with All Correct Answers
True or false: Within a particular motor unit, all of the skeletal muscle fibers are of the
same type. - Answer-True
Different motor units in a muscle are recruited in a (specific/non-specific) order. What is
this based on? Which muscle fiber type is always recruited first? - Answer-specific order
based on need; Type I SO
Does every muscle normally consist of one type of muscle fiber or a mixture? - Answer-
Mixture
Total number of muscle fibers generally (changes/does not change) with exercise. What
is this called?
More likely is that the growth of muscles from exercise is the enlargement of ____ cells.
This is called ____. - Answer-does not change; hyperplasia; existing; hypertrophy
Wasting away of muscles; this can be caused by disuse or severing of the ____ supply
If you sever the nerve supply to your muscle, if it rebuilt with ____ tissue. This rebuilding
(is/is not) reversible. - Answer-Atrophy; nerve; connective; is not
Hypertrophy is an increase in the ____ of muscle fibers. This happens by adding more
components to the fiber. - Answer-diameter
Anabolic steroids mimic ____ in the body. - Answer-testosterone
Skeletal muscle starts to be replaced by ____ starting at the third to fourth decade. As
muscle tissues age, reflexes (speed up/slow down) and maximal strength
(decreases/increases). - Answer-fat; slow down; decreases
Change in muscle fiber type to ____ fibers may be due to the lack of ____ or may be
the result of ____. - Answer-slow oxidative (SO/Type I); use; aging
Muscle shortens to produce force and movement - Answer-Concentric
Muscle lengthens while maintaining force and movement - Answer-Eccentric
, Tension is generated; no muscle shortening; no movement - Answer-Isometric
The most muscular injuries occur during which type of contraction? - Answer-Eccentric
Name 6 factors that affect force production:
1. Number of ____ activated
2. ____ of motor units activated
3. Size of ____
4. Muscle ____
5. Joint ____
6. ____ of action - Answer-motor units; type; muscle; length; angle; speed
Cross bridge interaction impacts the force production by a muscle. If there is more
interaction, (more/less) force is generated. But too much interaction is not good
because the sarcomere are crumpled between 2 ____. Need a happy medium for
amount of cross bridge interaction. ____ length is pretty much at an optimal zone of
overlap (it is between ____ and ____% of optimum), meaning the muscle fiber can
develop maximal ____. - Answer-more; Z-discs; Resting; 70 and 130; tension
Optimal joint angle is ____ degrees. Change in joint angle changes the zone of ____ in
the sarcomeres. - Answer-90; overlap
Force-velocity curve demonstrates the idea, which we already know, that the
(lighter/heavier) the load, the quicker we can shorten the muscle; and the
(lighter/heavier) the load, the slower we can shorten the muscle. - Answer-lighter;
heavier
Second stimulus applied before muscle has completely relaxed after the previous
stimulus; results in increased strength of contraction - Answer-Wave summation
Sustained muscle contraction that permits partial relaxation between stimuli - Answer-
Incomplete/unfused tetanus
Sustained contraction with no relaxation between stimuli - Answer-Complete/fused
tetanus
The wave summation and both types of tetanus occur when additional Ca++ is released
from the ____ while levels in the ____ are still elevated from the initial stimulus. -
Answer-SR; sarcoplasm
Most of our smooth, sustained, voluntary contractions come from ____/____ tetanus
and the ____ in different motor units, causing motor units to contract at different times. -
Answer-incomplete/unfused; asynchrony
____ muscle is that primarily attached to bones. It is (striated/non-striated) and
(voluntary/involuntary. - Answer-Skeletal; striated; voluntary