ana 4

enzyme that breaks down acetycholine not permeable to Na+(sodium) but now it is permeable to K+(potassium)

• returns to the resting potential
• impulse move along the cell membrane down the T-tubule
• to the sarcoplasmic reticulim

when the impulse gets to the reticulum is causes calcium ions which have been stored there to be released to the cytoplasm

• then the calcium binds to the troponin which causes the tropomyosin to shift and expose the binding myosin
• this binds the sites on the actin to the actin and will pull the actin filaments inward

the amount of oxygen that needs to be paid back

an individual muscle fiber will contract to its fullest extent or not at all

any force that affects the excitability of a muscle or a nerve

the weakest stimulus that can excite  a muscle to contract

will not initial contraction

a stimulus that excites all the motor units of the muscle

• time after a stimulus during which a 2nd stimulus will not cause a contraction
• repolarization has to not occur

a record of a muscle contraction

between the application of the stimulus and the beginning of the contraction

shortening muscle

muscle is lengthening

when 2 stimuli are applied and the 2nd is delayed until the refractory period is over

skeletal muscle will respond to both stimuli

if 2nd stimuli is applied after refractory but before it finishes refracting it will be stronger than the 1st

the increased strength of the contraction

results when the stimuli id followed in rapid succession

a sustained forceful contraction without relaxation resulting from a series of stimuli on the rapid succession

the continual level of some degree of contraction of a muscle

condition in which a muscle contracts more forcefully after its contracted several times

action in which the muscle tone or tension remains the same but the length changes movement

the tension changes but the length does not move "no movement"

• only in the heart
• striated, branched, involuntary
• differences
• 1.intercalated discs
• transverse thinking of the sarcolemma where the fibers connect
• low electrical resistance and impulse can be conducted from the cell
• 2. times of contraction
• 3.source of stimulation

• non-striated, cells are spindle shaped with a single nucleus
• ex. walls of the stomach
• blood vessels
• still contain actin and myosin but not as orderly arranges