11.5 – Behavior of whole muscles Flashcards
which can be measured by attaching stimulating electrodes to a nerve-muscle preparation and a recording device?
muscle strength
the minimum voltage necessary to generate an action potential is called the ___
threshold
what type of tension develops during the latent period of muscle contraction?
internal tension
on a myogram, how does the relaxation phase compare to the contraction phase?
the relaxation phase is longer
a record of the timing and strength of a muscle’s contraction is called a(n) ___
myogram
stimulus frequency affects the sarcoplasmic concentration of which of the following?
calcium
what is threshold, as applied to muscle physiology?
the minimum voltage necessary to generate an action potential
T or F:
cool muscles contract more strongly than warm ones
F
warm muscles contract more strongly
what does the latent period on a my-gram indicate?
the time period b/n the stimulus and the twitch
at a constant stimulus voltage, how can one increase the twitch strength?
use a higher frequency of stimulation
which occurs during the relaxation phase of a myogram?
muscle tension declines
T or F:
recruitment occurs when more nerve fibers excite more motor units
true
recruitment occurs when more nerve fibers excite more motor units
which can be measured by attaching stimulating electrodes to a nerve-muscle preparation and a recording device?
muscle strength
which affect twitch strength?
how stretched the muscle was just before it was stimulated
muscle fatigue
temp of the muscle
stimulation frequency
what temp would result in a stronger twitch?
warmer temps
what produces incomplete tetanus?
temporal summation
how would high frequency stimuli at a constant voltage affect twitch strength?
it would increase
(high frequency stimulation produces stronger twitches than low-frequency stimulation)
what is it called when stimulus strength increases, increasing the number of motor neurons excited which, in turn, increases the number of motor units firing?
multiple motor unit summation
in which condition are stimuli so frequent that the muscle cannot relax, and the muscle twitches fuse into a smooth prolonged contraction?
tetanus
a record of the timing and strength of a muscle’s contraction is called a(n) ___
myogram
which type of contraction maintains joint stability and posture?
isometric
stimulus frequency affects the sarcoplasmic concentration of which of the following?
calcium
in what type of contraction does the internal tension build until it overcomes resistance and the muscle moves the load?
isotonic
temporal summation leads to a state of fluttering contraction known as what?
incomplete tetanus
at a constant stimulus voltage, how can one increase the twitch strength?
use a higher frequency of stimulation
which is not naturally seen in the muscles of the body?
complete tetanus
when lifting something heavy, which type of contraction occurs first?
isometric
isometric contraction is…
contraction w/o a change in length
isotonic contraction is…
contraction w/ a change in length but no change in tension
a muscle shortens as it maintains tension in a what type of contraction?
concentric
what produces incomplete tetanus?
temporal summation
in which condition are stimuli so frequent that the muscle twitches fuse into a smooth prolonged contraction?
tetanus
