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Anatomy
Question | Answer |
---|---|
contractility | shorten with force |
Excitability | capacity to respond to a stimulus |
Extensibility | to be stretched |
Elasticity | ability to recoil their original length |
Muscles | help to produce heat essential |
Epimysium | connective tissue sheath |
Fascia | connective tissue |
Surrounds and separates muscles | Epimysium |
a muscle composed of numerous bundles | Fasciculi |
surrounded by loose connective tissue | Perimysium |
fasciculi composed of single muscle cells | fibers |
myofilbrils | threadlike structure |
2 kinds of protein fibers | actin and myosin myofilaments |
actin | thin 2 minute strands of pearls twisted together |
myosin | thick bundles of minute golf clubs |
actin and myosin | form units called sarcomeres |
Sarcomeres | joined end to end to form myofibril |
each sarcomeres | extends from one Zline to another Zline |
Z line | attachment site for actin |
light area | I band |
I band | consist of actin |
A band | extends length of myosin |
Center | Light area is the H zone |
H zone | only myosin |
myosin | in the center is also a dark staining band is M line |
outside cell membranes | positively charged |
inside cell membranes | negatively charged |
resting membrane potential | charge difference |
action potential | the reversal back for the charge |
motor neurons | nerve cells carry action to muscle fibers |
axons | enter the muscles and branch |
neuromuscular junction | branch that connects to the muscle |
synapse | center of the cell |
motor unit | single motor and skeletal muscle fibers |
Enlarged nerve terminal | presynaptic terminal |
space between presynaptic terminal and muscle cell | synaptic cleft |
muscle fiber | postsynaptic terminal |
Each presynaptic terminal | synaptic vessels |
synaptic vessels secrete neurotransmitter | acetylcholine |
sliding actin past myosin | sliding filament mechanism |
H and I bands | shorten |
A bands | dont change in length |
muscle twitch | contraction of an entire muscle |
stimulus reaches a level | threshold |
muscle fiber contact maximally | all or none response |
all or none response | phenomenon |
lag phase | time between application of a stimulus to a motor neuron and beginning |
time of contraction | contraction phase |
time during the muscle relaxes | relaxation phase |
tetany | where the muscle remains contracted without relaxing |
increase in number of motor units being activated | recruitment |
needed for energy for muscle contraction | ATP |
produced in the mitochondria | ATP |
is short lived and unstable | ATP |
anaerobic respiration | without oxygen |
aerobic respiration | with oxygen |
oxygen debt | the amount of oxygen needed in chemical reactions |
isometric | length doesnt change |
isotonic | length does change |
muscle tone | tension produced by muscles of the body |
fast twitch fibers | contract quickly and fatigue quickly |
slow twitch fibers | contract more slowly and are more resistant to fatigue |
origin | most stationary end of the muscle |
insertion | end of the muscle undergoing the greatest |
between the origin and the insertion | Belly |
some muscles | have multiple origins or head |
muscles that work together to accomplish specific movements | synergists |
muscles that work in opppsition to one another | antagonists |
prime mover | group of synergists |
raises the eyebrows | occipitofrontalis |
puckers the lips | orbbicularis |
frowning | depressor anguli oris |
sneering | levator labii superioris |
smiling muscle | zygomaticus |
intrinsic tongue muscles | change the shape of tongue |