Term
| How are skeletal muscle fibers formed? |
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Definition
| By the fussion of multiple myoblasts (mesodermal cells). |
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Term
| What are the 3 levels of muscle organization? |
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Definition
| Muscle, Fascicles, & Fibers |
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Term
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Definition
| A dense connective tissue capsule that surrounds muscles. |
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Term
|
Definition
| Connective tissue capsule surrounding the Fascicles in a muscle. |
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Term
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Definition
| Capsule that surrounds Fibers in a muscle. |
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Term
| What do all 3 "mysiums" do at the end of a muscle? |
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Definition
| Merge at the end to form tendons that attach to bones. |
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Term
| What does T-Tubules stand for? |
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Definition
|
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Term
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Definition
| Tubular extensions of cell membrane into a cell. |
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Term
| What are T-Tubules used for? |
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Definition
| To transmit the Action Potential through the cell, and to allow the entire muscle fiber to contract simulataneously. |
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Term
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Definition
| Bundles of protein filaments that are responsible for muscle contraction. |
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Term
| What are the 2 types of Filaments in Myofibrils? |
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Definition
|
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Term
| What are Thin Filaments made of? |
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Definition
|
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Term
| What are the Thick Filaments made of? |
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Definition
|
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Term
| What is the Sarcoplasmic Reticulumn? |
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Definition
| A membrane bag that surrounds each myofibril. |
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Term
| What is the Sarcoplasmic Reticulumn responsile for? |
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Definition
| Releasing calcium in response to Action Potential in T-Tubules. |
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Term
| What is the Sarcoplasmic Reticulumn responsile for? |
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Definition
| Releasing calcium in response to Action Potential in T-Tubules. |
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Term
| What happens once Calcium enters the Myofibril? |
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Definition
| Muscle contractions initiate |
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Term
| What are Myofibrils made up of? |
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Definition
| Sarcomeres that are stacked end to end. |
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Term
|
Definition
| The basic contractile unit of muscles. |
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Term
| What 5 things are Sarcomeres composed of? |
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Definition
| Thin Filaments, Thick Filaments, Z-Line, M-Line, & Zone of Overlap |
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Term
| What is the M-Line, and what does it do? |
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Definition
| Midline of sarcomere and it connects adjacent thick filaments. |
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Term
| What is the Z-Line, and what does it do? |
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Definition
| Forms the end of sarcomeres and it connects adjacent thin filaments. |
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Term
| What is the Zone of Overlap? |
|
Definition
| Where Thin & Thick Filaments meet. (dark area on micrograph) |
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Term
| What are the Myosin Molecules on Thick Filamnts responsible for? |
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Definition
| the head latches onto the thin filament and bends at the hinge to slide the thing filament towards the M-Line. |
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Term
| What are Thin & Thick Filaments linked by? |
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Definition
|
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Term
| What binds to the Troponin Molecule? |
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Definition
| Ca2 that is released by the Sarcoplasmic Reticulumn. |
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Term
| What happens when the Active Site becomes exposed? |
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Definition
| Myosin heads on the adjacent Thick Filaments bind to them. |
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|
Term
| What is the Motor End Plate? |
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Definition
| Place where tips of a motor neuron axon contact a muscle cell to stimulate muscle contraction. |
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Term
| What is the Neuromuscular junction? |
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Definition
| the actual contact between the axon tips and the muscle cell sarcolemma. |
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Term
|
Definition
| A fixed muscular contraction after death. |
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Term
| What causes Rigor Mortis? |
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Definition
| When calcium builds up in the cytoplasm because it is no longer actively pumped back into sarcoplamic reticulum. |
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Term
| What does Muscle Tension depend on? |
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Definition
| the frequency of neural stimulation and, the fibers resting length at the time of stimulation. (the amount of overlap between thin & thick filaments) |
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Term
| What happens when the Zone of Overlap is too small? |
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Definition
| Tension is lowered because not all myosin heads can attach to the thin filaments |
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Term
| What happens when the Zone of Overlap is too big? |
|
Definition
| creates resistance to filament sliding |
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Term
| What is Muscle Recruitment? |
|
Definition
| activation and summation of multiple motor units |
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Term
| What are the 3 types of muscle contractions? |
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Definition
| Concentric, Eccentric, & Isometric |
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Term
| What is a Concentric Contraction? |
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Definition
| muscle tension > resistance, causing muscle to shorten |
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Term
| What is an Eccentric Contraction? |
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Definition
| muscle tension < resistance, causing muscle to lengthen |
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Term
| What is an Isometric Contraction? |
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Definition
| muscle tension = resistance, causing muscle to stay the same length |
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Term
|
Definition
|
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Term
|
Definition
| the energy molecule necessary for contraction |
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|
Term
|
Definition
| When muscles can no longer perform a required activity |
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|
Term
| What are the 3 characteristics of muscle fatigue? |
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Definition
Exhaustion of metabolic reserves,
High acidity from presence of lactic acid, and
Damage to cell membrane & sarcoplasmic reticulum |
|
|
Term
| What 2 things does the liver do to replenish energy precursors? |
|
Definition
| converts lactic acid to pyruvic acid for later conversion to ATP, and releases glucose to recharge muscle glycogen reserves, also for future ATP production |
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Term
| What are the 3 types of Skeletal muscle fibers? |
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Definition
| Fast, Slow, and Intermediate Fibers |
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Term
| What color are pale muscles composed mostly of fast fibers (e.g., chicken breast) |
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Definition
|
|
Term
| What color are dark muscles composed of mostly slow fibers (e.g., chicken legs)? |
|
Definition
|
|
Term
| What color are human muscles? |
|
Definition
| pink muscle composed of a mixture of fiber types |
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Term
| What is Muscle Hypertrophy |
|
Definition
| growth from heavy training |
|
|
Term
| what does muscle hypertrophy involve? |
|
Definition
increased diameter of muscle fibers,
increased number of myofibrils,
increased number of mitochondria & glycogen reserves, and increased power |
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Term
|
Definition
| muscle shrinkage due to lack of activity |
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|
Term
| What does muscle atrophy involve? |
|
Definition
|
|
Term
| What does aerobic endurance involve? |
|
Definition
| prolonged, aerobic activities (e.g., aerobic exercise) |
|
|
Term
| What does aerobic endurance emphasize? |
|
Definition
|
|
Term
| How is aerobic endurance improved? |
|
Definition
| By building up cardiovascular fitness through repetitive training |
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