With muscular dystrophy ________.
Muscle fibers degenerate and atrophy
which muscle cells have the greatest ability to regenerate?
Smooth
Most muscles contain ___________.
a mixture of fiber types
fatigued muscle cells that recover rapidly are the products of__________.
intense exercise of short duration
The strongest muscle contractions are normally achieved by __________.
increasing the stimulation p to the maximal stimulus
Which of the following would be recruited later in muscle stimulation when contractile strength increases ?
Motor units with larger, less excitable neurons
Which of the following is not a usual result of resistance exercise ?
increase in the number of muscle cells
In skeletal muscle contraction, calcium apparently acts to _______.
remove the blocking action of tropomyosin
Calcium ions bind to the ______ molecule in skeletal muscle cells.
troponin
Myoglobin ______.
stores oxygen in muscle cells
An elaborate network of membranes in skeletal muscle cells that functions in calcium storage is the _______.
Sarcoplasmic reticulum
A sarcomere is _______.
the area between two Z discs
Immediately following the arrival of the stimulus at a skeletal muscle cell there is a short period called the _______ period during which the events o excitation - contraction coupling occur.
Latent
Creatine Phosphate functions in the muscle cell by _____.
storing energy that will be transferred to ADP to resynthesize ATP
After nervous stimulation of the muscle cell has ceased , the calcium _______.
level in the cytoplasm drops
The major function of the sarcoplasmic reticulum in muscle contraction is to _________.
regulate intracellular calcium concentration
The striations of a skeletal muscle cell are produced, for the most part, by _______.
the arrangement of myofilaments
Which of the following are composed of myosin ?
Thick filaments
During muscle contraction, myosin cross brides attach to which active sites ?
actin filaments
Which of the following surrounds the individual muscle cell ?
Endomysium
Smooth muscle that act like skeletal muscles but are controlled by autonomic nerves and hormones are ____?
Multiunit muscles
Rigor mortis occurs because _______?
no ATP is available to release attached actin and myosin molecules
Which of the following does not act as a stimulus to initiate a muscle contraction ?
A change of Temperature
The term aponeurosis refers to
A sheetlike indirect attachment to a skeletal element
The oxygen binding protein found in muscle cells is
myoglobin
The contractile units of skeletal muscles are _______.
myofibrils
The site of calcium regulation in the smooth muscle cell is
calmodulin
One function unit of a skeletal muscle is
a sarcomere
The functional role of the T tubules is to ______.
enhance cellular communication during muscle contraction
The role of calcium ions in muscle contractions is to ______.
bind to regulatory sites on troponin, changing the configuration
The warm-up period required of athletes in order to bring their muscles to peal performance is called _______.
Treppe
The main effect of the warm-up period of athletes, as the muscle contractions increase in strength, is to ________.
enhance the availability of calcium and the efficiency of enzyme systems
During vigorous exercise, there may be insufficient oxygen available to completely break down pyruvic acid for energy. As a result, the pyruvic acid is converted to _____.
Lactic Acid
When a muscle is unable to respond to stimuli temporarily, it is in which of the following periods ?
refractory period
In the isotonic contraction, the muscle ______.
changes in length and moves the "load"
The muscle cell membrane is called the ________.
Sarcolemma
Smooth muscle is significantly different from striated muscle in several ways, Which of the following is true ?
Smooth muscle contracts in a twisting way
The mechanism of contraction in smooth muscle is different from skeletal muscle in that ______.
the site of calcium regulation differs
The cells of single- unit visceral muscle ______.
exhibit spontaneous action potentials
Which of the following statements is not true concerning developmental aspects of muscle ?
There is no biological basis for the difference in strength between women and men.
Which of the following is true about smooth muscle contraction ?
Certain smooth muscle cells can actually divide to increase their numbers
Smooth muscle is characterized by all of the following except _____.
There are more thick filaments than thin filaments
The giant protein titin maintains the organization of the _______ assisting in muscle stretching.
A band
Muscle tissue have all of the following properties except
Secretion
Which of the following statements is true ?
Striated muscle cells are long and cylindrical with many nuclei
An anaerobic metabolic pathway that results in the production of two net ATPs per glucose plus two pyruvic acid molecules is _____.
glycolysis
Muscle tone is _______.
A state of sustained partial contraction
The sliding filament model of contraction involves _______.
actin and myosin sliding past each other and partially overlap
After nervous stimulation stops, ACh in the synaptic cleft is prevented from continuing stimulation of contraction by ___________.
Acetylcholinesterase destroying the ACh
Which of the following is most accurate ?
Muscle tension remains relatively constant during isotonic contraction
The most distinguishing characteristic of muscle tissue is _______.
The ability to transform Chemical energy into mechanical energy
Three discrete types of muscle fibers are identified on the basis of their size, speed, and endurance , Which of the following athletic endeavors best represents the use of red fibers ?
A long, relaxing swim
Of the following muscle types, which has only one nucleus , no sarcomeres, and rare gap junctions ?
Multiunit smooth muscle
Hypothetically, if a muscle were stretched to the point where thick and thin filaments no longer overlapped ________.
no muscle tension could be gathered
An individual has just ingested a chemical that binds irreversibly to the ACh receptors in the sarcolemma. By itself it does not alter membrane potential , yet prevents normal neurotransmitter binding. ignoring the effects on nay other system, the consequence to skeletal muscle would be ....
no contraction at all by nervous mechanisms, but contraction if stimulated by an external electrode