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muscle chapter
Question | Answer |
---|---|
ability of skeletal muscle to shorten with force | contractility |
capacity of skeletal muscle to respond to a stimulus | excitability |
ability to be stretched | extensibility |
ability to recoil to their original resting length after they have been stretched | elasticity |
connective tissue sheath that surrounds each skeletal muscle | epimysium |
connective tissue located outside the epimysium that surrounds and separates muscles | fascia |
numerous visible bundles that make up the composition of a muscle | fascicle |
loose connective tissue that surrounds muscle fascicle | perimysium |
single muscle cells that make up fasciculi | fibers |
connective tissue sheath that surrounds each fiber | endomysium |
threadlike structure that extends from one end of the fiber to the other | myofibril |
thin myofilaments; resemble pearls twisted together | actin myofilaments |
thick myofilaments; resemble bundles of minute golf clubs | myosin myofilaments |
basic structural and functional unit of the muscle | sarcomere |
charge difference across the membrane | resting membrane potential |
brief reversal back of the charge | action potential |
nerve cells that carry action potentials to skeletal muscle fibers | motor neurons |
what is formed by an enlarged nerve terminal resting in an indentation of the muscle cell membrane | neuromusclular junction |
another term for neuromusclular junction | synapse |
a single motor neuron and all the skeletal muscle fibers it innervates | muscle unit |
enlarged nerve terminal | presynaptic terminal |
space between the presynaptic terminal and the muscle cell | synaptic cleft |
sliding of actin myofilaments past myosin myofilaments during contraction | sliding filament mechanism |
contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers | muscle twitch |
the time between application of a stimulus to a motor neuron and the beginning of a contraction | lag phase |
time of contraction | contraction phase |
time during which the muscle relaxes | relaxation phase |
where the muscle remains contracted without relaxing | tetany |
increase in number of motor units being activated | recruitment |
needed for energy for muscle contraction | ATP |
where is ATP produced | mitochondria |
what does ATP degenerate to | ADP |
another high-energy molecule that is stored when muscle cells can't stockpile ATP | creatine phosphate |
without oxygen | anaerobic respiration |
with oxygen (more efficient) | aerobic respiration |
after intense exercise, what does the respiration rate do? | remains elevated |
amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate stores in muscle cells | oxygen debt |
what results when ATP is used during muscle contraction faster than it can be produced in the muscle cells | muscle fatigue |
length of the muscle does not change, but the amount of tension increases during the contraction process | isometric |
amount of tension produced by the muscle is constant during contraction, but the length of the muscle changes | isotonic |
keeps head up and back straight | muscle tone |
what can contract quickly and fatigue quickly? | fast-twitch fibers |
what can contract more slowly and is more resistant to fatigue | slow-twitch fibers |
points of attachment of each muscle | origin, insertion |
what is the muscle connected to at the point of attachment | to the bone, by a tendon |
most stationary end of the muscle | origin |
end of the muscle undergoing the greatest movement | insertion |
portion of the muscle between the origin and the insertion | belly |
true or false, muscles can have multiple origins or head? | true |
muscles that work together to accomplish specific movements | synergists |
muscles that work in opposition to one another | antagonists |
what is the erector spinae responsible for | keeping the back straight and the body erect |
group of muscles on each side of the back | erector spinae |
muscles that move the thorax | thoracic muscles |
elevates the ribs during inspiation | external intercostals |
contracts during forced expiration | internal intercostals |
dome-shaped muscle that aids in breathing | diaphragm |
area of abdominal wall that consists of white connective tissue | linea alba |
where is the rectus abdominis muscle located? | on each side of the linea alba |
at how many locations do tendinous inscriptions cross the rectus abdominis? | three or more |
rotates scapula | trapezius |
pulls scapula anteriorly | serratus anterior |
what attaches the arm to the thorax? | pectoralis major and latissimus dorsi muscles |
adducts and flexes the arm | pectoralis major |
considered the "swimmer muscles" | latissimus dorsi |
major abductor of the upper limb | deltoid |
extends the forearm | triceps brachii |
flexes the forearm; occupies anterior compartment | biceps brachii |
flexes forearm | brachialis |
flexes and supinates the forearm | brachioradialis |
flexes wrist | flexor carpi |
extends the wrist | extensor carpi |
flexes the fingers | flexor digitorum |
extends the fingers | extensor digitorum |
number of intrinsic hand muscles | 19 |
strong band of fibrous connective tissue that covers flexor | retinaculum |
buttocks | gluteus maximus |
extends the leg; anterior thigh muscles | quadriceps femoris |
flexes the thigh | sartorius |
posterior thigh muscles | hamstring muscles |
form calf muscle | gastrocnemius and soleus |
flexes foot and toes | calcaneal tendon |
lateral muscles of leg | peroneus muscles |
muscles that flex, extend, abduct, and adduct the toes | intrinsic foot muscles |
number of intrinsic foot muscles | 20 |