Question | Answer |
Ability of skeletal muscle to shorten with force. | Contractility |
The capacity of skeletal muscle to respond to a stimulus. | Excitability |
The ability to be stretched. | Extensibility |
Ability to recoil to their original resting length after they have been stretched. | Elasticity |
Connective tissue sheath that covers the skeletal muscle. | Epimysium |
Another connective tissue located outside the epimysium | Fascia |
Loose connective tissue that surrounds the bundles of muscle fibers | Perimysium |
Muscle cells | Fibers |
Connective tissue sheet that surrounds fibers | Endomysium |
Threadlike structure that extends from one end of the fiber to the other | Myofibrils |
Actin | thin myofilaments |
Myosin | thick myofilaments |
Basic structural and functional unit of the muscle | Sarcomeres |
Charge difference across the membrane | Resting membrane potential |
Nerve cells that carry action potentials to skeletal muscle fibers | Motor neurons |
enlarged nerve terminal | Presynaptic terminal |
space between the presynaptic terminal and the muscle cell | Synaptic cleft |
the muscle fiber | Postsynaptic terminal |
Each presynaptic terminal contains | synaptic vesicles |
secreted from the synaptic vesicles | acetylcholine |
breaks down acetylcholine | acetylcholinesterase |
sliding of actin myofilaments past myosin myofilaments during contraction | sliding filament mechanism |
a contraction of an entire muscle in response to a stimulus that causes the action potential in one or more muscle fibers. | Muscle twitch |
point when the muscle fiber will contract maximally | Threshold |
time between application of a stimulus to a motor neuron and the beginning of a contraction | Lag phase |
Muscle remains contracted without relaxing | Tetany |
Increase in number of motor units being activated | Recruitment |
Less stable adenosine phosphate; 3 phosphates | ATP |
More stable adenosine phosphate; 2 phosphates | ADP |
High energy molecule | Creatine Phosphate |
Anaerobic respiration | Without Oxygen |
Aerobic respiration | With Oxygen |
Amount of oxygen needed in chemical reactions to convert lactic acid to glucose | Oxygen debt |
When ATP is used during muscle contraction faster than it can be produced in the muscle cells | Muscle fatigue |
equal distance; length of the muscle does not change, but the amount of tension increases during the contraction process | Isometric |
equal tension; amount of tension produced by the muscle is constant during contraction, but the length of muscle changes | Isotonic |
Constant tension produced by muscles of the body for long periods of time | Muscle tone |
Raises eyebrows | Occipitofrontalis |
Closes the eyelids | Orbicularis oculi |
puckers the lips | Orbicularis oris |
Flattens the cheeks. Trumpeter’s muscle. | Buccinator |
Kissing Muscles | Buccinator and Orbicularis oris |
Smiling muscle | Zygomaticus |
Sneering | Levator labii superioris |
Frowning | Depressor anguli oris |
4 pairs of mastication muscles | 2 pair of pterygoids, temporalis, and masseter. |
change the shape of the tongue | Intrinsic Tongue Muscles |
move the tongue | Extrinsic Tongue Muscles |
lateral neck muscle and prime mover | Sternocleidomastoid |
most stationary end of the muscle | origin |
portion of the muscle between the origin and the insertion | belly |
end of the muscle undergoing the greatest movement | insertion |
Muscles that work together to accomplish specific movements | synergists |
Muscles that work in opposition to one another | antagonists |
Among a group of synergists, if one muscle plays the major role in accomplishing the desired movement | prime mover |
contract quickly and fatigue quickly | Fast-twitch fibers |
contract more slowly | Slow-twitch fibers |
group of muscles on each side of the back | Erector spinae |
rotates scapula | Trapezius |
pulls scapula anteriorly | Serratus anterior |
The arm is attached to the thorax by the | pectoralis major and latissimus dorsi muscles. |
adducts and flexes the arm | Pectoralis major |
medially rotates, adducts, and powerfully extends the arm. “Swimmer muscles” | Latissimus dorsi |
attaches the humerus to the scapula and clavicle, and is the major abductor of the upper limb | Deltoid |
extends the forearm. | Triceps brachii |
flexes the forearm | Biceps brachii |
flexes forearm | Brachialis |
flexes and supinates the forearm. | Brachioradialis |
flexes the wrist | Flexor carpi |
extends the wrist | Extensor carpi |
flexes the fingers | Flexor digitorum |
extends the fingers. | Extensor digitorum |
extends the leg; anterior thigh muscles | Quadriceps femoris |
“tailors muscle”; flexes the thigh | Sartorius |
posterior thigh muscles | Hamstring muscles |