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Stack #114380
phys ch. 10 pt. 1skeletal muscle
Question | Answer |
---|---|
Any movement requires which tissue? This is one function of this tissue. | Muscle. |
Why is muscle a significant source of body heat production? This is another function of muscle tissue. | Metabolism produces heat, and there is a large amount of muscle tissue for metabolism to occur in. |
What is defined as "supporting the body against gravity?" This is another function of muscle tissue. | Posture |
What organs do muscle primarily support? (Another function of muscle tissue.) | The abdominal organs. |
A skeletal muscle cell is also called what? | A muscle fiber. |
Why is it called skeletal muscle? | It is attached to the skeleton. |
What is the plasma membrane of the muscle cell called? | The sarcolemma. |
What are t-tubules? | Tubules that extend into the cell, they carry the signal to contract to the inside of the cell. |
What is the cytoplasm of the muscle cell and what type of energy-storage granules are contained therein? | The sarcoplasm contains glycogen granules. |
What cell is multinucleated? | The muscle cell. |
What is the endoplasmic reticulum of the muscle cell? | The sarcoplasmic reticulum. |
What are the energy organelles that produce ATP? | mitochondria. |
What are the contractile proteins found within muscle cells known as? | myofibrils. |
What are the two types of filaments found within the myofibril, and what are they made of? | Thick filaments are made of myosin, and thin filaments are made of actin. |
What is the arrangement of contractile proteins, subunits of the myofibril, called? | Sarcomeres. |
What produces the banded appearance of skeletal muscle? | The arrangement of proteins in the sarcomere. |
What is the A band also known as? | The dark band. |
What are the three main components of the A band? | The M line, the H zone, and the zone of overlap. |
What is the center of the dark band called? | The M line. |
What zone lies on each side of the M line and contains only thick filaments? | The H zone. |
What zone within the A (dark) line contains both thick and thin filaments? | The zone of overlap. |
What is the I band also known as? | The light band. |
What determined the beginning and end of one I band? | The band runs from one A band to the next A band. |
What type of filaments are found in the I band? | Thin filaments only. |
What line do the thin filaments attach to? | The Z line. |
What is the thick filaments main protein? | Myosin. |
What three components make up the structure of the thick filament? | The tail, head, and hinge area. |
What part of the thick filaments structure is long and attached to other myosin molecules? | The tail. |
What enzyme does the thick filaments head ac as? | ATPase. |
Which area of the thick filament allows the head to bend? | The hinge area. |
When the muscle cell is relaxed, which direction do the heads point? | Away from the M line. |
What is the elastic protein that extends from the Z-line to the thick filament? | Titin. |
What is the main protein of the thin filament? | Actin. |
What is the thin filaments round, globular protein called? | G-actin. (Globulin) |
What is a long filament of G-actin called? | F-actin. (Filamentus) |
What protein covers the active site of G-actin and what is the ratio of that protein to G-actin? | There is 1 tropomysin protein molecule for every 7 G-actin protein molecules. |
3 protein subunits make up which component of the thin filament? | Troponin. |
What do these three subunits each attach to? | G-actin, tropomysin, and calcium. |
Which line are the thin filaments attached to? | The Z line. |
What theory attempts to explain muscle contraction? | Sliding filament theory. (apparently pretty much a sure thing.) |
During muscle contraction, whic filaments slide to the center of the sarcomere? | The thin filaments. |
Do the thin and thick filaments change length during muscle contraction? | No, they slide. |
What happens to the sarcomere as a whole during muscle contraction? | It gets shorter. |
What is the junction between a neuron and muscle cells called? | A neuromuscular junction. |
What two parts make up the motor unit? | One motor neuron and all the muscle cells it ennervates. |
What is the neurotransmitter for skeletal muscle contraction that is released from the motor neuron? | Acetylcholine. (ACh) |
What is the end branch of the motor neuron? | The synaptic terminal. (Where the ACh is) |
What is the area of the sarcolemma next to the motor neuron? | The motor end plate. |
When an action potential reaches the synaptic terminal, which neurotransmitter is released? | ACh is released from the synaptic terminal. |
ACh binds to receptors located where? | On the motor end plate. |
After Ach binds to the motor end plate, where is action potential generated? | In the sarcolemma. |
Action potential spreads from the sarcolemma to where? | The T tubules. |
After the action potential spreads to the T tubules, what organelle is Ca++ released from? | The sarcoplasmic reticulum. |
Ca++, after release from the sarcoplasmic reticulum, binds to a protein subunit. Which potein is the subunit part of? | Troponin. |
What protein is shifted after Ca++ binds to troponin? | Tropomysin. |
What happens when tropomysin is shifted that allows muscle contraction? | Active sites on the G-actins are uncovered. |
When active istes on G-actin are uncovered, what cycle begins? | The contraction cycle. |
What is the myosin head binds to actin? | A cross-bridge formation. |
What is the power stroke? | Myosin moves actin towards the center of the sarcomere using stored energy. |
How does cross-bridge dissociation occur? | ATP binds to myosin head and breaks bond between thick and thin filaments. |
What is myosin reactivation? | ATP energy is stored in the myosin head. |
What is the enzyme that breaks down acetylcholine? | Acetylcholinesterase. |
What does calcium ATPase do? | Moves calcium out of the sarcoplasm. |
Where does calcium ATPase move sarcoplasmic calcium to? | Back into the sarcoplasmic reticulum. |
What is the kind of contraction that results from a single nerve impulse? | Simple twitch. |
What type of contraction is it when a stimulation directly follows complete relaxation? | treppe. |
What is several twitches that increases strength of contraction over time? | wave summation. |
What type of contraction is a rapid sequence of stimuli that produces a sustained contraction? | tetanus. |
What is the name of the small amount of contraction that is always present that stabilizes the body? | muscle tone. |
What are the three types of fibers? | fast, slow, and intermediate. |
What types of muscle fibers contract quickly and fatigue quickly? | Fast fibers. |
What types of muscle filers contract slowly and fatigue slowly? | Slow fibers. |
What types of muscle fibers are between slow and fast muscle fibers? | Intermediate fibers. |
Which muscles have all three types of muscle fibers? | All muscles have all three types of fibers, in varying ratios. |
What type of fibers do the muscles that control posture have in abundance? | Slow fibers. |
In muscle, what is the phosphate source for ATP synthesis? | Creatinine phosphate. |
ADP + CP - -> | ATP + C |
What is the primary energy source for resting muscle? | Fatty acids. |
Where does contracting muscle get its energy? | From glucose from blood and it breaks down glycogen into glucose. |
What are the steps of glycogen metabolism? | liver glycogen - glycogen - glucose - blood - muscle cell |
If the muscle uses glucose for energy production aerobically, what is produced? | ATP and CO2 |
If the muscle cell produces energy anerobically, what is produced? | Energy and actic acid. |
What is the path of muscle fatigue? | Increase in lactic acid - decrease in pH - decrease in ATP synthesis - decreased contraction - muscle fatigue |
What is the path of oxygen debt? | Exercise hard - continue breathing hard after exercise - use 02 to oxidize lactic acid to regenerate ATP and phosphocreatinine. |
What are the steps of the Cori cycle | Lactic acid from skeletal muscle released into blood - liver converts it to glucose - released into blood - skeletal muscle uses glucose to make glycogen - glycolisis generates lactic acid |