Term
| Term: Measure changes in muscle length using lever system |
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Definition
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Term
| Term: Lag before muscle lifts load |
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Definition
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Term
| Term: Action potential -> Latent period -> Muscle shortens varying amounts |
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Definition
| Isotonic twitch contraction |
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Term
| Term: When stimulus reaches muscle with load, produces isometric first as muscle struggles to lift load but no muscle shortening |
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Definition
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Term
| What happens when the amount of force = afterload? |
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Definition
| Muscle begins to shorten and lift load (isotonic portion) |
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Term
| How can a contraction be entirely isotonic? |
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Definition
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Term
| What happens with a heavier afterload? |
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Definition
| Isometric portion lasts longer, and it takes longer to increase force to lift load |
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Term
| How can a contraction be entirely isometric? |
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Definition
| Only if afterload is more than what the muscle can lift |
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Term
| The lighter the load, the...? |
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Definition
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Term
| The heavier the load, the...? |
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Definition
| Less the muscle can shorten |
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Term
| Term: Rate of doing work/force times velocity |
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Definition
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Term
| What happens at the max force a muscle can obtain? |
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Definition
| Power output = 0 because isometric muscle doesn't shorten |
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Term
| What happens at Vmax (no load)? |
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Definition
| Shortening most rapid but no force is exerted so power output = 0 |
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Term
| When does power output hit max? |
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Definition
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Term
| Muscles are surrounded by what? |
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Definition
| Electrically excitable plasma membrane |
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Term
| Surface membrane of muscle can be excited to do what? |
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Definition
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Term
| What is AP caused in muscle plasma membrane? |
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Definition
| Time and voltage-dependent changes in membrane permeability to Na+ and K+ |
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Term
| The diffusion problem of an AP to get to the inner-workings of a muscle is solved by what? |
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Definition
| Transverse tubular system |
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Term
| Term: Extensions of muscle surface membrane |
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Definition
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Term
| At rest, where is calcium highly concentrated? |
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Definition
| Sac-like areas of Sarcoplasmic Reticulum (Terminal cisternae) |
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Term
| If a person has diabetes melitus, what is different about their urine? |
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Definition
| They have glucose in their urine |
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Term
| What happens to the ACh released by an AP? |
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Definition
| Binds to receptors on motor end plate of muscle membrane, opens channels, and allows Na+ and K+ to flow, which depolarizes end plate membrane |
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Term
| Term: Skeletal/cardiac muscle responds to one stimulus with single AP and response |
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Definition
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Term
| What limits the amount of force developed by a twitch? |
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Definition
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Term
| Term: Force produced by 2nd stimulus can add to force left from first |
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Definition
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Term
| Term: Sustained contraction with much more force than twitch |
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Definition
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Term
| Term: Stimuli spaced relatively far apart, force rising/falling between stimuli |
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Definition
| Partial (unfused) tetanus |
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Term
| Term: Stimuli close, developed force steady |
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Definition
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Term
| Term: Lowest frequency to produce fused tetanus |
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Definition
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Term
| What is the tetonic fusion frequency? |
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Definition
| 20-40 times per second for skeletal muscle |
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Term
| What are the most useful contractions? |
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Definition
| Mix of twitches and partly fused tetanic contractions |
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Term
| Which muscle is the twitch-only type? |
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Definition
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Term
| How can drugs be a major factor in the amount of calcium available? |
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Definition
Some drugs increase overall internal supply of calcium, more released from S.R. with each beat
Some are calcium blockers and can reduce the strength of contractions and epinephrine which increases the strength of contraction by permitting an accumulation of internal calcium |
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Term
| What does the tension produced by whole muscle contraction depend on? |
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Definition
| The amount of force developed by each fiber and the number of active fibers in muscle |
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Term
| Muscles that produce delicate movements have...? |
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Definition
| A small number of fibers per unit |
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Term
| Muscles that are large and produce less delicate movements have...? |
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Definition
| A large number of fibers per unit |
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Term
| Strength and susceptibility to fatigue of a muscle can be changed by...? |
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Definition
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Term
| How does long-duration/low-intensity "aerobic" exercise decrease muscle fatigue? |
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Definition
| Increases fibers capacity for ATP production by increasing the number of mitochondria and blood vessels in muscle, resulting in greater endurance |
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Term
| How does short-duration/high-intensity "anaerobic" exercise increase muscle fatigue? |
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Definition
| Increases fiber diameter due to increased synthesis of actin/myosin, resulting in increased strength. Very powerful but fatigue rapidly |
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Term
| Term: Decline in muscle force as a result of previous contractions |
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Definition
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Term
| The onset of fatigue depends on what three issues? |
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Definition
Type of fiber
Intensity and duration of contractions
Level of fitness |
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Term
| What are the two major factors in fatigue of skeletal muscle? |
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Definition
Conduction failure
Lactic acid buildup |
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Term
| Term: Muscle AP fails to be conducted in T-tubules, stops calcium release from terminal cisternae |
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Definition
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Term
| Term: High proton concentration alters calcium release and function of calcium-ATPase pumps of Sarcoplasmic Reticulum |
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Definition
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Term
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Definition
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Term
| Term: Will to win between brain and skeletal muscle |
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Definition
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Term
| True/False: CNS and PNS can act independently |
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Definition
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Term
| Skeletal muscle depends on the __ __ for control |
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Definition
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Term
| True/False: Both afferent and efferent neurons control skeletal muscle |
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Definition
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Term
| How do sensory neurons form muscle spindles? |
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Definition
| They connect with intrafusal muscle fibers deep inside |
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Term
| Term: Length detectors that act as strength receptors and increase the rate of APs when intrafusal fibers stretch |
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Definition
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Term
| Term: Tension receptors; 2nd type of muscle receptor, connects to tendons and sends out information about force produced by contraction |
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Definition
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Term
| As greater force develops during contractions, ___ generates more APs |
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Definition
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Term
| Term: Increasing motor units active in muscle |
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Definition
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