Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
89 Cards in this Set
- Front
- Back
skeletal muscle
|
Striated muscle attached to bone or skin and responsible for skeletal movements and facial expression; controlled by somatic nervous system
|
|
smooth muscle
|
Nonstriated muscle that surrounds hollow organs and tubes; see also multiunit smooth muscle, single-unit smooth muscle
|
|
cardiac muscle
|
Heart muscle
|
|
muscle fiber
|
Muscle cell
|
|
myoblasts
|
Embryological cell that gives rise to muscle fibers
|
|
satellite cells
|
Undifferentiated cells found within skeletal muscle tissue that can fuse and develop into new muscle fibers following muscle injury.
|
|
hypertrophy
|
Enlargement of a tissue or organ due to increased cell size rather than increased cell number.
|
|
muscle
|
Number of muscle fibers bound together by connective tissue
|
|
tendons
|
Collagen fibre bundle that connects skeletal muscle to bone and transmits muscle contraction force to the bone.
|
|
striated muscle
|
Muscle having transverse banding pattern due to repeating sarcomere structure; see also cardiac muscle, skeletal muscle
|
|
myofibrils
|
Bundle of thick or thin contractile filaments in cytoplasm of striated muscle; myofibrils exhibit a repeating sarcomere pattern along longitudinal axis of muscle.
|
|
sarcomere
|
Repeating structural unit of myofibril; composed of thick and thin filaments; extends between two adjacent Z lines
|
|
thick filaments
|
Myosin filament in muscle cell
|
|
thin filaments
|
Actin filament in muscle cell
|
|
actin
|
Globular contractile protein to which myosin cross-bridges bind; located in muscle thin filaments and in microfilaments of cytoskeleton.
|
|
A band
|
One of the transverse bands making up repeated striations of cardiac and skeletal muscle; region of aligned myosin-containing thick filaments.
|
|
Z line
|
Structure running across myofibril at each end of striated muscle sarcomere; anchors one end of thin filaments and titin
|
|
I band
|
One of transverse bands making up repeating striations of cardiac and skeletal muscle; located between A bands of adjacent sarcomeres and bisected by Z line.
|
|
H zone
|
One of the transverse bands making up striated pattern of cardiac and skeletal muscle; light region that bisects A band.
|
|
M line
|
Transverse stripe occurring at the center of the A band in cardiac and skeletal muscle; location of energy-generating enzymes and proteins connecting adjacent thick filaments.
|
|
titin
|
Protein that extends from the Z line to the thick filaments and M line of skeletal muscle.
|
|
contraction
|
Operation of the force-generating process in a muscle cell.
|
|
relaxation
|
Return of muscle to a low force-generating state, caused by detachment of cross-bridges.
|
|
sliding-filament mechanism
|
Process of muscle contraction in which shortening occurs by thick and thin filaments sliding past each other.
|
|
heavy chains
|
Painrs of large, coiled polypeptides that make up the rod and globular head of a myosin molecule.
|
|
light chains
|
Pair of small polypeotides bound to each globular head of a myosin molecule; function is to modulate contraction.
|
|
cross-bridge cycle
|
Sequence of events between binding of cross-bridge to actin, its release, and reattachment during muscle contraction.
|
|
power stroke
|
The step of a cross-bridge cycle involving physical rotation of the globular head.
|
|
rigor mortis
|
Stiffness of skeletal muscles after death due to failure of cross-bridges to dissociate from actin because of loss of ATP.
|
|
troponin
|
Regulatory protein bound to actin and tropomyosin of striated muscle thin filaments; site of calcium binding that initiates contractile activity
|
|
tropomyosin
|
Regulatory protein capable of reversibly converting binding sites on actin; associated with muscle thin filaments.
|
|
excitation-contraction coupling
|
In muscle fibers, mechanism linking plasma membrane
|
|
sarcoplasmic reticulum
|
Endoplasmic reticulum in muscle fiber; site of storage and release of calcium ions.
|
|
lateral sacs
|
Enlarged region at end of each sarcoplasmic reticulum segment; adjacent to transverse tubule.
|
|
transverse tubule (T-tubule)
|
Tubule extending from striated-muscle plasma membrane into the fiber, passing between opposed sarcoplasmic reticulum segments; conducts muscle action potential into muscle fiber.
|
|
junctional feet foot proteins
|
Large extension of sarcoplasmic reticulum calcium channels (ryanodine receptors), which connect them to the T-tubule membrane and mediate excitation-contraction coupling in skeletal muscle; also known as junctional feet
|
|
dihydropyridine (DHP) receptor
|
Nonconducting calcium channels in the T-tubule membranes of skeletal muscle cells, which act as voltage sensors in excitation-contraction coupling
|
|
ryanodine receptor
|
Calcium-release channel found in the lateral sas of the carcoplasmic reticulum in skeletal muscle cells.
|
|
motor neurons
|
Somatic efferent neuron, which innervates skeletal muscle.
|
|
motor unit
|
Motor neuron plus the muscle fibers it innervates.
|
|
acetylcholine (ACh)
|
A neurotransmitter released by pre- and post-ganglionic parasympathetic neurons, preganglionic sympathetic neurons, somatic neurons, and some CNS neurons.
|
|
motor end plate
|
Specialized region of muscle cell plasma membrane that lies directly under axon terminal of a motor neuron
|
|
neuromuscular junction
|
Synapse-like junction between an axon terminal of an efferent nerve fiber and a skeletal muscle fiber.
|
|
end-plate potential (EPP)
|
Depolarization of motor end plate of skeletal muscle fiber in response to acetylcholine; initiates action potential in muscle plasma membrane
|
|
acetylcholinesterase
|
Enzyme that breaks down acetylcholine into acetic acid and choline.
|
|
tension
|
Force; see also muscle tension
|
|
load
|
External force acting on muscle.
|
|
Isometric contraction
|
Contraction of muscle under conditions in which it develops tension but does not change length
|
|
isotonic
|
Containing the same number of effectively nonpenetrating solute particles as normal extracellular fluid
|
|
Isotonic contraction
|
Contraction of muscle under conditions in which load on the muscle remains constant but muscle shortens
|
|
concentric contraction
|
Muscle activity that involves shortening of muscle length.
|
|
Lengthening contraction (eccentric contraction)
|
Contraction as an external force pulls a muscle to a longer length despite opposing forces generated by the active cross-bridges.
|
|
twitch
|
Mechanical response of muscle to single action potential
|
|
latent period
|
Period lasting several milliseconds between action potential initiation in a muscle fiber and beginning of mechanical activity
|
|
contraction time
|
Time between beginning of force development and peak twitch tension by the muscle.
|
|
summation
|
Increase in muscle tension or shortening in response to rapid, repetitive stimulation relative to single twitch
|
|
tetanus
|
Maintained mechanical response of muscle to high-frequency stimulation; also the disease lockjaw
|
|
unfused tetanus
|
Stimulation of skeletal muscle at a low-to-moderate action potential frequency that results in oscillating, submaximal force
|
|
fused tetanus
|
Skeletal muscle activation in which action potential frequency is sufficiently high to cause a smooth, sustained, maximal strength contraction.
|
|
creatine phosphate (CP)
|
Molecule that transfers phosphate and energy to ADP to generate ATP.
|
|
oxygen debt
|
Decrease in energy reserves during exercise that results in an increase in oxygen consumption and an increased production of ATP by oxidative phosphorylation following the exercise.
|
|
muscle fatigue
|
Decrease in muscle tension with prolonged activity
|
|
Fatigue from high-intensity, short duration exercise is thought to involve at least three different mechanisms
|
Conduction failure, lactic acid buildup, inhibition of cross-bridge cycling
|
|
lactic acid
|
Three-carbon molecule formed by glycolytic pathway in absence of oxygen; dissociates to form lactate and hydrogen ions.
|
|
central command fatigue
|
Muscle fatigue due to failure of appropriate regions of cerebral cortex to excite motor neurons.
|
|
fast fibers
|
Skeletal muscle fiber that contains myosin having high ATPase activity.
|
|
slow fibers
|
Muscle fiber whose myosin has low ATPase activity.
|
|
oxidative fibers
|
Muscle fiber that has numerous mitochondria and therefore a high capacity for exidative phosphorylation; red muscle fiber
|
|
myoglobin
|
Muscle fiber protein that binds oxygen.
|
|
red muscle
|
Muscle having high oxidative capacity and large amount of myoglobin.
|
|
glycolytic fibers
|
Skeletal muscle fiber that has a high concentration of glycolytic enzymes and large glycogen stores; white muscle fiber.
|
|
white muscle
|
Muscle lacking appreciable amounts of myoglobin
|
|
slow-oxidative fibers
|
Type of skeletal muscle fiber that has slow intrinsic contraction speed but fatigues very slowly due to abundant capacity for production of ATP by aerobic oxidative phosphorylation.
|
|
fast-oxidative fiber
|
Type of skeletal muscle fiber that has high intrinsic contraction speed and abundant capacity for production of ATP by aerobic oxidative phosphorylation.
|
|
fast-glycolytic fiber
|
Type of skeletal muscle fiber that has high intrinsic contraction speed and abundant capacity for production of ATP by anaerobic glycolysis.
|
|
recruitment
|
Activation of additional cells in response to increased stimulus strength; increasing the number of active motor units in a muscle.
|
|
flexion
|
Bending a joint
|
|
extension
|
Straightening a joint
|
|
antagonists
|
(muscle) muscle whose action opposes intended movement; (drug) molecule that competes with another for a receptor and binds to the receptor but does not trigger the cells response.
|
|
hypocalcemia
|
The condition of low blood (and interstitial) calcium concentration.
|
|
dense bodies
|
Cytoplasmic structure to which thin filaments of a smooth muscle fiber are anchored.
|
|
myosin light-chain kinase
|
Smooth-muscle protein kinase; when activated by Ca-calmodulin, phosphorylates myosin light chain.
|
|
myosin light-chain phosphatase
|
Enzyme that removes high-energy phosphate from myosin; important in the relaxation of smooth muscle.
|
|
latch state
|
Contractile state of some smooth muscles in which force can be maintained for prolonged periods with very little energy use; cross-bridge cycling slows to the point where thick and thin filaments are effectively latched together.
|
|
smooth muscle tone
|
Smooth-muscle tension due to low-level cross-bridge activity.
|
|
pacemaker potential
|
Spontaneous gradual depolarization to threshold of some nerve and muscle cells plasma membrane
|
|
Varicosity
|
Swollen region of axon; contains neurotransmitter-filled vesicles; analogous to presynaptic ending
|
|
single-unit smooth muscles
|
Smooth muscle that responds to stimulation as single unit because gap junctions join muscle fibers.
|
|
multiunit smooth muscles
|
Smooth muscle that little, if any propagation of electrical activity from fiber to fiber and whose contractile activity is closely coupled to its neural input.
|