|
Not a purpose of the excess postexercise oxygen consumption in muscle |
to neutralize carbon dioxide buildup |
|
Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source? |
skeletal muscle |
|
Which muscles can contract without the need for nervous stimulation? |
smooth and cardiac muscle |
|
80% of the lactic acid produced by skeletal muscle is converted to pyruvic acid |
by the kidneys |
|
During muscle contraction, a single myosin head consumes ATP at a rate of about |
5 ATP per second. |
|
The term for shortening of a muscle while maintaining constant tension is |
isotonic contraction. |
|
Which fibers are primarily responsible for producing lactic acid? |
type IIB fast glycolytic fibers |
|
Michael Jordan was arguable the best player in professional basketball history. Scientifically one would expect him to have highly developed |
white fibers. |
|
Where would you expect to find numerous gap junctions in muscular tissue? |
intercalated discs of cardiac muscle |
|
The contraction strength of smooth muscle is relatively independent of its resting length partly because |
it does not have sarcomeres. |
|
In comparison to skeletal muscle, smooth muscle |
contracts and relaxes more slowly. |
|
Which of the following is very important for muscle to continue contraction during anaerobic respiration? |
myokinase |
|
The minimum stimulus needed to cause muscle contraction is called |
the threshold |
|
If one nerve stimulus arrives at a muscle fiber so soon that the fiber has only partially relaxed from the previous twitch, the most likely result will be |
incomplete tetanus. |
|
Which is true concerning isotonic eccentric contraction? |
The muscle lengthens but tension remains constant. |
|
Which of the following has the largest mitochondria? |
cardiac muscle |
|
One somatic motor neuron is stimulated by how many muscle fibers? |
0 |
|
To stimulate muscle contraction, acetylcholine is released from the ____ into the synaptic cleft. |
synaptic knob |
|
The absence or inhibition of acetylcholinesterase at a synapse would lead to what? |
tetanus |
|
Which statement best describes the goal of medications used to treat myasthenia gravis? |
to inhibit the function of cholinesterase |
|
The process of bringing more motor units into use during a muscle contraction is called |
recruitment. |
|
Aerobic respiration produces approximately ____ more ATPs per glucose molecule than glycolysis does. |
36 |
|
Athletes who train at high altitudes increase their red blood cell count and thus increase their oxygen supply during exercise. Increased oxygen supply results in |
longer aerobic respiration |
|
Cardiac muscle has very little capacity for regeneration because it lacks |
satellite cells |
|
Which of the following would be caused by contraction of smooth muscle? |
goose bumps |
|
The triads of a muscle fiber consist of |
two terminal cisternae and one T tubule. |
|
As you are lifting a box, someone places extra weight on top of it. For your muscle to continue contraction and lifting the box, the muscle must |
recruit more muscle fibers. |
|
The protein that acts as a calcium receptor in skeletal muscle is |
troponin. |
|
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilator. These drugs |
prevent calcium from entering smooth muscle, thus allowing the muscle to relax. |
|
Exposure o Clostridium tetani causes continuous release of acetylcholine. What effect does this have on smooth muscle? |
no effect |
|
Dystrophin, the protein that is defective in muscular dystrophy is normally found |
between the outermost myofilaments and the sarcolemma of a muscle fiber. |
|
A reason that muscle twitches become progressively stronger in treppe is |
Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it. |
|
The purpose of varicosities in motor nerve fibers in muscle physiology is |
to release neurotransmitter onto smooth muscle cells. |
|
Creatine kinase |
catalyzes the transfer of phosphate from CP to ADP |
|
Release of acetylcholine at a neuromuscular junction |
increases permeability of the sarcolemma to Na+ |
|
Which of the following best describes the resting membrane potential (RMP)? |
The intracellular environment is negatively charged. |
|
The sarcolemma of a resting muscle fiber is most permeable to |
potassium. |
|
What is the purpose of the triad? |
The triad allows for Ca2+ release when a muscle fiber is excited. |
|
Which of the following individuals would have more mitochondria in her skeletal muscle? |
a 22-year-old football player |
|
Which of the following systems would provide energy for a racquetball player? |
the phosphagen system |
|
Loss of muscle mass from lack of activity is termed |
atrophy |
|
Which of the following is not a characteristic of a muscle cell? |
plasticity |
|
Collagen is |
elastic. |
|
A myofilament that flanks a thick filament and anchors it to a Z disc is called |
an elastic filament. |
|
The bladder’s ability to greatly distend and return to normal tension is due to the ____ of smooth muscles. |
plasticity |
|
A skeletal muscle generates the greatest tension when it is |
partially stretched before being stimulated. |
|
A volleyball player depends on the gastrocnemius muscles for plantar flexion, whereas a marathon runner depends more on the soleus muscles for the same action. This is because the soleus muscles |
make more use of aerobic respiration. |
|
In skeletal muscle, alternating light and dark bands are termed |
striations. |
|
The training regimen of a competitive weight lifter is designed partly to |
increase the average number of myofibrils per muscle fiber. |
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