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Chapter 6- Muscles
Question | Answer |
---|---|
ability to shorten with force | contractility |
capacity to respond to a stimulus | excitability |
ability to be stretched | extensibility |
ability to recoil to original length | elasticity |
muscles produce what? | heat |
connective tissue sheath called... | epimysium |
connective tissue located outside epimysium | Fascia |
surrounded by loose connective tissue called... | perimysium |
single muscle cells | fibers |
cytoplasm each fiber filled with | myofibrils |
myofibrils consist of 2 protein fibers | actin myofilaments & myosin myofilaments |
highly ordered units called | sacromeres |
sacromere extends from | one z line to another z line |
Each side of the z line light area called... | an I band |
I band consists of- | actin |
The A band extends the length of the | myosin |
charge difference across the membrane | resting membrane potential |
brief reversal back of charge is called... | action potential |
nerve cells that carry action potentials to skeletal muscle fibers | motor neurons |
a single motor neuron and all the skeletal muscle fibers it innervates are called... | motor unit |
secrete a neurotransmitter called... | acetylocholine |
contraction of entire muscle | muscle twitch |
point at which muscle fiber ill contract maximally | threshold |
time between application of a stimulus to a motor neuron and the beginning of a contraction | lag phase |
contraction phase | time of the contraction |
relaxation phase | time during which muscle relaxes |
tetany | where muscle remains contacted without relaxing |
increase in number of motor units being activated | recruitment |
atp | adenosine triphosphate |
atp | needed for energy for muscle contraction |
produced in the mitochondria | atp |
short-lived, unstable | atp |
without oxygen | anaerobic respirtation |
with oxygen | aerobic respiration |
amount of oxygen needed in chemical reactions to convert lactic acid to glucose to replenish | oxygen debt |
faster than it can be produced | muscle fatigue |
muscle contractions | two types |
isometric | equal distance |
equal tension | isotonic |
keeps head and back straight | muscle tone |
contract quickly fatigue quickly | fast-twitch fibers |
white meat is an example of- | fast-twitch fibers |
dark meat is an example of- | slow-twitch fibers |
contract more slowly and resist fatigue | slow-twitch fibers |
points of attachment of each muscle | origin and insertion |
another name for origin | head |
most stationary end of the muscle | origin |
undergoes greatest movement | insertion |
end of the muscle | insertion |
belly | between the origin and insertion |
t/f some multiples have multiple origins | true |
muscles that work together | synergists |
muscles that work in opposition | antagonists |
among a group of synergists | prime mover |
plays major role in accomplishing the desired movement | prime mover |
muscles have names that are_____________ | descriptive |
some are named according to_____________ | shape, size, origin insertion, orientation of fibers, and function |
raise the eyebrows | occipitofrontalis |
closes the eyelids | orbicularis oculi |
buccinator | flattens the cheeks |
puckers the lips | orbicularis oris |
oribicularis oris and buccinator are ___________ muscles | kissing muscles |
smiling muscles | zygomaticus |
sneering | levator labii superioris |
frowning | depressor anguli oris |
chewing | mastication |
________ pair of mastication muscles | 4 |
2 pair of | pterygoids, temporalis, and masseter |
tongue muscles | two types |
instrinsic tongue muscles | change the shape of the tongue |
extrinsic tongue muscles | move the tongue |
neck muscle | sternocleidomastoid |
sheetlike muscle that covers the anterolateral neck | platysma |
group of muscles on each side of the back | erector spinae |
responsible for keeping the back straight and erect | erector spinae |
muscles that move the thorax | thoracic muscles |
most involved in breathing | external intercostals and internal instercostals |
external intercostals | elevate ribs during inspiration |
internal intercostals | contract during forced expiration |
accomplishes quiet breathing | diaphragm |