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
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.
