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three types of muscle | Smooth, Cardiac and Skeletal |
skeletal muscle | voluntary attached to bones, skin of face |
cardiac muscle | walls of the heart involuntary |
smooth muscle | found in walls of internal organs such as those of digestive tract involuntary |
skeletal muscle 2 | composed of skeletal muscle tissue nervous tissue blood and connective tissue |
connective tissue coverings | fascia, tendons, aponeuroses |
Aponeuroses | broad sheet in skull connecting muscle to muscle also in stomach |
Muscle coverings | Epimysium perimysium and endomysium |
Epimysium | surrounds whole muscle |
perimysium | surrounds fascicles within a muscle |
endomysium | surrounds muscle fibers cells with a fascicle |
fiber muscle cell | mutinucleated sarcolmma sarcoplasm many myofibrils myofibrils consist of thin actin and thick myosin sarcomeres sarcoplasmic reticulum transverse t tubule triad and SR cisternae |
sarcomeres | contain i band, a band, h zone, z line or z disc, m line |
I band | light band composed of the thin actin filamets |
A band | dark band composed of thick myosin filaments |
z line | anchors filaments in place |
h zone | center of a band compose of thick myosin filaments |
M line | anchors thick filaments center of A band |
Thick filaments | composed of myosin protein heads form cross bridges |
thin filaments | composed of actin protein associated with troponin and tropomyosin which prevent cross bridge formation when muscle is not contracting |
neuromuscular junction | a type of synapse also called a myoneural junction site where an axon of motor neuror and skeletal muscle fiber interact |
Acetylcholine ach | is the neurotransmitter nerve impulse causes release of ach from synaptic vesicles |
Myasthenia gravis | is an auto immune disorder antibiotics attack acetylcholine receptors on skeletal muscle fibers |
Excitation contraction coupling | connection between muscle fiber stimulation and muscle contraction |
ATP | helps muscles relax |
Mystin head | helps build muscle up for contraction |
Acetylcholiesterase | enzyme rapidly decomposed ach remaining in the synapse muscle impulse stop when ach is decompsed |
calcium pump | moves ca+2 back into sacoplasmic reticulum |
Troponin tropomyosin complex | again covers binding sites on actin |
Energy sources for contracting | ATP reserves small amount, creatine phospate initial source of energy to regenerate ATP from ADP and P, cellular respiration |
Cellular respiration | anaerobic phrase: glycolysis occurs in cytoplasm produces little ATP Aerobic phrase: citric acid cycle and electron transport system occurs i nthe mitochondria produces ATP myoglobin stores extra oxygen in muscles |
anaerobic threshold | shift in metabolism from aerobic to anaerobic during strenuous muscle activity |
oxygen debt | amount of oxygen needed by liver cells to convert the accumulated lactic acid to glucose and to restore muscle ATP |
Muscle fatigue | unable to contract muscle |
muscle cramp | sustained involuntary muscle contraction may be cause by changes in electrolyte concentration in extracellular fluids in the area |
Heat production | by product of cellular respiration in active cells muscle cells are major source of body heat |
muscular response | muscle contraction can be observed by removing a single skeletal muscle fiber and connecting it to a device that senses and records changes in the overall length of the muscle fiber |
threshold stimulus | minimum strength of stimulation of a muscle fiber required to caused contraction |
Twitch | contractile response of a single muscle fiber to a single impulse |
summation | process by which the force of individual muscle fiber twitches combine |
motor unit | a motor neuron all of the muscle fibers it controls |
Recruitment | increase in the number of motor units activated to produce more force |
Isotonic | muscle contracts and changes length equal force |
Isometric | muscle contracts but does not change length change in force |
Slow twitch fiber | always oxidative resistant to fatigue |
fast twitch fatigue | intermediate twitch fibers |
fast twitch glycolytic fibers | anaerobic respiration white fibers poorer blood supply |
Hypertrophy | enlargement of skeletal muscle that is exercised |
Atrophy | decrease in size and strength of skeletal muscle that is unused |
Smooth muscle | shorter single centrally located nucleus elongated with tapering ends |
Multi unit smooth muscle | cells are less organized |
visceral smooth muscle | single unit smooth muscle cells respond as a unit |
Different from skeletal muscle contraction in these ways | smooth muscle lacks troponin uses calmodulin instead |
Cardiac muscle | striated muscle cells muscle fibers joined together by intercalated disks |
Skeletal muscle actions | generate a great variety of body movements |
4 basic component of levers | rigid bar or rod bones, fulcrum or pivot on which bar moves, object moved against resistance and force that supplies energy for movement |
Origin | less movable end |
insertion | more moveable end when muscle contracts insertion is pulled toward origin |
Agonist | muscle that causes an action |
prime mover | agonist primarily responsible for movement in some cases the terms agonist and prime mover are used interchargebly |
synergists | muscle that assist agonist/prime mover |
antagonist | muscles whose contraction causes movement in the opposite direction of the prime mover |