Chapter 11 Muscular Tissue
Extensibility refers to the ability of a muscle to stretch.
A dark band formed by parallel thick filaments that partly overlap the thin filaments is known as an H band
The sarcoplasmic reticulum is the smooth ER of a muscle fiber.
Clinically, dystrophin is the most important noncontractile protein to occur in muscle fibers
The sliding filament theory of muscle contraction has emerged from research only in the last 10 to 15 years.
A deficiency of Ach receptors leads to muscle paralysis in myasthenia gravis
An isometric contraction does not change muscle length
Some smooth muscle is autorhythmic.
Which one is most dependent on extracellular Ca2+?
Which muscle tissue contracts in response to conscious nervous stimulation?
Which does not exhibit striations
Which has the widest T tubules?
Which muscle tissue has the greatest capacity for regeneration?
Which acts during a power stroke?
Which is predominately made up of myosin?
Which band contains overlapping thick and thin filaments?
to neutralize carbon dioxide buildup
Which of the following is not a purpose of the excess postexercise oxygen consumption in muscle?
Which muscle type depends solely on the sarcoplasmic reticulum as its calcium source?
smooth and cardiac muscle
Which muscle(s) can contract without the need for nervous stimulation?
in the liver
Where is lactic acid converted to pyruvic acid?
5 ATP per second
During muscle contraction, a single myosin head consumes ATP at a rate of about
The term for shortening of a muscle while maintaining constant tension is
type IIB fast glycolytic fibers
Which fibers are primarily responsible for producing lactic acid?
Michael Jordan was arguably the best player in professional basketball history. Scientifically one would expect him to have highly developed
intercalated discs of cardiac muscle
Where would you expect to find numerous gap junctions in muscular tissue?
it does not have Z discs
The contraction strength of smooth muscle is relatively independent of its resting length partly because
contracts more rapidly but relaxes more slowly.
In comparison to skeletal muscle, smooth muscle
Which of the following is very important for muscle to continue contraction during anaerobic respiration?
The minimum stimulus needed to cause muscle contraction is called
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
The muscle lengthens but tension remains constant.
Which of the following is true concerning isotonic eccentric contraction?
Which of the following has the largest mitochondria?
One somatic motor neuron is stimulated by how many muscle fibers?
To stimulate muscle contraction, acetylcholine is released from the ___________ into the
The absence or inhibition of AChE at a synapse would lead to which of the following?
to inhibit the function of cholinesterase
Which statement best describes the goal of medications used to treat myasthenia gravis?
A single high-voltage stimulation of a muscle will result in
Aerobic respiration produces approximately _____ more ATPs per glucose molecule than glycolysis does
longer aerobic respiration
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
Cardiac muscle has very little capacity for regeneration because it lacks
Which of the following would be caused by contraction of smooth muscle?
two terminal cisternae and one T tubule.
The triads of a muscle fiber consist of
recruit more muscle fibers.
As you are lifting a box someone places extra weight on top of it. For your muscle to continue contracting and lifting the box, the muscle must
The protein that acts as a calcium receptor in skeletal muscle is
prevent calcium from entering smooth muscle, thus allowing the muscle to relax
Drugs called calcium channel blockers may be used to lower blood pressure by causing arteries to vasodilate. These drugs
Exposure to Clostridium tetani causes continuous release of ACh. What effect does this have on smooth muscle?
between the thin myofilaments and the sarcolemma of a muscle fiber.
Dystrophin, the protein that is defective in muscular dystrophy, is normally found
Ca2+ accumulates in the sarcoplasm faster than the sarcoplasmic reticulum can reabsorb it.
A reason that muscle twitches become progressively stronger in treppe is
to release norepinephrine.
The purpose of varicosities in muscle physiology is
donates one of its phosphate groups to ADP.
increases permeability of the sarcolemma.
Release of ACh
The intracellular environment is negatively charged.
Which of the following best describes the resting membrane potential (RMP)?
The sarcolemma of a resting muscle fiber is most permeable to
. The triad allows for Ca2+ release when a muscle fiber is excited.
What is the purpose of the triad?
a 22-year-old football player
Which of the following individuals would have more mitochondria in his skeletal muscle?
the phosphagen system
Which of the following systems would provide energy for a racquetball player?
Loss of muscle mass from lack of activity is termed
Which of the following is not a characteristic of a muscle cell?
an elastic filament.
A myofilament that flanks a thick filament and anchors it to a Z disc is called
The bladder's ability to greatly distend and return to normal tension is due to the ___ of smooth muscles
partially stretched before being stimulated
A skeletal muscle generates the greatest tension when it is
make more use of aerobic respiration.
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
In a relaxed muscle fiber, the active sites of actin are blocked by
In skeletal muscle, alternating light and dark bands are termed
increase the average number of myofibrils per muscle fiber.
The training regimen of a competitive weight lifter is designed partly to