of action of the force to the axis of rotation
Lever arm
Difference between skeletal mm, cardiac mm, smooth mm
- smooth: multinucleus, unstriated
- cardiac: single nucleus, striated
- skeletal: multinucleus, striated
Contraction of mm physiological sequence
AP-ACh-mm cell-transverse tubule-SR(calcium)-Troponin moves tropomyosin
Describe slow twitch type I fibers (4) High High High Low
High mitochondria
High capillary
Low force
High efficiency
Describe fast twitch type IIx mm fibers (4)
Low mitochondria
Fastest Vmax
Least efficient
High force
Describe fast twitch type IIa fibers (2)
Intermediate fibers
Most trainable
Type I, IIa, IIx mm fiber energy systems
Type I: aerobic
Type IIx: anaerobic
Type IIa: anaerobic (largest capacity)
Training that increases mitochondrial density
Endurance
Mm fiber type vs athletic performance
- power athlete (sprinter)
- endurance athlete
- weightlifter/other
- power athlete: high fast twitch
- endurance athlete: high slow twitch
- weightlifter/other: 50% mixed
Relationship between force, velocity, and power of mm contraction
Peak power at 200-300* per sec. Force decreases w/ speeds above this.
Isometric exercise advantages 3
- 10 degree overflow
- Useful for jt ROM restriction
- Prevent atrophy
Isometric exercise disadvantages (4)
- Mostly slow twitch
- Limited functionality
- Gains specific to jt angle