Chapter 10 Muscle Tissue Flashcards
muscle tissue consists of cells that are highly specialized for the function of
excitability
contraction
extensibility
the primary functions performed by skeletal muscles are
produce skeletal movement
guard entrances and exits
maintain body temperature
skeletal muscles move the body by
pulling on bones of the skeleton
skeletal muscles are often called voluntary muscles because
they contract when stimulated by motor neurons
three layers of connective tissue supporting each muscle
epimysium
perimysium
endomysium
smallest functional unit of muscle fiber
sarcomere
nerves and blood vessels that supply the muscle fibers are contained within the connective tissues of the
endomysium and perimysium
the thin filaments consist of
a pair of protein strands wound together to form chains of actin molecules
the thick filaments consist of
a helical array of myosin molecules
all of the muscle fibers controlled by a single motor neuron constitute a
motor unit
the tension in a muscle fiber will vary depending on
- structure of sarcomeres
- length of muscle fibers
- number of cross-bridge interactions
the reason there is less precise control over leg muscle compared to the muscle of the eye is
many muscle fibers are controlled by a single motor neuron
the sliding filament theory explains that the physical change that takes place during contraction is
the thin filaments sliding toward center of sarcomere alongside thick filaments
troponin and tropomyosin are two proteins that can prevent the contractile process by
covering the active site and blocking the actin-myosin interaction
the first step in excitation-contraction coupling is
release of calcium ions from cisternae of sarcoplasmic reticulum
the amount of tension produced by an individual muscle fiber ultimately depends on
number of pivoting cross-bridges
skeletal muscle fibers contract most forcefully when stimulated over a
narrow range of resting lengths
the amount of tension produced by a skeletal muscle is controlled by
total number of muscle fibers stimulated
peak tension production occurs when all motor units in the muscle contract in a state of
complete tetanus
in an isotonic contraction…
cross-bridges must produce enough tension to overcome resistance
in an isometric contraction..
tension rises but length of muscle remains constant
a high blood concentration of the enzyme creatine phosphokinase usually indicates
serious muscle damage
mitochondrial activities are relatively efficient, but their rate of ATP generation is limited by
availability of oxygen
during the recovery period, the body’s oxygen demand is
elevated above normal resting levels
three major types of skeletal muscle fibers in the human body
slow
intermediate
fast
extensive blood vessels, mitochondria, and myoglobin are found in the greatest concentration in
slow fibers
the length of time a muscle can continue to contract while supported by mitochondrial activities
aerobic endurance
altering the characteristics of muscle fibers and improving the performance of the cardiovascular system results in improving
aerobic endurance
the property of cardiac muscle that allows it to contract without neural stimulation
automaticity
the type of muscle cell that locks sarcomeres and the resulting striations
smooth
structurally, smooth muscle cells differ from skeletal muscle cells because smooth muscle cells..
lack myofibrils and sarcomeres
smooth muscle tissue differs from other muscle tissue in
excitation-contraction coupling
length-tension relationships
control of contraction
neural, hormonal, or chemical factors can stimulate smooth muscle contraction producing
a decrease in muscle tone
layers of smooth muscle in the reproductive tract of the female are important in
movement of ova
movement of sperm if present
expelling of the fetus at delivery