Muscle contraction and joint movement
The three types of muscle tissue are:
voluntary, involuntary, resting
epimysium, perimysium, endomysium
skeletal, cardiac, smooth
elastic, collagen, fibrous
Skeletal muscles are often called voluntary muscles because:
they contract when stimulated by motor neurons of the central
nervous system
ATP activates skeletal muscles for contraction
the skeletal muscles contain myoneural junctions
connective tissue harnesses generated forces voluntarily
The thin filaments consist of:
a pair of protein strands wound together to form chains of myosin molecules
a helical array of actin molecules
a helical array of myosin molecules
a pair of protein strands together to form chains of actin molecules
The thick filaments consist of:
a helical array of myosin molecules
a helical array of actin molecules
a pair of protein strands wound together to form chains of actin molecules
a pair of protein strands wound together to form chains of myosin molecules
All of the muscle fibers controlled by a single motor neuron constitute a:
sarcomere
motor unit
crossbridge
myoneural junction
The sliding filament theory explains that the physical change that takes place during contraction is that:
the thick filaments are sliding toward the center of the sarcomere alongside the thin filaments
the thin filaments are sliding toward the center of the sarcomere alongside the thick filaments
the Z lines are sliding toward the H zone
the thick and thin filaments are sliding toward the center of the sarcomere together
Troponin and tropomyosin are two proteins that can prevent the contractile process by:
inactivating the myosin to prevent cross-bridging
causing the release of calcium from the sacs of the
sarcoplasmic reticulum
covering the active site and blocking the actin-myosin
interaction
combining with calcium to prevent active site binding
The amount of tension produced by an individual muscle fiber ultimately depends on the:
number of pivoting crossbridges
number of contracting sarcomeres
number of calcium ions released
all-or-none principle
Which type of muscle fiber would be dominant in a muscle like the gastrocnemius, a calf muscle that contracts during standing and
walking?
intermediate fibers
slow fibers
fast fibers
white fibers
Extensive blood vessels, mitochondria, and myoglobin are found in the greatest concentration in:
type II fibers
fast fibers
slow fibers
intermediate fibers
Which of the following could cause muscle atrophy?
wearing a cast on a broken limb
a lack of regular stimulation of muscle fibers
paralysis
all of the above
What type(s) of muscle tissue do(es) not contain sarcomeres?
cardiac
skeletal
smooth
all of the above
The order of the sequential-cyclic reactions that occur at an active site during cross-bridging is:
attach, pivot, detach, return
attach, return, detach, pivot
attach, return, pivot, detach
attach, detach, pivot, return
The area of the A band in the sarcomere consists of:
M line, H band, zone of overlap
thin filaments only
Z line, H band, M line
overlapping thick and thin filaments