Muscular System & Types of muscles Flashcards
Muscle Fiber Types
Type I (slow-twitch), Type IIa (Intermediate), Type II (fast-twitch)
Type I
Smaller in size produces less force, slow to fatigue, higher aerobic capacity due to a large number of capillaries, mitochondria, & myoglobin for increased oxygen delivery & usage. (slow-twitch)
Type IIa
Hybrid with both fast (explosive) & (slow ) endurance capabilities.
Type II
Larger in size, produce more force, quick to fatigue, higher in anaerobic capacity, and decreased oxygen delivery due to less capillaries, mitochondria & myoglobin.
4 Behavioral Properties of Muscle
Extensibility- The ability to be stretched or lengthened
Elasticity- The ability to return to normal or resting length after being stretched
Irritability- The ability to respond to a stimulus
Ability to develop tension
Sliding filament theory
Actin filaments at each end of the sarcomere slide inward on myosin filaments, pulling the z lines toward the center of the sarcomere and thus shortening the muscle fiber causing it to contract.
Sarcomere
Made up of two types of muscle protein: Actin (thin filament) & myosin (thick filament) which slide across each other to provide muscle contraction. The arrangement of myosin & actin give muscle its striated appearance.
Muscle spindles
Proprioceptors that sense any stretching or tension within a muscle (contract)
Golgi tendon Organs
Attach to the tendons near the junction of the muscle. They are proprioceptors that detect differences in tension & when excessive tension is detected they send a signal to prevent the muscle from contracting to prevent muscle injury resulting from over contraction. (relax)
Autogenic Inhibition
The process by which neural impulses that sense tension (GTO) are greater than the impulses that cause muscles to contract (Muscle Spindles), providing an inhibitory effect to the muscle.
Reciprocal Inhibition
The simultaneous contraction of one muscle and the relaxation of its agonist to allow movement to take place.
*During bicep curl tricep relaxes
Length-Tension Relationship
the resting length of a muscle and the tension the muscle can produce at that resting length. The more shortened or contracted the muscles are the less force they can produce.
Force Couple Relationships
Muscle groups moving together to produce movement around a joint.
*altered force couple relationships cause synergistic dominance
Muscle Synergy
co-activation of muscle recruited by a single neural command.
*back, trunk, abdominal, and leg muscles working together to maintain balance while walking.
Synergistic dominance
Synergistic dominance is when the primary mover takes a vacation and helper muscles take over to fill the gap.
*Inhibition of the gluteus maximus may lead to synergistic dominance of the biceps femoris during hip extension
