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Chp 9 muscles
Bio 260 brulte/ marieb/ chp 9 muscles
| Question | Answer |
|---|---|
| Name the 3 types of muscle tissue | Smooth CarS = smooth;cardiac,skeletal |
| What are elongated cells capable of contracting along its longitudinal axis? | muscle fibers |
| ___ muscle pushes fluids and solids along digestive tract | smooth |
| ____ muscle pushes blood through the arteries & veins of circulatory sys | cardiac |
| Name the 4 basic properties all muscle tissue share: | 1)excitability 2)contractility 3) extensibility 4) elasticity |
| What is the ability to respond to stimulation? | excitability; skeletal muscles respond to stim by the nervous system; smooth muscles respond to hormones |
| ______ or the ability to shorten actively and exert a pull or tension that can be harnessed by C.T. | contractility |
| _____ or the ability to continue contracting after rest periods | Extensibility |
| _____ or the ability of a muscle to rebound top its original length after contraction | Elasticity |
| The muscular system includes ____ skeletal muscles that can be controlled _____ | 700; voluntarily |
| What are skeletal muscles? | contractile organs directly or indirectly attached to the bones of the skeleton |
| Name 5 FX of the skeletal muscle | Maintain BP Move Support & Regulate: maintain body temp & posture; produce movement; support S/T; regulate entering/exiting of material |
| What is an example of skeletal movement? | muscle contractions pull on tendons & move the bones of the skeleton for moving your arm or coordinated avtivity like running |
| What is an example of manintaing Body Posture? | constant muscular contraction of muscles keeps our head upright or joints to stabilize our walk |
| How do skeletal muscles support soft tissues? | abdominal wall and floor of pelvic cavity have layers of skeletal muscle that protect visceral organs |
| How does contracting skeletal muscle maintain body temp? | contraction requires energy and some energy is converted to heat;heat lost keeps body temp regulated |
| How do skeletal muscles regulate entering and exiting of material? | digestive and urinary system are lined with muscles to provide voluntary control |
| Greek word for "sarkos" | flesh |
| Greek word for "mys" | muscle |
| What are the 3 layers of CT that all skeletal muscles have? | 1) Epimysium = surrounds entire skeletal muscle2) Perimysium = divides groups of muscles & have blood vessels & nerves3) Endomysium = internally surrounds each muscle fiber & binds it to its neighbors |
| The _____ is the dense irregular C.T. that surrounds entire skeletal muscle & is connecred to deep fascia. | Epimysium |
| ___ C.T. contains collagen & elastic fibers and divides muscles into bundles of fibers or fasicles. | Perimysium |
| The Endomysium consists of ______ fibers (type of C.T. proper) | Reticular |
| The C.T. fibers of Endomysium and ___ are interwoven; | perimysium |
| What lies between the Endomysium and muscle fibers? | Satellite cells (FX in the repair of damaged tissue) |
| Perimysium blends into ____ | Epimysium |
| At the end of the muscle, the collagen fibers of Epimysium,Perimysium,and Endomysium converge to form a ___ or thick cords/cables. | tendon;attaches muscle to bone,skin or another muscle |
| Tendons that form thick,flattened sheets are ____ | aponeuroses |
| Where do chemical communication between synaptic terminal of neuron and skeletal muscle fiber occur? | neuromuscular junction or myoneural junction |
| How many neuromuscular junctions does each muscle fiber have? | one;located midway |
| What is the motor end plate of the muscle fiber that the neuromuscular junction is attached to? | specialized area of cell muscle membrane |
| How do the capillaries that that deliver oxygen and nutrients to each muscle fiber tolerate contractions? | capillaries are coiled rather than straight |
| The cell membrane of muscle fiber | sarcolemma |
| Sarcoplasm or _____ surrounds the skeletal muscle fiber | cytoplasm |
| What are some diff. of a skeletal msucle fiber (SMF) compared to a regular cell | 1) SMF are very large2) multinucleated due to myoblasts during early development3) indentations in sarcolemma (cell membrane) form T tubules or transverse tubules |
| What are the adult "myoblasts" called when they remain in the adult SM tissue? | Satellite cells; FX differentiate (specialize) & assist cell repair /regeneration when SMF is injured |
| What do the electrical impulses of the T tubules of the sarcolemma do? | help stimulate & coordinate muscle contractions |
| What are Myofibrils? | cylindrical structures attached to sarcolemma (cell membrane);sarcoplasm has hundreds to thousands of myofibrils |
| What is the FX of Myofibrils? | responsible for muscle contraction since Myofibrils can shorten the entire cell |
| What surrounds each myofibril? | sleeve of membrane called SR (Sarcoplasmic reticulum) |
| What is the FX of the SR sarcoplasmic reticulum? | Closely associated with Transverse Tubules and controlling contraction of myofibril |
| What structure is located on either side of the Transverse tubule? | Terminal Cisternae;tubules of SR enlarge and fuse to form expanded chambers |
| What makes up the triad? | pair of terminal cisternae (chambers) & a transverse tubule |
| Is there direct connection between the Triad? | No. membranes are tightly bound & in close contact but no connection. |
| Why is Mitochondria and glycogen scattered among myofibrils? | breakdown of glycogen and mitochondria provide ATP needed |
| Myofilaments are made up of what 2 types of proteins? | Myosin (thick) & actin (thin) |
| What is the repeating arrangement of actin & myosin called? | sarcomere |
| What gives the sarcomere a banded appearance? | arrangement of thick and thin filaments |
| What is the smallest functional unit of the skeletal muscle fiber? | sarcomere |
| What do the interactions of myosin & actin result in? | skeletal muscle fiber contractions |
| What makes up the proteins of the center M line in the sarcomere? | mysosin (dark band) |
| What proteins make up the ends of the sarcomere of which extend toward the center M line? | Z lines |
| What is the Zone of Overlap? | thin filaments pass between thick;each thin filament sits ina triangle formed by 3 thick filaments; each thick filament is surrounded by 6 think filaments |
| Differences in the __ and __ of the thin and thick filaments account for the banded experience | size and density |
| What is the A band? | thick filaments from M line (center), the H band (thick filaments only) and the zone of overlap (both thin and thick filaments) |
| Waht does each thin filament consist of? | F actin (twisted strand) mades up of G actin molec |
| What holds the F actin together? | strand of protein nebulin |
| Each molec of __ Actin contains an active site that can bind to a thick filament. | G actin |
| What associated proteins covers the actin to prevent interaction with myosin? | tropomyosin form a long chain covering active sites |
| What holds the tropomyosin in place? | troponin |
| Before a contraction can take place what must happen to troponin? | troponin must change positions which also moves the tropomysoin molec and exposes the active sites |
| What makes up thick filaments? | bundle of myosin molec weith a head and tail |
| What direction are the Myosin molec oreinted from the M line? | away from the M line;the heads project outwards towards the ends or Z lines |
| Why are Myosin heads also known as cross bridges? | they connect thick filaments and thin filaments during a contraction |
| Each thick filament as a __ of titin | core |
| When are the titn strands completely relaxed? | normal resting sarcomere |
| When do the titin become tense? | only when some external force stretches the sarcomere |
| What helps the sarcomere return to normal resting length? | recoil of the titin |
| What is muscle tension? | contracting muscle fiber exerts a pull and shortens in length |
| What is the trigger for a contraction? | Ca ions and the presence of ATP |
| Name the 4 physical changes that occur in a muscle contraction or sliding filament theory | 1)H band & I band get smaller2)zone of overlap gets larger3)Z lines (ends) move closer together4) width of A band remains the same |
| When does sliding occur? | myosin heads of thick filaments bind to acti active sites |
| When does cross bridging occurs? | myosin head pivots towards the M line (center) pulling actin toward the center also |
| What happens after the first initial pivot of the myosin head? | cross bridge then detaches and returns to original position..repeat cycle of "attach,pivot,detach,return" |
| What determines the amount of tension in a contraction? | number of cross bridge interaction in the sarcomeres of myofibrils |
| What determines the amount of cross bridges? | degree of overlap between thin and thick filaments |
| Can all myosin heads bind to actin active sites? | no, only the myosin heads within the zone of overlap |
| The tension of a contraction is therefore related to the ____ of an individual sarcomere | structure |
| The CA ions in a sarcoplasm of a resting SM fiber is very ___ but the CA 2+ ions inside the terminal cisternae is much ____ | low; higher inside |
| Electrical events at the sarcolemma (cell membrane) cause what? | contraction by releasing CA ions from terminal cisternae |
| What distributes this electrical message or impulse? | T tubules |
| What happens to the newly released CA ions? | diffuse inmto zone of overlap of nearby sarcomeres & bind to troponin |
| What happens to troponin when CA ions bind to it? | changes the troponin shape and thus alters the position of tropomyosin, revealing the actin active sites; cross briding occurs;contraction |
| What happens if electrical stimulation stops? | SR (sacroplasmic reticulum) with re capture the CA ions and the tropomyosin will block the active sites; contraction stops |
| What actually cocks or pivots the myosin head and prepares it for binding to active site? | binding & breakdown of ATP |
| After the first initial bross bridge,does ATP need to be present again for the myosin head to detach and re-cock? | yes |
| What if there is still incoming electrical impulses but no more ATP? | contraction stops |
| muscle contraction is ___ and the return to resting length is _____ | active; resting is passive |
| What factors help a return a shortened muscle back to normal length? | 1) elastic forces like the recoil of elastic fibers in epimysium,perimysium,endomysium2)pull of other muscles3) gravity |
| What alters the transmembrane potential of the sarcolemma? | chemicals released by motor neuron at neuromuscular junction (NMJ) |
| What triggers the release of CA 2+ by the sarcoplasmic reticulum (SR)? | change in transmembrane potential of T tubules |
| What initiates the contraction? | release of CA ions by SR |
| The ___ neuron controls the skeletal muscle fiber from the CNS | motor |
| Although the body of the motor neuron is in the CNS, the axon extends out into the skeletal muscle fiber at the _____ | Neuromuscular junction of the muscle fiber |
| The ___is the tip of the axon at the NMJ | synaptic terminal |
| What does the cytoplasm of the synaptic terminal contain? | mitochondria & synaptic vesicles w/ACH |
| Acetylcholine is an example of a ____ or chemical released by a neuron to communicate with a cell | neurotransmitter |
| What actually happens to indicate the communication between the neuron and cell? | change in the transmembrane potential of that cell |
| What narrow space separates the synaptic terminal from the motor end plate of the SM fiber? | synaptic cleft |
| What enzyme is in the synaptic cleft that breaks down the ACH? | AChE (acteylcholinesterase) |
| What is the electrical impulse that sweeps into sarcolemma and T tubules of SM fiber? | action potential |
| What will stop the action potential? | acetylcholinesterase enzyme removes the bound ACH onto the receptor sites on the actin |
| What is a motor unit? | all SM fibers controlled by a single motor neuron |
| What is the indication of how precise and fine a movement can be? | size of a motor unit |
| What is an example of a motor unit that controls more than one muscle fiber? | muscles of the eye |
| How much control do we have over power generating muscles,like our legs? | less precise control since 2000 SM fibers are controlled by a single motor neuron |
| What causes the single momentary muscle twitch or contraction? | single stimulus |
| What is the smooth but steady increase in muscular tension? | recruitment or multiple motor unit summation |
| How does the nervous system provide precise control over the pull exerted by muscle? | varying the motor units activated at any time |
| What is the all or none principle? | All muscle fibers in a single motor unit contract at the same time |
| What affects the amount of force exerted by muscle as a whole? | how many motor units are activated |
| When a muscle is at rest some motor units are ____ | active |
| What is the resting tension of muscle? | muscle tone;contractions do not produce movement but tense the muscle |
| What do resting muscle tone stabilize? | position of bones and joints |
| What is monitered by sensory nerves that control muscle tone in surrounding muscle tissue? | muscle spindles |
| With exercise what happens to the muscle fibers? | 1)larger # mitochondria2) higher concentration of glycolytic enzyme3) larger glycogen reserves4) increased myofibrils (thick and thin filaments) |
| When does hypertrophy occur? | muscles that have been repeatedly stimulated to produce near-max tension |
| What happens when Sm is not stimulated by motor neurons on a regular basis? | Atrophy- reduction in muscle size,tone,power |
| Is atrophy reversible? | yes. but dying muscle fibers cannot be replaced and sometime functional losses are permanent |
| Name 3 types of skeletal muscle fibers: | 1)fast- white fibers2)slow- red fibers3)intermediate fibers |
| Why do fast fibers fatigue easily? | 1)glycogen reserves are limited and lactic acid builds up |
| How are fast fiber contractions supported? | anaerobic glycolysis (no oxygen to break down sugars into lactic acid); few mitochondria to supply ATP |
| Why do slow/red fibers take 3X as long to contract? | slow/red are specialized to contract for long periods without fatigue |
| ___ fibers have lots of mitochondria and uses aerobic break down of glycogen | slow/red, more cappilaries to deliver oxygen |
| Why are slow fibers red? | contain globular protein of red pigement (myoglobin) |
| What are the traits of Intermediate fibers? | contract faster than slow but not more than fast/white fibers; looks like fast/red fibers |
| Which muscle areas do not have slow/red fibers? | eye and hand;need fast but brief contractions |
| Which muscles are dominated by slow/red fibers & contract almost continually to maintain an upright posture | back and calf muscle |
| Wht type of fibers increase with one trains for a marathon? | intermediate; fast fibers to intermediate |
| __ fibers dominate sprinters and weight lifters | fast/white; brief periods of intense activity |
| Does endurance training promote hypertrophy? | No. only interval training (combo of weight training and cario excercise) can promote hypertrophy and improve endurance |
| What are fascicles? | muscle fibers within SM that form bundles (bouquet of flowers ) |
| What are the 6 patterns or organizations of fascicles? | "PC to converge with 1,2 multiple Pens"1. P= parallel2. C= circular3. Converge= convergent4. 1= Unipennate5. 2= Bipennate6. Multi pens= multipennate |
| Most of the skeletal muscles in the bodya re ___ | parallel |
| What is an example of a parallel muscle with a central body and cord like tendons at the ends? | biceps brachii; muscle contracts: gets shorter and body increased in diameter |
| What is an example of a circular muscle or sphincter? | orbicularis oris; guards the entrance or exit of internal passageways of the digestive and urinary tracts; muscles contract the opening closes up or gets smaller. |
| ____ muscle example is the chest or pectoralis major/minor | convergent; spread out liike a fan or broad triangle; pulls on a tendon |
| What is a raphe? | slender band of collagen fiber; convergent muscle (chest muscles) can pull on it but not as hard as a parallel muscle (biceps) |
| What is a pennate muscle? | fether like shape fibers with one or more tendons through it;pull at an angle |
| The thight or recus femoris muscle is an example of a ___ muscle | Bipennate thigh (bionic woman is a fast runner) |
| What is the FX of the Bipennate muscle or thigh? | extend the knee |
| What is the name of the feather like shape but the muscles are found on the same side as tendons? | unipennate muscle; example= extensor digitorum muscle (extends the fingers) |
| Name the 3 types of muscle primary action | 1. Prime mover (agonist)2. synergist Ihelper of agonists)3. antagonist = actions oppsoe agonist |
| What are the synergistis called when they prevent movement in a joint to stabilize origin of agonist? | fixators |
| What are the 2 muscles that do not formally include "muscle" in its name | platysma & diaphragm |
| The force,speed or direction of a movement can be modified by attaching muscle to a ____ | lever (rigid stucture like a bone ) |
| What is fulcrum? | joint (lever moves on a fixed point or fulcrum) |
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mich826
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