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86 Cards in this Set
- Front
- Back
A flexor is a skeletal muscle whose shortening moves attached bones |
Towards one another |
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Skeletal Muscles are usually attached to bones by |
Tendons |
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The origin is the skeletal muscle that usually attaches to the |
More stationary Bone |
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For antagonistic muscle groups to move a limb, flexor contraction occurs coincident with the |
The relaxation of the extensor |
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The function of transverse tubules is to |
Rapidly conduct action potentials to the interior of the muscle fibers |
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__________ is composed of multiple globular molecules polymerized to form long chains or filaments |
Actin |
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Most of the time, parrallel thick and thin filaments of the myofibrils are connected by |
Crossbridges |
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Striated muscles are so called because of the repeating patterns of Dark and light bands. One repeating unit of banding pattern is called |
Sarcomere |
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The I Band contains |
Thin filaments only |
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The H Zone contains |
Thick filaments only |
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The function of the titian protein is to |
Stabilize the position of the contractile filaments |
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When a skeletal muscle generates enough force during contraction to shorten, |
The Sarcomere and The I band band will shorten |
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Tension generated in the skeletal muscle fiber is directly proportional to the number |
Of High energy cross bridges formed |
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When skeletal muscle cells contracts and muscle shortens, |
some myosin heads are forming cross-bridges as others are releasing |
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In order for high force crossbrideges to form in skeletal muscle, calcium must bind to |
troponin, which moves tropomyosin |
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Each myosin head has a binding site for |
Actin and ATP |
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As ATP binds to the myosin head at the beginning of a muscle contraction cycle, the myosin immediately, |
Detaches from Actin |
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The molecular event that occurs immediately of the power stroke is |
release of ADP from myosin |
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Hydrolysis of ATP causes myosin to immediately |
Rotate into a position (cocked) to bind to Actin |
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Which of the following would cause a rossbridge ot transition from a high force state to a low force state |
Decrease in intracellular calcium |
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The Action potential traveling across the T-tubule is detected by |
Dihydropyridimine (DHP) receptor (L-type calcium channel) |
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the binding of acetylcholine to its receptor at the neuromuscular junction causes the opening of the |
CHANNEL FOR NA+ and K+ |
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The contraction cycle is triggered by the rise in_______ released by the sarcoplasmic reticulum |
K+ (potassium) |
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The relaxation of the skeletal muscle fiber relies on the activity of the_______ which decreases cytoplasmic calcium concentration. |
CA2+ATPase |
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The brief period of time between the beginning of the action potential in the muscle and the beginning of contraction is |
The latent period |
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__________is the backup energy that can be rapidly converted to Atp in the active skeletal muscle |
Phospocreatine |
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During heavy excercise, the Atp requirements of active muscle, are mostly likely to be met by the metabolism of |
Carbohydrates |
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Muscle fatigue arises primarily by the failure of |
Excitation-contraction coupling |
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The cause of skeletal muscle fatigue during extended submaximal exercise is due primarily to |
The depletion of glycogen stores. |
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Which of the following is a characteristic of Slow-twitch oxidative skeletal muscle |
long contraction duration and high capillary density. |
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the speed with which force is developed by skeletal muscle is determined by |
Myosin ATPAse Isoform |
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Within a single fiber, the tension developed during a twitch depends on the |
length of sarcomeres prior to contraction |
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When comparing complete tetanus with imcomplete (fused) tetnus, Which is true? |
complete tetanus involves development of maximum tension |
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A motor unit consists of |
one neuron and all the skeletal muscles it controls |
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Motor units that control skeletal muscles involved with fine motor movements (Eye muscles or the hands), have ______ muscle fibers than motors units that control more gross movements like the gasrtocnemius muscle of the lower leg. |
have fewer |
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Which of the following statements is not correct regarding their motor units and their activation. |
A weak contractile stimulus activates the fast twitch muscle. |
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Which fibers generate more force |
Fast-twitch |
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Which fibers fatigue sooner |
Fast-Twitch |
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The nervous system avoids fatigue during sub-maximal excercise by |
asynchronous movement |
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A contraction that generates enough force to move a load is known as_______Wherase one the generates force that equals the load is_________ |
Isotonic, isometric |
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Before the entire muscle can change lenght,the force generated by the muscle must stretch the |
series elastic elements |
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The lever system that characterizes the interaction between bones and muscle, the bones act as________ whereas he muscle acts as the _________ |
Lever, fulcrums |
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In order for the bicep muscle to shorten, the force applied to the muscle must be _________ the load at the hand |
greater than |
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Compared to the skeletal muscle the contraction of the smooth muscle cells is |
a slower to the response stimulus and sustained without fatigue. |
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Smooth muscle cells lack which protien |
Troponin only |
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Which of the following is not a property of single unit smooth muscles? |
Each cell functions independent of its neighbor |
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This protein is activated by Ca2+ calmodulin complex to phosphorylate the myosin light chain protein |
Myosin light chain kinase |
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The calcium release channel in the sarcoplasmic reticulm that is opened by increases in phospholipase C activity is |
Inositol triphosphate (IP3) receptor channel |
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A change in smooth muscle cell tension in the absence of change in the electrical potential of the cell is described as |
Pharmacomechanical coupling |
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Which of the following is not a correct comparision of cardiac myocytes to other cell muscle types |
like skeletal muscle, contraction of cardiac muscle cell contraction is under autonomic nervous control |
|
inward extensions of the muscle cell membrane |
T-tubules |
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Highly organized bundles of contractile proteins within a skeletal muscle |
Myofibril |
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A single muscle cell |
muscle fiber |
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A muscle cell membrane |
sarcolemma |
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A bundle of adjacent muscle cell |
fascicle |
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The structures that serve as the attachment sites for thin filaments and mark the boundaries for one sarcomere |
Z disk |
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the letter assigned to this structure stands for the german word middle, it is the attachement site for thick filaments |
M-Line |
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The lightest of color bands of the sarcomere, contains only thin filaments |
I band |
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The band with the most overlap between thick and thin filaments, which unevenly scatters light lead to its dark appearence |
A Band |
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What are the three types of skeletal muscle in the human body |
Skeletal, cardiac and smooth muscle. They generate force and generate motion |
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Groups of adjacent muscles bundled together are called_________ These bundles are surrounded by the proteins and elastin as well as________ that deliver nutrients to the muscle cell. |
Fiscicles,collagen,blood vessels |
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The thin filament of the myofibril is composed of_______ molecules whereas_________ is the protiens that make up the thin filaments |
Myosin, Actin |
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the T-tubular membrane contains_______ receptors that are _______ and therefore respond to action potentials. This receptor is mechanically linked to ________ adjacent receptors in the sarcoplasmic reticulum |
dihydropyridine (DHP), voltage sensing, Ryonandine or calcium release channel. |
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In order to contract muscles require energy in the form of______. The immediate backup energy is _________ which contains_________ |
ATP, phosphocreatine, creatine kinase |
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Calcium released by the sarcoplasmic reticulum binds to the _______ to move _______ in order to form A________ |
troponin C, tropomyosin, high-force crossbridge |
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The heavy chain of myosin contains two important regions: the first acts as______ to convert energy into movement whereas the second binds to________ |
ATPase, Actin |
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As muscle cell undergoes eccentric contraction, the sarcomere length will_______ as A band length ___________ |
increase, does not change |
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Fatigue that occurs in response to extended sub-maximal exertion is usually due to __________. where as fatigue due to short maximal exertion is due to________ |
gylcogen depletion, ion imbalance |
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The reductions in muscle force at lengths different from optimal are a result of |
a decrease in crossbridges |
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In fast twitch oxidative gylcolytic fibers, their rapid increases in force rely on_______ activity whereas rapid relaxation requires _______ activity |
Myosin ATPase, Ca2+ATPase |
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Asynchronous activation of muscle units are important because it functions to |
prevent muscle failure |
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Smooth muscle fibers can sustain a contraction without fatigue by allowing dephosphorylated myosin to remain attached to actin known as the |
Latch state |
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In comparison to skeletal muscle, smooth muscle cells function over a__________ range muscle lengths and exhibit a speed of contraction that is _________ than skeletal muscle |
wider, slower |
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store operated calcium channels open in response to |
depleted intracellular stores of calcium |
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The gap junctions in cardiac muscle, are part of specialized cell junctions that are localized in |
intercalated disks |
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In smooth muscle cells, Ca2+ binds to the _______ which activates the enzyme to_________ phosphorylate myosin and increase force. |
calmoldulin, myosin light kinase |
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A ______ and ________ are striated muscles.s |
skeletal and cardiac muscles. they are called striated because of their alternating dark and light bands. |
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a ________contraction describes the opening of stretch activated channels in smooth muscles in response to a distortion in smooth muscle that is commonly observed in______ |
smooth muscle |
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Endplate triggers action potentials transverse tubules convey potentials into interior of the cell Acetylocholine bind to the receptors on motor end plates ca2+ is released from the endoplasmic reticulum. |
3, 1,2,4 |
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After death when the metabolism stops, which step of the contractile muscle do the muscles remain |
Rigor state |
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The factors that determine the twitch in various types of fibers is speed of the |
removal of Ca2+ ions from the sarcoplasm |
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skeletal muscles with the greatest endurance rely on |
Oxidative phosporylation |
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the force generated by a single muscle fiber cell can be increased by |
increasing frequency of action potentials |
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Put these myofibrils in order they would be recruited through the body as they move from a weak to strong stimulus |
3,2,1 |
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An important difference between single unit and multi-unit smooth muscle is |
numerous gap junctions in single unit smooth muscle, which allow many cells to work together as a sheet. |
|
Relative to skeletal muscle, smooth muscle |
uses less energy to generate a given amount of force can sustain contractile energy without fatiguing and uses calcium from the intracellular membrane and extracellular space. |