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| A rested skeletal muscle would probably have enough stored ATP for contractions lasting about ____. | 5 seconds |
| If skeletal muscle contraction continues for about 15 seconds, which 2 ATP sources would be expected to supply the energy for contraction? | Stored ATP and the phosphagen system |
| The special molecule in skeletal muscle that can take a phosphate from ATP while the muscle is resting and attach the phosphate back to ADP while the muscle is contracting is ____. | Creatine (which becomes creatine phosphate while the phosphate group is attached). |
| When ATP is broken down, the products are ____ and energy. | ADP |
| The enzyme that phosphorylates creatine is ___. | Creatine kinase |
| The series of reactions known as anaerobic cellular respiration occurs in the ____ of the cell. | Cytoplasm |
| Another term that describes the reactions of anaerobic cellular respiration is ___. | Glycolysis |
| The compound that enters the glycolysis reactions is ___. | Glucose |
| As glycolysis proceeds, the cell gains ____ ATPs. | 2 |
| The end product of glycolysis is ___. | 2 molecules of pyruvic acid (from one molecule of glucose) |
| If a process is anaerobic, that means it requires no ___. | Oxygen |
| In skeletal muscle activity lasting about 45 seconds, what 3 sources of ATP would probably be required? | Stored ATP, phosphagen system, and glycolysis (anaerobic cellular respiration) |
| Pyruvic acid from glycolysis is expected to go straight into the ____ and enter into the series of reactions called ___. | Mitochondria / aerobic cellular respiration |
| If pyruvic acid accumulates in the cell, it is converted to ____. | Lactic acid |
| Lactic acid accumulation in muscle cells results in the ____ sensation we feel as a muscle tires. | Burning |
| Aerobic processes require lots of ___. | Oxygen |
| Aerobic cellular respiration reactions occur in the ___. | Mitochondria |
| In exercise lasting more than 10 minutes, approximately ____ of the energy is produced aerobically. | 90% |
| The most effecient way to produce large amounts of ATP is ___. | Aerobic cellular respiration |
| Aerobic cellular respiration includes 2 series of chemical reactions: | Kreb's cycle and electron transport chain |
| True or false--a muscle in a state of central fatigue cannot possibly continue to contract. | False--feels tired but can continue if we force it |
| We continue heavy breathing for a time after muscle activity has ended--what is happening that requires all the extra oxygen? | Mainly converting lactic acid to glucose or glycogen, synthesizing creatine phosphate, and storing oxygen in myoglobin |
| A single skeletal muscle contraction in response to a single nerve impulse is called a ___ contraction. | Twitch |
| Twitch contractions in skeletal muscle are measured in what unit of time? | Milliseconds (1/1000s of a second) |
| Contraction and relaxation periods of twitch contractions last how long? | Usually 10 - 100 milliseconds |
| The period of lost excitability immediately following a stimulus in muscle is called the ____ period. | Refractory |
| The period IMMEDIATELY following a stimulus before muscle contraction begins is the ___ period. | Latent |
| What is the all-or-none principle in muscle? | If a muscle fiber contracts at all, it contracts to the fullest extent possible. |
| Contraction of entire muscles can vary in strength. This is due to variations in what 2 factors? | Timing of stimuli and number of motor units activated. |
| Stimuli arriving at different time in skeletal muscle can cause successively stronger contractions. This is called _____ summation. | Wave or temporal |
| Muscle contractions added together to produce a sustained contraction with some relaxation between is called ____ ____. | Incomplete (unfused) tetanus |
| Muscle contractions added together with no relaxation is ____ ____. | Complete (fused) tetanus |
| Ability to adjust the number of motor units firing at once is called ___. | Recruitment |
| Recruitment gives us the ability to do what 3 things? | Contractions of varying strength, sustained contractions with less fatigue, smooth movements |
| List some characteristics of slow oxidative muscle fibers. | Small diameter, less powerful, slow to get started, ATP produced mainly by aerobic cellular respiration, and then broken down slowly, red color due to myoglobin & lots of capillaries, lots of mitochondria. |
| List some characteristics of fast glycolytic muscle fibers. | Large diameter, powerful, quick starters but also quick to fatigue, pale color, fewer mitochondria & capillaries, ATP mainly by glycolysis. |
| List some characteristics of fast glycolytic-oxidative muscle fibers. | Intermediate in some ways--red, lots of ATP by both glycolysis & aerobic cellular respiration, break down ATP faster than SO fibers |
| Muscle fibers that are striated & involuntary. | Cardiac |
| Muscle fibers with one nucleus per fiber, fibers branch and interconnect, intercalated discs. | Cardiac |
| Great degree of autorhythmicity due to specialized conduction tissue. | Cardiac |
| Why does cardiac muscle need a longer-lasting basic contraction than skeletal? | Must stay contracted long enough to pump blood. |
| Why is heart muscle designed with a prolonged refractory period? | Must not undergo tetanus--if it did, there would be no way for the heart to fill with blood. |
| Muscle tissue with spindle-shaped fibers and no striations. | Smooth |
| A muscle fiber with dense bodies, calmodulin, and myosin light chain kinase must be which type? | Smooth |
| Smooth muscle tissue with nerve connections to only some of the fibers is classified as _____ smooth muscle. | Visceral or single-unit |
| Smooth muscle tissue with a nerve connection to each and every fiber is classified as ____ smooth muscle. | Multiunit |
| Smooth muscle tissue of the arrector pili muscles and large arteries would be which type of smooth muscle? | Multiunit |
| Smooth muscle tissue of the smaller blood vessels and in the wall of the stomach would be which type of smooth muscle? | Visceral (single-unit) |
| Muscle tissue with greatest powers of regeneration. | Smooth |
| Muscle tissue with poor regeneration. | Skeletal & cardiac |
| Pericytes may develop into this type of msucle fiber. | Smooth |
| Satellite cells may develop into this type of muscle fiber. | Skeletal |
