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Chp 9 muscles

Bio 260 brulte/ marieb/ chp 9 muscles

QuestionAnswer
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)
Created by: mich826