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Physio Ch. 9
| Question | Answer |
|---|---|
| muscle breakdown | tendon, muscle, CT and bloodvessels, muscle fiber, myofibril, sarcomere, actin and myosin |
| myofibrils have what three structures | a band, i band, z lines |
| sarcomeres have | z line, m line, h zone |
| thick filament is...thin filament is... | myosin...actin |
| myofibril of muscle fiber is a collection of | protein fibers in muscle cells |
| myofibril's sarcomere is the...unit containing... | contracting...thin and thick filaments |
| myofiber/muscle fiber also has the... | sarcolemma and the sarcoplasmic reticulum |
| neural control of skeletal muscle: ...division and more specifically... | efferent...somatic motor |
| neural control of skeletal muscle has what kind of junction and also the... | neuromuscular junction...motor end plate |
| skeletal muscle contraction: myofiber excitation | neuromuscular junction stimulation and excitation of sarcolemma |
| skeletal muscle contraction: ...coupling: opening of...to release... | excitation-contraction...sarcoplasmic reticulum...ca to cytosol |
| skeletal muscle contraction: cross bridge cycling: interaction between...and...use | actin and myosin...atp |
| myofiber relaxation: stop...and.,.. | excitation..return cell to 'normal' |
| contraction and relaxation depends on | cross bridge action |
| accordig to the sliding filament mechanism what changes length? | length of the sarcomere |
| motor unit | motor neuron innervating each myofiber or multiple myofibers |
| ...innervates each motor unit | 1 somatic motor neuron |
| motor unit number of arrangement | 1:10, 1:100, 1:1000 |
| one AP in a motor unit -> | one contraction of entire motor unit |
| consequences of motor unit arrangement: direct relationship with...indirect with... | strength...control |
| the larger the motor unit the...and the smaller the unit the... | less precision..more precision |
| neuromuscular junctions are also called | neuroeffector junction |
| axon terminal of neuromuscular junction | efferent division - somatic motor |
| the neurotransmitter for neuromuscular junctions is | ach |
| motor end plate of neuromuscular junction contains | ach receptors (nicotinic) and ache |
| end plate potential (EPP) is a...and is...only | graded potential...excitatory (very easy to excite) |
| only one epp necessary for | sarcolemma depolarization and AP |
| sarcolemma AP depolarization is | bi-directional meaning an AP is happening in the middle of postsynaptic neuron so it can go out to the left or right, just not backwards |
| neuromuscular junctions end with a | muscle action potential |
| events at the neuromuscular junction 1-8 | 1. neuron AP 2. ca enters voltage gated channels 3: ach is released 4. ach binds to receptors 5. the binding opens ligan gated na channels 6. EPP is caused by the opening of na channels 7. voltage gated na channels open 8. bidirectional propagation of ap |
| event at the neuromuscular junction step 9 | ache and dimished stimulation |
| ache is | always working - as long as you release more ach than is being destroyed, the voltage gated na channels will remain open |
| problems with skeletal muscle excitation | curare, nerve gas, botulism, tetanus |
| curare binds to | ach receptors but no epp because no channels are opened and it is not affected by ache because it is the wrong shape |
| curare leads to | paralysis |
| nerve gas inhibits...so... | ache...ach remains at receptors and eventually the receptors become desensitized to ACh which leads to paralysis |
| botulism reduces..thus it effects... | release of ach from axon terminals...presynaptic neurons |
| tetanus blocks | neurotransmitter release to inhibitory neurons so it causes spasms |
| excitation-contraction coupling goes from...to.. | muscle fiber AP...muscle contraction |
| muscle fiber ap | neuron stimulation - epp |
| latent period 3 things occur | sarcoplasmic reticulum releases ca, ca goes into the cell, ca binds to troponin |
| muscle contraction | cross-bridge cycling increases force = movement of actin/myosin |
| muscle relaxation | ca sequestered (break cross bridge between actin and myosin) |
| transfer of muscle ap to sarcoplasmsic reticulum goes from..to... | t tubules...lateral sacs of sarcoplasmic reticulum |
| t tubule: axon potential travels | here to open right next to the SR |
| lateral sacs are also called the...and is where... | terminal cisternae...ca is stored |
| t tubules have...known as... | junctional feet...dihydropyridine receptors (DHP) |
| dhp is...meaning it is a... | voltage activated...voltage receptor |
| ap changes shape of | dhp |
| dhp is physically connected to | ryanodine receptors in SR |
| SR ryanodine receptor is...and lets...out of the sr via... | mechanically gated...ca...channels |
| ca atpase pump puts | ca back into the SR |
| release and uptake of ca by the SR during contraction and relaxation of a skeletal muscle fiber has 6 steps | 1. muscle AP propogated into t tubule 2. junctional feet -DHP -ryanodine activation with ca release 3. ca and troponin interaction to remove blocking action of tropomyosin 4. cross bridge formation 5. ca uptake 6. ca removed from tropo/tropom blocks |
| cross bridge cycling structures | myosin and actin |
| myosin is shaped like...and has two parts... | golf club...tail and head |
| tail of myosin | heavy chains |
| head/cross bridge are made of...which contains two sites | heavy chain...actin binding site(what the head interacts with) and atp binding site/atpase |
| heads/cross bridges also have | light chain (smooth muscle function) |
| actin is made of a...which is the site for... | polymer helical chain...cross bridge binding |
| actin also has | tropomyosin covering the myosin binding site and troponin that moves the tropomyosin out of the way |
| initiation of cross bridge cycling 3 steps | ca enters cytosol, ca binds to troponin c, tropomyosin is shifted |
| myosin moves | actin in to shorten the sarcomere |
| mechanism of cross bridge cycling 1: | cross bridge formation which is the link between actin and myosin |
| mechanism of cross bridge cycling 2: | power stroke and adp release on myosin head in order to bind to actin |
| mechanism of cross bridge cycling 3: ...which causes... | atp binding ... myosin-actin dissociation |
| if there is no atp in cross bridging it leads to...or.. | rigor mortis...cramps |
| mechanism of cross bridge cycling 4: | cross bridge energized |
| cross bridge cycling goes as long as | tropomyosin is out of the way which it is out of the way as long as ca is bound to troponin |
| skeletal muscle relaxation involves no...which means... | neuron AP...no additional ACh release |
| no addition ach release in skeletal muscle relaxtion means...which means... | ache activity...no epp |
| no epp means that there is..activity to put... | ca atpase...ca backk into the longitudinal elements of the SR |
| final stages of muscle relaxation | tropomyosin shifts back over the actin-myosin binding sites thus there is no cross bridge formation |
| tension | muscle strength or tone |
| load = | object force is exerted upon or the weight |
| tension developed by myofiber = | force exerted |
| force exerted = load effect | nothing |
| force exerted > load effect | shorten muscle to lift the load |
| force exerted < load effect | put load down |
| isometric muscle contraction = | same length or tension = load |
| isometric holds...or...position | load steady...constant |
| if tension is less than load then the load | can't be moved bec enough force can't be developed |
| in isometric muscle contraction what is maintained | sarcomere length |
| the sarcomere of an isometric muscle contraction may...but...and it...force to... | shorten...elastic components of the myofibers extend to make overall change zero...passively transmit...ends of muscle |
| isotonic muscle contractions =...meaning that the muscle maintains...or the muscle may... | same tension...same tension...shorten or lengthen |
| concentric muscle movement or contraction means the muscle is... | actively shortened (stepping up) and the tension > load |
| the sarcomere length of a concentric muscle movement is | decreased |
| eccentric muscle movement or contraction the muscle is actively...meaning...and the sarcomere length is... | lengthened...tension < load to lower the load...increased |
| a twitch is...->... | one ap...one epp |
| twitches affect one | myofiber and not the whole muscle |
| isometric twitch contraction the tension...and there is a...which is when...occurs | = load...latent period...excitation-contraction coupling |
| contraction time for an isometric twitch contractions is roughly...and to relax is you have to... | 140 msec...release tension |
| after you've had a...you can have a... | isometric twitch...isotonic twitch |
| isotonic twitches occur when tension...and during the...a couple things occur such as... | > load...latent period...exictation-contraction coupling and isometric contraction |
| contraction time of isotonic twich is roughly | 50-70 msec |
| length represents | force |
| relationship between isometric and isotonic twitches | tension must = load before it can exceed it |
| isotonic twitches load v. latent period | ^ > ^ (takes more time to shorten muscle) |
| isotonic twitches load v velocity | ^ > \/ (heavy load = slower speed) |
| frequency v tension depends on | stimulus duration, twitch duration, summation and tetanus |
| stimulus duration: 1 ap = | 1 twich that lasts about 1-2 msec(myofiber ap) |
| twitch duration | 10 msec to 100+ msec |
| summation applies | additional stimulus while partial contraction is occuring |
| tetanus can be either | fused (no relaxation) or unfused (some relaxation) |
| maximal fused tetanus leads to | extended work, muscle cramps and fatigue |
| length v tension can either be | passive or active |
| passive tension comes from...and there is no... | tissue itself...cross-bridge cycling or atp |
| passive tension involves | titin w/i sarcomeres and CT between myofibers and in muscles |
| passive tension: stretch of | myofibril increases passive tension- no cross bridge cycling |
| tension increases | stretch to develope force in passive tension |
| active tension involves | actin myosin cross bridges and altered sarcomere length |
| sarcomere length alters active tension meaning length can be | optimal (lo, right amoutn of actin/myosin overlap to develope force), length < 60% lo or > 175% lo |
| active tension muscle length is restricted by..which ranges between...at approx... | skeletal structure...70-130% lo...50%max tension |
| diameter v tension and velocity | ^ diameter of myofiber > # of myofilaments (^ tension and ^ velocity) |
| atp is required to | energize myosin head for power stroke, release cross bridges (rigor mortis) and for the ca atpase pump |
| atp sources for skeletal muscle metabolism | aerobic cell resp, anaerobic cell resp, creatine phosphate |
| atp from...is replenished while... | aerobic and anaerobic...muscles work |
| once creatine phosphate's atp is used | no more can be created until the muscle stops working |
| aerobic and anaerobic cell resp get atp from | food |
| creatine phosphate is located in...where it is... | skeletal muscles...stored |
| aerobic respiration includes...and is..but has high... | glycolysis and oxidative phosphorylation...slow...atp production |
| aerobic resp produces...and depends on... | atp from food breakdown...amount of myoglobin, # of mito, o2 & nutrient availability, waste removal |
| anaerobic resp includes...and is..but... | glycolysis and fermentation...faster...low atp production per glucose molecule |
| anaerobic produces..and can produce...and depends on... | atp from food breakdown...large amounts of atp...nutrient availability and waste removal |
| creatine phosphateis a..system; it is the...and only takes... | phophagen...fastest...energy out of temporary storage |
| creatine phoshpate depends on | cellular creatine phosphate concentraion |
| oxgyen debt is also called | recovery |
| oxygen debt means that | o2 consumption is elevated after exercise |
| oxygen debt results in...which can be used as an energy source in... | lactic acid metabolism...kidneys, liver and heart |
| oxygen debt replenishes...and also results in the production of... | muscle glycogen (storage of glucose)...creatine phosphate |
| muscle fatigue is a loss of..and involves | tension..rest and recovery |
| high frequency fatigue results from | high intensity, short duration exercise (burst of activity like weight lifting) |
| low frequency fatigue results from | low intensity, long duration exercise (cyclic contraction and relaxation) |
| factors associated with fatigue | muscle AP conduction failure, lactic acid build up, inhibition of cross bridge cycling, low glycogen and blood sugar levels, dehydration |
| muscle AP conduction failure means excess...and constant... | k in t tubules...depolarization and inactivation of voltage gated na channels |
| lactic acid build up changes...and reduces..and results in... | pH of muscles...activity of ca pumps...poor relaxation of fatigued muscles |
| inhibition of cross bridge cycling ^ | atp use and adp + Pi build up |
| inhibition of cross bridge cycling is an inhibition in step...but it protects against... | 2...dramatic decline of ATP (rigor mortis) |
| low glycogen and blood sugar levels depends on | nutrient availability |
| central command fatigue always involves | cns |
| central command fatigue has no...which means that muscles... | signals from the cns...are not necessarily fatigued |
| maximal velocities of shortening include two types of fibers | fast twitch and slow |
| fast twitch fibers involve...which makes..happen... | myosin w/ high atpase activity...cross bridge cycling...4x faster |
| slow twitch fibers involve...which makes the...occur... | myosin w/ low atpase activity...cross bridge...slower |
| pathway of atp production occurs via | oxidative fibers or glycolytic fibers |
| oxidative fibers use...have what kind of diameter...and many | o2...small fiber diameter...mitochondria |
| oxidative fibers = ^ | myoglobin and blood supply (red fibers) |
| glyolytic fibers have...with...and \/ | large fiber diameter...fewer mitochondria...myglobin and blood supply to make white fibers |
| type 1 fibers are called...and they | slow oxidative..resist fatigue |
| type 1 decrease size > | decrease maximal tension |
| type 1 have slow atpase= | oxygen can keep up and good endurance |
| type 2a are called....and have an...rate | fast-oxidative-glycolytic..intermediate fatigue |
| type 2a: increase size > | increase maximal tension |
| type 2b are called...and they... | fast-glycolytic...fatigue quickly |
| type 2b: ^^ size > | ^^maximal tension |
| motor unit recruitment...to increase... | stimulate more motor units...tension and velocity |
| a motor unit is the | motor neuron and all the myofibers it innervates |
| tension developed by each fiber depends on | ap frequency, fiber length, diameter and fatigue |
| factors that determine muscle tension depend on the # of... | active fibers (number of fiber per motor unit and number of active motor units) |
| atrophy | decrease size of muscle bec of denervation or disuse |
| hypertrophy | increase size bec of increased use |
| changes in muscle result from changes in... | size of fibers not the number of myofibers |
| changes in muscle also result from | metabolic activity of fibers |
| poliomyelitis is caused by | neural damage to somatic motor neuron cell body in spinal cord |
| poliomyelitis causes a lack of...which impacts...and results in.. | stimulation...individual motor units...flaccid paralysis |
| muscle cramps or muscle...result from | tetani...ion imbalance and hypocalcemia |
| ion imalance for muscle tetani include which ions | k, ca, s mg |
| muscular dystrophy is a...resulting from | genetic disorder...lack of dystrophin |
| lack of dystrophin in muscular dystrophy means there is no | pulling ability to cause tension |
| muscular dystrophy leads to | degradation of muscle cells |
| myasthenia gravis is decrease in...which reduces... | sensitivity to ach..EPP=no ap=no contraction |
Created by:
handrzej
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