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Ch6 Muscles
Question | Answer |
---|---|
the ability of skeletal muscle to shorten with force | Contractility |
the capacity of skeletal muscle the 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 |
Four major skeletal muscle characteristics | Contractility, Excitability, Extensibility, and Elasticity |
Each skeletal muscle is surrounded by a connective tissue sheath called the | Epimysium |
Connective tissue located outside the epimysium | Fascia |
A muscle is composed of numerous visible bundles called | Muscle Fasciculi |
Muscle fasciculi are surrounded by loose connective tissue called the | Perimysium |
Muscle cells | Fibers |
Each fiber is surrounded by a connective tissue sheath called the | Endomysium |
The cytoplasm of each fiber is filled with | Myofibrils |
Myofibrils consist of 2 major kinds of protein fibers | Actin and myosin myofilaments |
Thin myofilaments, pearls twisted together | Actin |
Thick myofilaments, bundles of golf clubs | Myosin |
Actin and myosin myofilaments form highly ordered units called | Sarcomeres |
Basic structural and functional unity of the muscle | Sarcomere |
Z line to Z line | Sarcomere |
Light area on each side of the z line | I band |
i bands consist of | actin |
darker region in each sarcomere | a band |
the a band extends the length of the | myosin |
the light area in the middle of the sarcomere | h zone |
h zone consists of | myosin |
dark staining band in the center of the sarcomere | m line |
charge difference across the membrane | resting membrane potential |
the brief reversal back of the charge | action potential |
nerve cells that carry action potentials to the skeletal muscle fibers | motor nuerons |
each branch that connects to the muscle forms a | neuromuscular junction |
another term for neuromuscular junction | synapse |
a single motor neuron and all the skeletal fibers it innervates | motor unit |
many motor units | single muscle |
formed by an enlarged nerve terminal resting in an identification of the muscle cell membrane | neuromuscular junction |
enlarged nerve terminal | presynaptic terminal |
space between the presynaptic terminal and the muscle cell | synaptic cleft |
muscle fiber | postsynaptic terminal |
each presynaptic terminal contains | synaptic vesicles |
synaptic vesicles secrete a neurotransmitter called | acetylcholine |
enzymes that break down acetocholine | acetylcholinesterase |
Occurs as actin and myosin myofilaments slide past one another causing the sarcomeres to shorten | Contraction |
The 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 |
A muscle fiber will not respond to stimulus until that stimulus reaches a level called | Threshold |
The muscle fiber will contract maximally | All-Or-None Response |
The time between application of a stimulus to a motor neuron and the beginning of a contraction | Lag phase |
The time of the contraction | Contraction phase |
The time during which the muscle relaxes | Relaxation Phase |
Where the muscle remains contracted without relaxing | Tetany |
The increase in number of motor units being activated | Recruitment |
Needed for energy for muscle contraction | ATP (adenosine triphosphate |
ATP is produced in the | Mitochondria |
ATP degenerates to the more stable plus phosphate | ADP (adenosine diphosphate) |
High energy molecule muscle cells store | Creatine phosphate |
Without oxygen | Anaerobic respiration |
With oxygen | Aerobic respiration |
The amount of oxygen needed in chemical reactions to convert lactic acid to glucose and to replenish the depleted stores of creatine phosphate store in muscle cells. | Oxygen debt |
Results when ATP is used during muscle contraction faster than it can be produced in the muscle cells. | Muscle fatigue |
2 types of muscle contractions | Isometric and isotonic |
Equal distance, tension increases | Isometric |
Equal tension, length changes | Isotonic |
Refers to constant tension produced by muscles of the body for long periods of time. | Muscle tone |
Contract quickly and fatigue quickly. Ex. white meat of chicken breasts | Fast-twitch fibers |
Contract more slowly and are more resistant to fatigue. Ex. dark meat of a duck's breast. | Slow-twitch fibers |
Muscle connects to bone | Tendons |
Most stationary end of the muscle | Origin |
The end of the muscle undergoing the greatest movement. | Insertion |
he portion of the muscle between the origin and the insertion | Belly |
Muscles that work together to accomplish specific movemens | Synergists |
Muscles that work in opposition to one another | Antagonists |
If one muscle plays the major role in accomplishing the desired movement it's the | Prime mover |
Muscles named according to their | Location, size, orientation of fibers, shape, origin, insertion, and function. |
Raises the eyebrows | Occipitofrontalis |
Closes the eyelids and causes “crows feet” wrinkles in the skin at the lateral corners of the eye. | Orbicularis oculi |
Puckers the lips | Orbicularis oris |
Flattens the cheeks. Trumpeter’s muscle. | Buccinator |
smilinh muscle | zygomaticus |