Physiology: muscle Flashcards
Physiology: muscle
muscular fascia from deep to superficial
- Endomysium (covers individual fiber)
- Perimysium (covers individual bundles)
- Epimysium (surrounds entire muscle)
Physiology: muscle
Skeletal muscle fibers have a cell membrane and many organelles.
- Cytoplasm = sarcoplasm
- Endoplasmic reticulum = sarcoplasmic reticulum
- Cell membrane = _______
sarcolemma
Physiology: muscle
Protein filaments within each sarcomere are called
actin (thin; attached to Z-lines) and myosin (thick; heads)
Physiology: muscle
Which part of muscle fiber contraction requires ATP?
Does relaxation require ATP?
- The release of myosin heads from actin requires ATP binding.
- Energy from ATP is required for the power stroke.
- Relaxation does not directly require ATP, but relaxation cannot occur unless Ca++ is pumped back into the sarcoplasmic reticulum using a Ca++ATPase
Physiology: muscle
energy for sliding filament theory comes from
- Stored ATP in muscles
- Regeneration of ATP from stored creatine phosphate (FAST! 1st 15 seconds, 100-meter run; from phosphocreatine stored in muscle cells)
- Regeneration of ATP from anaerobic breakdown of glucose: anaerobic glycolysis (50% slower; 30-40 second of muscle contraction; from carbohydrates only; lactic acid)
- Regeneration of ATP from aerobic breakdown of glucose (long duration exercise; yields most ATP; requires fats, carbs, and glucose)
Physiology: muscle
One motor neuron and all the muscle fibers that it controls
motor unit
- Small motor units produce fine movements
- Large motor units produce gross movements
Physiology: muscle
Each actin molecule is a binding site to which a ______ ______ _______ can attach
myosin cross bridge
Physiology: muscle
types of muscle fibers
- Slow fibers: type I, low glycolytic, high oxidative (oxidative phosphorylation)
- Fast fatigue-resistance: type IIa, high glycolytic, high oxidative.
- Fast fatigable: type IIb, high glycolytic, low oxidative
Physiology: muscle
the golden rule in types of muscle fibers
Type I muscle fibers have more mitochondria
- Type I: aerobic, red, high oxidative, slow twitch, long contraction
- Type II: anaerobic, white, high glycolytic, fast twitch, short contraction
Physiology: muscle
active insufficiency
- due to a muscle being too short or too long
- both result in decreased mm contraction
Physiology: muscle
Concentric muscle force _______ proportional to velocity muscle shortening
inversely
Physiology: muscle
Eccentric muscle force _____ proportional to velocity muscle lengthening
directly
Physiology: muscle
muscle spindles are sensitive to
amount and speed of lengthening (stretching of a muscle)
Physiology: muscle
Since a muscle can be overstretched and torn impulse from the muscle spindle causes the spinal cord to initiate a reflex contraction. Called…
muscle spindle stretch reflex
Physiology: muscle
the gamma motor system
sets the sensitivity of the muscle spindle
- Gamma LMN travels from the SC to the intrafusal fiber of the muscle spindle
- Gamma LMN can contract the muscle spindle making it tauter and more sensitive to stretch
Physiology: muscle
the alpha motor system…
directs actual muscle contraction by directing the extrafusal fibers of the muscle to contract
Physiology: muscle
Resting tone of muscle set by
the gamma motor system
When the gamma motor systems tightens
the muscle spindles within the muscles the
muscle spindles more readily trigger
stretch reflex
Physiology: muscle
Golgi tendon organs are sensitive to
- tension: pulling forces on the tendon
- If there is too much muscle tension the golgi tendon organ will inhibit the muscle from creating any force (via a reflex arc), thus protecting you from injuring itself.
