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Definition
| sometimes locomotion, sometimes movement within given area |
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| maintains body in stable positions |
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| heat production - as much as 85% of body heat is from muscle contractions |
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Definition
| contraction of sphincters may prevent outflow of contents of hollow organ |
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| Excitability (irritability) |
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Definition
| ability to receive and respond to stimuli |
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Definition
| ability to shorten and thicken |
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| ability to return to original shape after stretching |
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| striated, voluntary muscle |
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| visceral, involuntary muscle |
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Definition
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| - fibrous connective tissue sheath that envelops each muscle (around the muscle) |
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| partitions each muscle into fascicles or bundles of fibers |
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| extension between individual muscle fibers |
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| strong, tough cord, continuous at one end with fibrous wrappings of muscle and other end with periosteum |
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| - broad flat sheet of fibrous connective tissue continuous at one border with fibrous wrappings of muscle and at other border with fibrous coverings of adjacent structure, usually another muscle (ex. The tissue that holds the scalpulas together.) |
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| tubes of fibrous connective tissue that enclose certain tendons (wrist and ankle); synovial membrane lines tendon sheaths |
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Term
| Superficial fascia (subcutaneous layer) |
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Definition
Stores water and fat
Forms layer of insulation
Provides mechanical protection against blows
Provides pathway for nerves and blood vessels to enter and exit muscles |
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Definition
| layer of dense fibrous connective tissue underlying superficial fascia; extensions of deep fascia form epimysium, etc.; and also enclose viscera, glands, blood vessels, and nerves |
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Definition
| cell membrane of muscle fiber |
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Definition
| cytoplasm of muscle fiber |
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Definition
| smooth endoplasmic reticulum |
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Definition
| fine fibers packed close together in sarcoplasm; consist of 3 kinds of myofilaments |
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Definition
| section of myofibril between Z lines (Unit of muscle contraction) |
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Definition
| made of myosin molecules; heads of myosin are cross bridges of thick filaments |
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Definition
| - actin, tropomyosin, and troponin molecules arranged in complex fashion; contains myosin-binding site |
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Definition
| - titin (connectin); anchors thick filaments to Z discs; stabilizes thick filaments |
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Definition
| Dark Stripes, composed of both thick and thin filaments |
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Term
| H zone runs across midsection of each dark A band |
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Definition
| composed only of thick filaments |
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Definition
| - divides H zone; formed by protein molecules that connect adjacent thick filaments |
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Definition
| Light Stripes, - composed only of thin filaments |
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| Dark Z discs extends across center of each light I band |
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Definition
| - regions of dense material; separates sarcomeres |
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Term
| Sarcoplasmic reticulum (SR) |
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Definition
| encircles each myofibril; stores calcium; contains calcium release channels (pores) |
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Definition
| tunnel-like infoldings of sarcolemma in region of Z discs; on either side are dilated end sacs of SR called terminal cisterns |
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Definition
| triple-layered structure consisting of T tubule sandwiched between sacs of sarcoplasmic reticulum |
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| One motor neuron together with skeletal muscle fibers it supplies |
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Definition
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| Number of muscle fibers per motor unit varies |
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Definition
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| More precise movements produced by muscle in which motor units include fewer muscle fibers |
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Definition
| (voice 2-3 muscle fibers/unit; gross movements - gastrocnemius as many as 2000/unit) |
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Term
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Definition
| motor neuron and skeletal muscle |
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Term
| Axon of motor neuron branches into |
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Definition
| axon terminals which contain synaptic vescicles |
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Term
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Definition
| neurotransmitter substance, acetylcholine (ACh), which diffuses across synaptic cleft |
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| Muscle fiber contains motor end plate which contains |
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Definition
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| recognize and bind to ACh which opens channels for Na+ to diffuse into |
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Definition
| muscle fiber generating action potential which leads to muscle contraction |
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Definition
| Cross bridges of thick filaments (myosin) attach to thin filaments (actin) and pull them toward the middle of the sarcomere |
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Term
| In uncontracted state - calcium is |
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Definition
| stored in SR, ATP is attached to cross bridges, and tropomyosin-troponin complex is attached to calcium |
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Term
| Upon stimulation by nerve impulse, acetylcholine is |
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Definition
| by motor axon synaptic end bulbs |
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Term
| ACh diffuses across myoneural junction and |
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Definition
| initiates an action potential (movement of sodium into fiber and potassium out) |
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Definition
| T tubules to sarcoplasmic reticulum which releases its calcium by opening calcium release channels |
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Term
| Calcium ions combine with |
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Definition
| troponin causing troponin-tropomyosin complex to move which exposes the myosin-binding site on the actin molecule. |
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Term
| Energy released from ATP is used for |
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Definition
| attachment of myosin cross bridges to myosin-binding sites on actin; energy is then used to pull actin filaments inward (power stroke) resulting in sliding of thin filaments past thick filaments |
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Term
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Definition
| toward each other, sarcomere shortens, muscle fibers contract, muscle contracts |
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Term
| After action potential, ACh is |
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Definition
| inactivated by acetylcholinesterase (AChE) |
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Term
| calcium is transported back into |
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Definition
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Term
| tropomyosin-troponin complex reattaches |
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Definition
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| myosin cross bridges separate from |
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Definition
| actin; ATP is resynthesized; muscle relaxes |
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Term
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Definition
– Muscle fibers contain creatine phosphate (phosphocreatine) which breaks down to creatine + phosphate + energy
– 3-5 times more plentiful than ATP
– Used for maximal short bursts of energy (15 secs) |
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Term
| Phosphate and energy can be used to remake |
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Definition
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Term
| Glycogen-lactic acid system |
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Definition
When creatine phosphate gone, glucose catabolized and glycogen broken down
– If oxygen is not available, anaerobic respiration takes place in the form of glycolysis with formation of lactic acid and some energy (30-40 sec) |
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| Lactic acid diffuses into blood |
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Definition
| liver can convert lactic acid back to glucose |
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Definition
| – Activity longer than 30 sec. depends on aerobic process |
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| – With oxygen available cellular respiration occurs to produce |
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Definition
| ATP and carbon dioxide and water |
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Term
| oxygen comes from blood and is released from |
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Definition
| from myoglobin inside muscle fibers |
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Term
| – Provide ATP for prolonged activity as long as |
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Definition
| oxygen available and glucose available |
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Term
| Maximum rate of oxygen consumption is called |
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Definition
| maximal oxygen uptake; affected by gender, age, size, training |
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Term
| After heavy muscle activity |
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Definition
heavy breathing continues to repay oxygen used in activity (oxygen debt or recovery oxygen consumption)
All or none law |
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Term
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Definition
| contract with all force possible under existing conditions or do not contract at all |
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Term
| Tonic contraction (tone, tonus) |
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Definition
– Continual, partial contractions produced by simultaneous activation of small group of motor units, followed by relaxation of their fibers and activation of another group of motor units
– Specialized receptors called muscle spindles and neurotendinous end-organs detect degree of muscle stretch |
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Definition
| muscle shortens but its tension remains constant; isotonic contractions produce movements |
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Definition
| muscle shortens and pulls on another structure to produce movement and reduce angle of joint |
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Term
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Definition
| - overall length of muscle increases (repeated contractions produce more muscle damage than concentric) |
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Term
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Definition
| muscle length remains unchanged but tension within muscle increases; isometric contractions “tighten” muscles but do not produce movements; energy expended |
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Term
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Definition
| quick, jerky contraction in response to single stimulus; consists of 3 phases - latent period(before the muscle contracts), contraction phase, and relaxation phase; rare in normal body |
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Term
| Tetanic contraction (tetanus) |
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Definition
| sustained smooth contraction produced by series of stimuli bombarding muscle in rapid succession |
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Term
| Treppe (staircase phenomenon) |
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Definition
| series of increasingly stronger contractions in response to constant-strength stimuli applied at rate of 1 or 2 per second (ex) Getting your muscles to warm up before an athletic event!) |
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Term
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Definition
| incomplete relaxation after repeated stimulation (ex. Like Kale’s mom-with her curled up arm and hand-you can’t relax it)[Hannah-you wouldn't understand. lol] |
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Term
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Definition
| failure of muscle to contract in response to strongest stimuli after repeated stimulation; true muscle fatigue seldom occurs in body (It seldom occur-we can usually get some response from our muscles) |
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Definition
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Term
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Definition
| high myoglobin(Stores oxygen) content; more mitochondria and blood capillaries. (Muscles are used the most, ex. Chicken-white and dark meat. Dark meat are in the legs-and contract a lot more-meaning they need more oxygen and glucose. The breast wouldn’t be as much) |
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Term
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Definition
| low myoglobin content (ex. Chicken breast) [This is a generality. |
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Term
| Slow oxidative (type I) fibers (slow twitch or fatigue-resistant fibers) |
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Definition
• Look red and have high capacity to generate ATP by aerobic system
• Split ATP at slow rate so have slow contraction velocity
• Resistant to fatigue; capable of prolonged, sustained contractions
• Found in head and neck muscles(posture, marathon runners have these types of fibers) |
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Term
| Fast oxidative (type II) fibers (fast-twitch A or fatigue-resistant fibers) |
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Definition
• Look red and have high capacity to generate ATP
• Split ATP rapidly and have fast contraction velocity
• Resistant to fatigue
• Found in sprinter's leg muscles (walking, running) |
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Term
| Fast glycolytic (type II) fibers (fast-twitch B or fatigable fibers) |
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Definition
• Look white; contain lots of glycogen
• Generate ATP by anaerobic processes so fatigue easily
• Largest diameter fibers
• Split ATP fast so strong, rapid contraction
• Muscles of arm (weight lifting, throwing) |
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Term
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Definition
| quadrangular shaped and single nucleus [Fibers are striated, intercalated discs] |
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Term
| Fibers branch interconnect |
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Definition
| with each other; intercalated discs are irregular transverse thickenings of sarcolemma that connects neighboring fibers |
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Term
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Definition
| one in atria and one in ventricles; allows entire network to contract together |
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Term
| Cardiac muscles Contracts and relaxes an average |
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Definition
| 75 times/minute thus requiring constant oxygen supply [Needs to create ATP] |
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Term
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Definition
| Contains more mitochondria than skeletal muscle so depends on aerobic system to generate ATP |
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Term
| Cardiac muscle can contract without |
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Definition
| extrinsic stimulus; has specialized conducting network within heart (autorhythmicity) |
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Term
| Remains contracted 10-15 times longer than skeletal muscle but also |
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Definition
| has long refractor period |
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Term
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Definition
| Smaller fibers than skeletal; thickest in middle and tapered at ends with single nucleus in middle |
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Term
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Definition
| Contains thick and thin filaments but not arranged in sarcomeres as in [skeletal and cardiac] striated muscle |
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Term
| Smooth muscles contain what kind of filaments |
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Definition
| Contain intermediate filaments which attach to structures called dense bodies (similar to Z discs); some dense bodies are scattered in sarcoplasm and some attach to -sarcolemma [shortens the cell=lengthwise shortening of muscle fibers] |
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Term
| Bundles of intermediate fibers stretch from |
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Definition
| one dense body to another; contraction causes intermediate filaments to pull on dense bodies causing a lengthwise shortening of muscle fiber |
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Term
| Two types of smooth muscles |
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Definition
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Term
| Visceral (single unit) smooth muscle |
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Definition
| most common; forms part of walls of small arteries and veins and hollow viscera such as stomach, intestines, uterus, and bladder; contain gap junctions which allows stimulation of many fibers at once |
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Term
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Definition
| individual fibers each with own motor neuron terminals and with few gap junctions between neighboring fibers; stimulation causes contraction of only one fiber; found in walls of large arteries, in large airways of lungs, in arrector pili muscles, and in radial and circular muscles of iris [When the stimulus comes-it only stimulates one or two fibers-this is from more precise movements. These are found in the arteries, the bronchi of the lungs] |
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Term
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Definition
| more slowly and lasts longer than striated muscle; can shorten and stretch more than striated |
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Term
| No T tubules and calcium enters through |
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Definition
| sarcolemma as well as released from SR |
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Term
| Contains calmodulin (it’s like troponin) and myosin light chain kinase which are needed for myosin binding to actin |
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Definition
| for myosin binding to actin |
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Term
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Definition
| mesoderm pg. 357 (good comparison chart for muscles) 358 (Developmental anatomy) |
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Term
| Calcium moves slowly out of cell, which delays |
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Definition
| relaxation resulting in prolonged muscle tone |
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Term
| Smooth muscle contraction is controlled |
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Definition
| by the autonomic nervous system |
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Term
| Muscles arise from mesoderm except |
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Definition
| for muscles of iris and arrector pili muscles |
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Term
| Mesoderm forms somites (segmented blocks) |
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Definition
| 1st pair appears at 20 days and by 30 days have all 44 pairs of somites |
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Definition
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Definition
| forms connective tissue and dermis |
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Definition
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| Cardiac and smooth muscle develop from |
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Definition
| other mesodermal cells (primarily splanchnic mesoderm) |
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