Term
| contraction of skeletal muscle fiber is by |
|
Definition
| lower motor neuron of somatic nervous system |
|
|
Term
| a chemical synapse between lower motor neuron and muscle fiber (neuromuscular junction) occurs at |
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Definition
|
|
Term
|
Definition
| specialized, highly excitable region of muscle fiber |
|
|
Term
| Excitation-Contraction Coupling |
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Definition
| process by which muscle fiber excitation causes muscle fiber contraction |
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|
Term
| what is shortened during contraction? |
|
Definition
1) sarcomere
2) I band
3) H zone |
|
|
Term
| what remains unchanged during contraction? |
|
Definition
1) A band
2) thin filament
3) thick filament |
|
|
Term
| length-tension relationship |
|
Definition
| relationship between sarcomere length and tension produced during contraction |
|
|
Term
| sarcomere length of 2.0 to 2.25 µm |
|
Definition
1) allows for maximum number of cross bridges
2) distance for sliding of thin filaments is relatively large |
|
|
Term
| what sarcomere length generates the greatest amount of tension? |
|
Definition
| sarcomere length of 2.0 to 2.25 µm |
|
|
Term
| what sarcomere length reduces the tension generated? |
|
Definition
1) sarcomere length greater than 2.25 µm
2) sarcomere length less than 2.0 µm |
|
|
Term
| sarcomere length greater than 2.25 µm |
|
Definition
1) distance for sliding of thin filaments is large
2) number of cross bridges is limited due to less action (myosin overlap) |
|
|
Term
| sarcomere length less than 2.0 µm |
|
Definition
1) allows for the maximum number of cross bridges
2) distance for sliding of thin filament is limited |
|
|
Term
|
Definition
| single contraction of a single muscle fiber in response to a single stimulus |
|
|
Term
|
Definition
| time between stimulus and beginning of contraction |
|
|
Term
| what happens during the lag phase? |
|
Definition
| generation of action potential to revealing of active sites |
|
|
Term
|
Definition
| time during which contraction occurs |
|
|
Term
| what happens during the contraction phase? |
|
Definition
| binding of myosin head to sliding of thin filament medially |
|
|
Term
|
Definition
| time during which relaxation occurs |
|
|
Term
| what happens during the relaxation phase? |
|
Definition
| ATP binding myosin head to sliding of thin filament laterally |
|
|
Term
| does the magnitude of a twitch change with increased strength of stimulus? |
|
Definition
| NO - increasing the stimulus will not cause more calcium to be released |
|
|
Term
| multiple - wave summation/temporal summation |
|
Definition
| successive multiple twitches in response to successive stimuli |
|
|
Term
| what happens to the phases during a multiple-wave summation? |
|
Definition
1) lag phase and relaxation phase shorten
2) contraction phase lengthens |
|
|
Term
|
Definition
| sustained contraction due to a maximal frequency of stimuli |
|
|
Term
| what happens to the phases during tetanus? |
|
Definition
1) lag phase and relaxation disappear
2) contraction phase is constant |
|
|
Term
|
Definition
| single motor neuron and the muscle fiber(s) it innervates |
|
|
Term
| fewer muscle fibers in a motor unit |
|
Definition
allows for finer movements
[intrinsic hand muscles] |
|
|
Term
| greater muscle fibers in a motor unit |
|
Definition
slow reacting muscles
[postural muscles, leg muscles, back muscles] |
|
|
Term
| multiple motor unit summation/spatial summation |
|
Definition
| larger stimulus = greater numbers of motor units = increase tension generated |
|
|
Term
| two main types of muscle contraction |
|
Definition
|
|
Term
|
Definition
| contraction in which muscle length changes (shortens/lengthens) |
|
|
Term
|
Definition
1) concentric
2) eccentric |
|
|
Term
|
Definition
| contraction in which muscle length does not change; muscle tension equals or does not exceed resistance |
|
|
Term
|
Definition
| muscle tension exceeds resistance and thus muscle shortens |
|
|
Term
|
Definition
| resistance exceeds tension and thus muscle lengthens |
|
|
Term
|
Definition
| state of partial, muscle contraction due to nerves continually stimulating motor units |
|
|
Term
| decreased muscle tone with lower motor neuron dysfunction occurs in |
|
Definition
| neuropathies, ALS, botox injection |
|
|
Term
| increased muscle tone with upper motor neuron dysfunction occurs with |
|
Definition
|
|
Term
|
Definition
| involuntary and forcible contracture of muscle with failure to relax |
|
|
Term
| common causes of muscle cramps |
|
Definition
1) fatigue (low ATP)
2) low extracellular calcium (calcium stabilizes membranes)
3) dehydration |
|
|
Term
|
Definition
| electrolyte and fluid imbalance |
|
|
Term
|
Definition
| muscle weakness - NOT muscle cramps |
|
|
Term
|
Definition
| state of constant muscle rigidity that occurs several hours after death |
|
|
Term
| why does rigor mortis occur? |
|
Definition
| due to complete depletion of ATP (does not allow myosin heads to release actin) |
|
|
Term
|
Definition
| immediate source of energy; exists a limited storage supply that provides only a few seconds of energy |
|
|
Term
|
Definition
1) Creatine phosphate/ Phosphocreatine
2) glycogen
3) fat
4) protein |
|
|
Term
|
Definition
| breaks down to provide phosphate to produce ATP |
|
|
Term
| glycogen needs to be broken down into |
|
Definition
|
|
Term
| glycogen is the storage form of glucose in |
|
Definition
|
|
Term
| when is glycogen preferentially utilized? |
|
Definition
| during moderate to high intensity exercise |
|
|
Term
| fat needs to be broken down into |
|
Definition
|
|
Term
| when is fat preferentially utilized? |
|
Definition
| during low to moderate exercise |
|
|
Term
| protein needs to be broken down into |
|
Definition
|
|
Term
| when is protein utilized? |
|
Definition
| when glycogen and fats are depleted |
|
|
Term
|
Definition
| dangerous nitrogenous waste product - ammonia |
|
|
Term
|
Definition
1) phosphagen system
2) anaerobic respiration
3) aerobic respiration |
|
|
Term
| duration of energy provided by phosphagen system |
|
Definition
|
|
Term
| duration of energy provided by anaerobic respiration |
|
Definition
|
|
Term
| duration of energy provided by aerobic respiration |
|
Definition
|
|
Term
| what happens in the phosphagen system? |
|
Definition
| phosphocreatine donates a phosphate to ADP which causes ADP -> ATP |
|
|
Term
| anaerobic respiration is the preferred process for |
|
Definition
|
|
Term
| ATP yield in anaerobic respiration |
|
Definition
| one glucose molecule yields two ATP molecules |
|
|
Term
| source of energy in anaerobic respiration |
|
Definition
|
|
Term
| waste product of anaerobic respiration |
|
Definition
| lactic acid (thought to contribute to muscle fatigue) |
|
|
Term
| aerobic respiration is the preferred process |
|
Definition
|
|
Term
| ATP yield in aerobic respiration |
|
Definition
| one glucose molecule yields 36 ATP molecules |
|
|
Term
| source of energy in aerobic respiration |
|
Definition
| glucose, fatty acids, or amino acids |
|
|
Term
|
Definition
1) psychological fatigue
2) muscular fatigue
3) synaptic fatigue |
|
|
Term
| psychological fatigue might be linked to |
|
Definition
|
|
Term
| during psychological fatigue |
|
Definition
| interleukin 6 is produced during physical exertion which signals the brain to feel tired |
|
|
Term
|
Definition
1) depletion of ATP
2) accumulation of potassium outside of muscle fiber
3) accumulation of phosphate inside of muscle fiber
4) accumulation of lactic acid |
|
|
Term
|
Definition
| dysfunction at the neuromuscular junction |
|
|
Term
| synaptic fatigue disorders |
|
Definition
1) myasthenia gravis
2) Lambert-Eaton myasthenia syndrome |
|
|
Term
|
Definition
| autoimmune destruction of nicotinic ACh receptors |
|
|
Term
| Lambert-Eaton myasthenia syndrome |
|
Definition
| autoimmune destruction of pre-synaptic calcium channels; causes decreased release of ACh |
|
|
Term
|
Definition
1) red, slow twitch fibers (Type I)
2) white, fast twitch fibers (Type IIb)
3) intermediate fibers (Type IIa) |
|
|
Term
| red, slow twitch fibers (Type I) |
|
Definition
1) fatigue resistant (slow oxidative)
2) contract slowly
3) relax slowly |
|
|
Term
| red, slow twitch fibers (Type I) are suited for |
|
Definition
|
|
Term
| white, fast twitch fibers (Type IIb) |
|
Definition
1) high concentration of glycogen (fast glycolytic)
2) very low concentration of myoglobin
3) more ATP produced anaerobically
4) contract rapidly
5) relax rapidly |
|
|
Term
| red, slow twitch fibers (Type I) are fatigue resistant due to |
|
Definition
1) high concentration of mitochondria
2) high concentration of myoglobin
3) more ATP produced aerobically |
|
|
Term
| red, slow twitch fibers (Type I) contract slowly due to |
|
Definition
1) slower myosin cross-bridge cycling
2) slower ATPase activity |
|
|
Term
| red, slow twitch fibers (Type I) relax slowly due to |
|
Definition
|
|
Term
| white, fast twitch fibers (Type IIb) contract rapidly due to |
|
Definition
1) faster myosin cross-bridge cycling
2) faster ATPase activity |
|
|
Term
| white, fast twitch fibers (Type IIb) relax rapidly due to |
|
Definition
|
|
Term
| intermediate fibers (Type IIa) |
|
Definition
| fast twitch and fatigue resistant (fast oxidative - glycolytic) |
|
|
Term
| compared to Type I fibers, Type IIa fibers |
|
Definition
| are not quite as resistant to fatigue as Type I fibers |
|
|
Term
|
Definition
| protein that prevents hyperplasia and to a small extent, hypertrophy in skeletal muscle |
|
|
Term
|
Definition
|
|
Term
|
Definition
|
|
Term
| inhibition of myostatin gene |
|
Definition
1) beneficial in muscle wasting disease
2) allows muscle cells to grow via hyperplasia
3) muscle mass sustained for longer period of time |
|
|
Term
| conditions that cause muscles to waste |
|
Definition
1) muscular dystrophy
2) cancer
3) injury |
|
|
Term
| two major types of smooth muscle arrangement |
|
Definition
1) single-unit/unitary/visceral
2) multiunit |
|
|
Term
| what is the most common type of smooth muscle arrangement? |
|
Definition
| single-unit/unitary/visceral |
|
|
Term
| the single-unit/unitary/visceral is composed of |
|
Definition
| syncitium and couple by gap junctions |
|
|
Term
|
Definition
|
|
Term
| where are single-unit/unitary/visceral found? |
|
Definition
| in walls of digestive tract, blood vessels, ureters, uterus |
|
|
Term
| stimulation of single-unit/unitary/visceral |
|
Definition
| stimulation of one cell excites adjacent cells |
|
|
Term
|
Definition
1) less well-organized
2) function independently of each other |
|
|
Term
| where are multiunit found? |
|
Definition
| arector pili, iris and walls of some small blood vessels |
|
|
Term
| smooth muscle characteristics |
|
Definition
1) involuntary
2) myofibrils more randomly organized
3) sarcoplasmic reticulum not well developed
4) calcium release is both intracellular and extracellular
5) lack T tubules |
|
|
Term
| calcium release in smooth muscle |
|
Definition
1) most calcium released from calcium channels of sarcolemma (extracellular)
2) very little calcium comes from sarcoplasmic reticulum (intracellular) |
|
|
Term
| calcium binding protein in smooth muscle |
|
Definition
|
|
Term
| anchoring of actin in smooth muscle |
|
Definition
1) to dense bodies located in sarcoplasm
2) to dense areas attached to sarcolemma |
|
|
Term
| cardiac muscle characteristics |
|
Definition
1) involuntary
2) striated
3) well-developed sarcoplasmic reticulum
4) contains T tubules
5) calcium released is both intracellular and extracellular |
|
|
Term
| calcium release in cardiac muscle |
|
Definition
1) from calcium channels of sarcolemma (by action potentials that conduct along sarcolemma)
2) from sarcoplasmic reticulum |
|
|
Term
|
Definition
| cross bands that connect opposing ends of cardiac muscle fibers |
|
|
Term
| intercalated discs help form |
|
Definition
| a sheet of cardiac muscle cells (syncitium) |
|
|
Term
| the sheet of cardiac muscle cells allows |
|
Definition
| cardiac muscle cells to contract in a coordinated manner |
|
|
