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338 Cards in this Set

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T or F
muscle tissues make up half of the body's mass
true
What is the most distingusihing functionial characterisic of muscles?
is thier ability to transform chemical energy into directed mechanical energy
NAME
is thier ability to transform chemical energy into directed mechanical energy
muscles
What are the three types of muscles?
(1)skeletal (2)cardiac (3)smooth
What are muscle fibers?
are skeletal and smooth muscles cells that are elongated
NAME
are skeletal and smooth muscle cells are elongated
muscle fibers
What do muscle contractions depend on?
two kingds of myofilaments
NAME
depends on two kinds of myofilaments
muscle contractions
What do the prefixes, myo, mys, or sacro, refer to?
muscle
What are the different prefixes that refer to muscles? (3)
(1)myo (2)mys (3)sacro
What is skeletal muscle tissue?
is packaged skeletal muscles
NAME
is packaged skeletal muscles
skeletal muscle tissue
What are skeletal muscles?
are organs that attach to and cover the bony skeleton
NAME
are organs that attach to and cover the bony skeleton
skeletal muscles
NAME
are the longest muscle cells
skeletal muscle fibers
NAME
these muscles have striations and can be controled voluntary
skeletal muscle fibers
Skeletal muscle fibers have (1) and can be controled (2)
(1)striations (2)voluntaru
Which muscle fiber cells are the longest?
skeletal
What are striations?
are obvious stripes on skeletal and cardiac muscle cells
NAME
are obvious stripes on skeletal and cardaic muscle cells
striations
NAME
this muscle is the only type subject to ctronolled to conscious control
skeletal muscle
NAME
these muscles are responsible for overall body mobility
skeletal muscle
What is cardiac muscle tissues?
occurs only in the heart where it constitutes the bulk of the heart walls
NAME
ocurs only in the heart where it constitutes the bulk of the heart walls
cardiac muscle tissues
NAME
this muscle is striated and is not voluntary
cardiac muscle tissues
What is smooth muscle tissues?
is found in the walls of hollow visceral organs such as the stomach, urinary bladder, and respiartory passages
NAME
is found in the walls of the hollow visceral organs such as the stomach, urinary bladder, and respiratory passages
smooth muscle tissues
NAME
this muscle has no striations and is not voluntary
smooth muscles
Do smooth muscles have striations?
no
Which muscle are the involunatry muscles?
(1)smooth (2)cardiac
what are the functions of the smooth muscles?
to force fluids and other substances through internal body channels
NAME
the role of this muscle tissue is to force fluids and other substances through internal body channels
smooth muscles
NAME
this muscle is described as being visceral, nonstriated, and involuntary
smooth muscle tissue
What are (4) functional characteristics of muscle tissue?
(1)exictibalilty (2)Contractility (3)ectensibility (4)elasticity
What is exicability?
is the ability to receive and respond to a stimulus
What is a stimulus?
is any change in a environment whether inside or outside the body
NAME
is an change in the environment whether inside or outside the body
stimulus
NAME
is the ability to receive and respond to a stimulus
exicability
What is contractility?
is the ability to shorten forcibly when adeuqatley stimualted
NAME
is the ability to shorten forcibly when adququatly streched
contractility
What is extensibility?
is the ability to be streched or extended
NAME
is the ability to be streched or extened
extensibility
What is elascticity?
is the ability of muscle fibers to recoil and resume its resting length after being stretched
NAME
is the ability of muscle fibers to recoil and resume its resting length after being stretched
elascticity
Muscle fibers (1) when contracting
shorten
What are four important functions for the muscles? (4)
(1)movement (2)maintains posture (3)stabilizes joints (4)generates heat
NAME
there main imporant functions are movement, maintains posture, stabilizes joints, and generates heat
muscles
Just about all movements of the human body and its parts are a result of a (1)
muscle contraction
NAME
these muscles are responsible for all locomotion and manipulation
skeletal muscles
Skeletal muscles are responsible for all (1) and (2)
(1)locomotion (2)manipulation
Even as muscles pull on bones to cause movments, they (1) and (2) the joints of the skeleton
stabilze and strengthen
NAME
these are also responsible for stabilze and strenghten the skeleton and joints
muscles
Muscles generate (1) are they contract
heat
Why muscles generating heat when they contract, so important?
bc the heat is important in mantaining normal body temp
NAME
is a descrete organ made up of several kinds of different tissues
skeletal muscles
In general, each muscle is served by (1), an (2), and by (3)
(1)one nerve (2)an artery (3)one or more veins
NAME
each of these, in general, has one nerve, an artery, and one or more veins
each muscle cell
Each skeletal muscle fiber is supplied w a (1) that controls its activity
nerve ending
Muscle cells also give off large amounts of (1) that must be removed throug viens if contraction is to remain efficient
metabolic wastes
individual muscle fibers are wrapped and held together by several different (1)
connective tissue sheaths
What holds indivdual muscle fibers together?
by connective tissue sheaths
What do the connective tissue sheaths do for the muscle fibers?
support each cell and reinforce the muscle as whole
What are the different connective tissue sheaths of muscle fibers? (3)
(1)endomysium (2)Perimysium and fascicles (3) epimysium
What is Endomysium?
is a fine sheath of connective tissue consisting of mostly reticular fibers that surrounds each individual muscle fiber
NAME
is a fine sheath of connective tissue consisting of mostly reticular fibers that surrounds each indivdiual muscle fibers
endomysium
What are the different connective sheaths of musle fibers in order from internal to external? (3)
(1)endomysium (2)Perimysium and fascicles (3) epimysium
What are fasicles?
resemble bundles of sticks that are groups of wrapped endomysium within each skeletal muscle
NAME
resemble bundles of sticks that are groups of wrapped endomysium within each skeletal muscle
fasicles
What are perimysium?
is a layer of fibrous connective tissue that surrounds each fascicle
NAME
is a layer of fibrous connectve tissue that surrounds each fascicle
perimysium
What is epimysium?
is an "overcoat" of dense irregular connective tissue surrounding the whole muscle
NAME
is an "overcoat" of dense irregular connective tissue surrounding the whole muscle
epimysium
T or F
all of the connective tissue sheaths are continous with one another
true
When each muscle fiber contracts, they pull on (1) which in turn (2)
(1)connective sheaths (2)transmit the pulling force to the bone to be moved
Connective sheaths also contribute to the (1) of muscle tissue
natural elasticity
Most skeletal muscles span joints and are atatched to (1) in at least two places
bones
What happens when the muscle contracts?
the muscles insertion moves toward the orgin
What are the differ muscle attachments?
(1)indirect (2)direct
Direct muscle attachments are called (1)
fleshy attachments
(1) muscle attachments are also called fleshy attachments
direct
What is a direct muscle attachment?
is when the epimysium of the muscle is fused to the periosteum of the bone or perichondrium of the cartilage
NAME
refers to when the epimysium of the muscle is fused to the periosteum of the bone or perichondrium of the cartilage
direct muscle attachment
What is an indirect muscle attachment?
is when the muscle's connective tissue wrapping's extend beyound the muscle either as a ropelike tendon or aponeurosis
NAME
refers to when the muscle's connective tissue's wrappings extend beyound the muscle either as a ropelike tendon or aponeurosis
indirect muscle attachment
What is aponeurosis?
is a sheetlike tendon that anchors the muscle to the connective tissue covering of a skeletal element
NAME
is a sheetlike tendon that anchors the muscle to the connective tissue coverings of a skeletal element
aponeurosis
(1) attachements are more common
indirect
Why are indirect attachments more common?
bc of their durabilty and small size
Tendon (1)
conserve space
Each (1) is a long cylindrical cell w multiple oval nuclei arranaged just beneath its sarcolemna surface
skeletal muscle fiber
Each skeletal muscle fiber is a long (1)w multiple oval nuclei arranged just beneath its (2)
(1)cylindrical cell (2)sarcolemna
What is sarcolemna?
is the muscle fibers of the plasma membrane
NAME
is the muscle fibers of the plasma membrane
sarcolemma
What is the sacroplasm?
are the muscle fibers of the cytoplasm
NAME
are the muscle fibers of the cyotplasm
sacroplasm
What do sacroplasm contain? (2)
(1)glycosomes (2)myoglobin
NAME
contain both glysosomes and myoglobin
sacroplasm
What is myoglobin?
is a red pigment that stores oxygen
NAME
is a red pigment that stores oxygen
myglobin
What is hemoglobin?
is a pigment that transports oxygen in the blood
NAME
is a pigment that transports oxygen in the blood
hemoglobin
Each muscle fiber contain a large number of rodlike (1) that run parellel to its length
myofibrils
What are myofibrils?
can be found in each muscle fiber and run parellel to its length
NAME
can be found in each muscle fiber and run parellel to its length
myofibrils
NAME
account for 80% of a cell's volumne
myofibrils
What are striations?
are repeating series of dark A bands and light I bands
NAME
are repeating series of dark A bands and light I bands
striations
What are I bands?
are light bands evident along each myofibirl
NAME
are light bands evident along each myofibril
I bands
What are A bands?
are dark bands evident along each myofibril
NAME
are dark bands evident along each myofibril
A bands
What is H zone?
is a light stripe on the midsection of each band
NAMe
is a light stripe on the midsection of each band
H zone
What is a M line?
is a dark line that biscets the H zone vertically
NAME
is a dark line that biscets the H zone vertically
M line
What is a Z disc?
is a darker area that is a midline interruption of a I band
NAME
is a darker area that is a midline interruption of a I band
Z disc
What is a sarcomere?
is the region of myofibril btwn two succseive discs
NAME
is a region of myofibril btwn two sussescive discs
sarcomere
What are the functional units of skeletal muscles ?
sacromeres
The banding pattern of myofibrils arises from two orderly arrangements of two structures: (1) and (2)
(1)myofilaments
What are myofilaments?
are smaller structure inside the sacromers
NAME
are smaller structures inside of sacromers
myofilaments
What are the different types of myofilaments? (2)
(1)thick (2)thin
What are thick filaments?
are myofilaments that extend the entire length of the A band
NAME
are myofilaments that extend the entire length of the A band
thick filaments
What are thin filaments?
are myofilaments that extend across the I band and partway into the A band
NAME
are myofilaments that extend across the I band and partway into the A band
thin filaments
What are Z discs composed of?
nebulin
What is nebulin?
is a protein that makes of the Z discs
NAME
is a protien that makes of the Z discs
nebulin
What makes of the thick filaments?
myosin
What is myosin?
is the protien that makes of thick filaments
NAME
are the protiens that make of thick filaments
myosin
Describe the structure of the protien myosin?
(1)has a rodlike tail and (2)terminating globular heads
The heads of myosin link the thick and thin filaments to togehter during (1)
contraction
the heads of (1) link the thick and thin filaments to together during muscle contraction
myosin
NAME PROTIEN
has two globular heads and a rodlike tail
myosin
What is the cross bridge?
is where the myosin heads link the thick and thin filaments
NAME
is where the myosin heads link the thick and thin filaments
cross bridge
Desribe the portions of the thick filament (2)?
(1) has smooth and (2)is studded with an array of myosin heads
NAME
has smooth and is studded w an array of myosin heads
thick filament
The heads of myosin are (1) and (2)
(1)actin binding site (2)ATP binding sites
NAME
these are actin binding sites and ATP binding sites
myosin
What protien makes of thick filaments?
actin
What is actin?
is a protien that makes of thick filaments
NAME
is a protien that makes of thick filaments
actin
What are the subunits of actin?
G actin
What is G actin?
bear the active sites to which the myyosin heads attach during contraction
NAME
bear the active sites to which the myosin heads attach during contraction
G actin
G actin are polymerized into long actin filaments called (1)
F actin
What is tropomyosin?
is a rod shaped protien that spirals about actin's core and help to stiffen it
NAME
is a rod shaped protien that spirals about actin's core and helps to stiffen it
tropomyosin
in a relaxed muscle, (1) they block actin's sites so that myosin heads cannot bind to thin filaments
trpomyosin
in a relxed muscle, tropomyosin (1)
block actin's sites so that myosin heads cannot bind to thin filaments
What is a troponin?
is a 3 polypeptide complex
NAME
is a 3 polypeptide complex
tropin
What are two major protiens in thin filaments? (2)
(1)tropin (2)tropomyosin
What are the three polypeptides complexes of tropin?
(1)TnI (2)Tnt (3)TnC
NAME
is made up of three polypetide chains: TnI, Tnt, and TnC
tropin
What is TnI?
is an inhibitory subunit that binds to actin
NAME
is an inhibitory subunit that binds to actin
TnI
What is TnT?
is an inhibitory subunit that binds to tropomyosin and helps to postion it on actin
NAME
is an inhibitory subunit that binds to tropomyosin and helps to position it on actin
TnT
What is TnC?
is a inhibitory subunit that binds calicum ions
NAME
is an inhibitory subunit that binds calicum ions
TnC
What is an elastic filament?
is composed of the protien titin
NAME
this filament is composed of the filament titin
elastic filament
What is titin?
makes of elastic filaments
NAME
is a protien that makes up elastic filament
titin
What are the functions of titin?
(1)holding the thick filaments in place and thus orgainazation of the A band (2)assisting the muscle cell to spring back into shape after being stretched
NAME
this protien's function include holding the thick filaments in place thus organization of the A band (2)assisting the muscle cell to spring back into shape after being stretched
titin
Skeletal muscle fibers contain two sets of (1)
intracellular tubules
What are two sets of intrcellular tubules that make up skeletal muscle fibers? (2)
(1)the SR (2) T tubules
What does SR stand for?
sacroplasmic reticulum
NAME
is elaborate smooth er
SR
What is SR?
is elaborate smooth er
NAME
the intacellular tubules of this fiber are SR and T tubules
skeletal muscle fibers
What are terminal cisternae?
are perpendicular cross channels at the A band and I band junctions
NAME
is a perpendicular cross channels at A band - I band junction
terminal cisternae
What is terminal cisternae?
is a perpendicular cross channel at A-band-I band junction
What is the major role of the SR?
is to regulate intracellular levels of ionic calicum
NAME
the major role of this is regulate the intracellular levels of ionic Ca
SR
How does the SR regulate the levels of Ca?
by it stores Calcium and releases it on demand when the muscle fiber is stimulated to contract
NAME
it stores Ca and releases it on demand when the muscle fiber is stimulated to contract
SR
(1) provides the final go for muscle contraction
Ca
Ca provides the final go for (1)
muscle contraction
NAME
an elongated tube formed by penetration of the sacromola cell at each A band-I band junction
T tubules
What are T tubules?
are elongated tubes formed by penetration of the sacromola cell at each A band-I band junction
What are triads?
are successive groupings of three membranous structures
NAME
is the succesive groupings of three membraneous structures
triads
What are the three susecvie groupings of traids?
(1)T tubules (2)2 terminal cisterna
What is muscle contraction ultimately controled by?
nerve initated electrical impulses
T tubules can be thought of as (1)
rapid telegraphy system that ensures that every myofiobril in the muscle fiber contracts virtually at the same time
NAME
these can be thought of as rapid telegraphy system that ensures that every myofiobril in the muscle fiber contracts virtually at the same time
T tubules
What is contraction?
refers to the activation of myosin's cross bridges
NAME
refers to the activation of myosin's cross bridges
contraction
How does shortening of muscle fibers ocur?
when the tension generated on the thin filaments exceeds the forces opposing shortening
NAME
ocurs when the tension generated on the thin filaments exceeds the forces opposing shortening
shortening of muscle fibers
What is plate potenital?
is a local eletrical event
NAME
is a local eletrical event
plate potential
Later, plate potenital can (1)
iginte an action potiental that spreads in all directions across the sacrolema
NAME
this can inginte an anction potential that spreads in all directions across the sarolemna
plate potenital
What is the outside face's charge of a sacrolemna ?
postive
What is the inside face's charge of a sacromlemna?
negative
What is membrane potential?
is the difference in charge
NAME
is the difference in resting potiental
membrane potential
What is the predominant extracellular ion in the sacrolemma?
Na
What is the predominant intracellular ion in the polarized sacrolemma?
k
T or F
the sacrolemma is relatively impermeable to both ions
true
How do sodium channels open up?
an axonal terminal of a motor neuron releases ACH and causes a patch of the sacrolemma to become permeable to Na+
NAME
an axonal terminal of a motor releases AcH and causes a patch of sacrolemma to become permeable to Na+
the opening of sodium channels
What is the depoliraztion ?
is when Na enters the cell and the resting poteinal is decreased
NAME
is when Na enters the cell and the resting potential is decreased
depolrization
if the stimulus is strongh enough, (1) is intiated
action potential
(1) changes the permeability of the adjacent patch
polartiy reversal of the inital patch of sacrolemma
the polarity reversal of the inital patch of sacrolemma can (1)
change the permeability of the adjacent patch
bc of the reversal of polarity causing the voltage regulated Na channels to open, the adjacent patch's (1)
depolirze
Na channels in the sacrolemma are (1)
voltage regulated
The (1) travels rapidly along the sacrolemma
action potential
The aciton potential travels rapdily along the (1)
sacrolemma
once the action potential is iniated, is it stoppable?
no
T or F
once initiated, the action potential is stoppable
False
What happens once the action potential is initiated?
the aciton potential is unstoppable and results in the contraction of a muscle
(1) results in the contraction of a muscle
the iniatiation of the action potential
Immediatly after the depolirazation wave passes, the (1)
sacrolemma permeability changes
Immediatly after the (1), the sacrolemma permeability changes
depolarization wave passes
(1)channels close and (2) channels open
(1)Na (2)K
Na channels (1), and K channels (2)
(1)open (2)close
What does K+ do as it diffuses from the cell?
restores the eletrical polarity of the scarolemma
NAME
as this ion diffuses from the cell, it restores the eletrical polarity of the scarolemma
K+
(1) diffuses from the cell
K+
Repolirzation and delporization ocur in (1) directions
same
(1) and (2) must ocur before the muscle can be stimulated again
(1)repolarization (2)depolarization
the ionic concentration of the resting state is restored by the (1)
Na K pump
How is the ionic concentration of the resting state restored?
by the Na K pump
What happens once the action potential is generated? (3)
(1)is propagated along the sacrolemma (2)travels down the T tubules (3)triggers Ca 2+ release from the terminal cisternae
NAME
once this is generated it is propagated along the sacrolemma, it travels down the T tubules, and triggers Ca2+ release from the terminal cisternae
action potential
Ca 2+ binds to (1)
troponin
(1) binds to troponin
Ca2+
What does the binding of Ca2+ to troponin cause? (2)
(1)the blocking of action potential (2)actin active binding sites to be exposed
NAME
this causes the blocking of action potential and actin active binding sites to be exposed
the binding of Ca2+ to troponin
(1) cross bridges alernately attach and detach
Myosin
Myosin cross bridges alernately (1) and (2)
(1)attach (2)detach
Thin filaments move (1)
toward the center of the sacromere
NAME
these filaments move toward the center of the sacromere
thin filaments
What powers the cycling process?
hydrolysis of ATP
the hydrolyis of ATP powers what process?
cycling
What happens once Ca2+ is removed from the cell?
tropmyosin blockage is restored and the muscle fibers relax
NAME
tropymosin is restored and the muscle fibers relax when (1)
Ca2+ is removed
When there is a low intracellular Ca2+ concentration what happens? (3)
(1)tropmyosin blocks the binding sites on actin (2)myosin cross bridges cannot attach to the binding sites on atcin (3)the relaxed state of the muscle is enforced
NAME
tropomyosin blocks the binding sites of actin, myosin cross bridges cannot attach to binding sites of actin, and the relaxed state of the muscle is reinforced. When does this ocur?
when there are low intracellular levels of Ca2+
What happens when there are high levels of intracellular Ca2+? (2)
(1)addittional Ca binds to troponin (2)Ca-activated troponin binds an additonal two Ca2+ at a separate regulatory site
NAME
when additional Ca binds to troponin and Ca-activated troponin binds an additional two Ca2+ at a separate regulatory site, (1)
Ca2+ levels are high
inactive tropinin binds two (1)
Ca2+
inactive (1) binds two Ca2+
tropinin
Ca activates (1)
troponin
Ca-activated troponin undergoes a (1)
coformational change
(1) undergoes a coformational change
Ca-activated troponin
What does the change in Ca-activated troponin cause?
moves tropomyosin away from actin's binding sites
(1) moves tropomyosin away from actin;s binding sites
when Ca-activated troponin undergoes a confomrational change
When Ca-actiavated troponin undergoes a conformational change, it moves (1)
tropomyosin away from actin's binding sites
Once tropomyosin moves away from actin's binding sites, the (1) can bind and cycle
myosin head
Once tropomyosin moves away from actin's binding sites, the myosin head can (1) and (2)
bind and cycle
What does myosin binding and cylcing permit?
permits contraction to begin
What permits contraction to begin?
myosin binding and cycling
What is contraction?
is the sliding of the thin filaments by the myosin cross bridges
NAME
is the sliding of the thin filaments by the myosin cross bridges
contraction
What are the sequential events of contraction?
(1)cross bridge formation (2)working stroke (3)cross bridge detachement (4)cocking of the myosin head
NAME
this sequential events of this process, include cross bridge formation, the working stroke, cross bridge detachment, and cocking of the myosin head
contraction
What happens when cross bridges form?
myosin cross bridge attaches to the actin filament
NAME
is when myosin cross bridge attaches to the actin filament
formation of cross bridges
What is the working power stroke?
is when the myosin head pivots and pulls actin filaments toward the M line
NAME
is when the myosin head pivots and pulls actin filaments toward the M line
the working stroke
What happens when the cross bridges dettach?
ATP attaches to the myosin head and the cross bridges deattach
NAME
ocurs when ATP attaches the myosin heads and the cross bridges deattach
deatchment of cross bridges
What is cocking of the myosin head
is when energy from the hydrolysis of ATP cocks the myosin head into a high energy state
NAME
is when energy from the hydrolysis of ATP cocks the myosin head into a high energy state
cocking of the myosin head
NAME
refers to the activation of myosin's cross bridges
contraction
contraction refers to (1)
the activation of myosin's cross bridges
When does contraction ends?
when cross bridges become inactive, the tension generated declines, and relaxation is induced
NAME
ocurs when cross bridges become inactive, the tension generated declines, and relaxations is induced
contraction ends
T or F
contraction of muscle fibers and muscles is similar
true
What are two types of muscle contraction?
(1)iosmetric contraction (2)iostonic contraction
What is a isometric contraction?
refers to inreasing muscle tension meaning the muscle does not shorten during contraction
NAME
refers to increasing muscle tension meaning the muscle does not shorten during contraction
isometric contraction
What is isotonic contraction?
refers to decreasing muscle length meaning the muscle shortens during muscle contraction
NAME
refers to decresing muscle length meaning the muscle shortens during contraction
iostonic contraction
What is a muscle unit?
is a motor neuron and all the muscle fibers it supplies
NAME
is a motor nueron and all the muscle fibers it supplies
motor unit
T or F
the number of muscle fibers can vary from four to several hundred
true
Muscles that control (1) have small motor units
fine movements
Muscles that control fine movements have (1)
small motor units
What are some fine movments?
movements of the eyes and fingers
NAME
refers to the movement of the eyes and fingers
fine movements
(1) have large motor units
large weight bearing muscles
Large weight bearing muscles have (1)
large motor units
(1) from a muscle unit are spread through the muscle
muscle fibers
muscle fibers from a muscle units are (1)
spread throughout the muscle
Contraction of a single motor unit causes (1)
weak contraction of the entire muscle
(1) causes weak contraction of the entire muscle
contraction of a single motor unit
Why does the contraction of a single motor unit cause the weak contraction of the entire muscle?
bc muscle fibers from a motor unit are spread throughout the whole muscle unit
What is a muscle twitch?
is the response of a muscle to a single breif threshold stimulus
NAME
is a response of a muscle to a single brief threshold stimulus
a muscle twitch
What are the three stages of a muscle twitch?
(1)latent period (2)period of contraction (3)period of relaxation
What is the latent period?
is the first few millisecounds after stimulation when exicitation- contraction coupling is taking place
NAME
is the first few millisecound after stimuluation coupling is taking place
latent period
What is the period of contraction?
when cross bridges actively form and the muscle shortens
NAME
is when cross bridges actively form and the muscle shortens
period of contraction
What is the period of relaxation?
is when Ca2+ is reabsorbed into the SR and muscle tension goes to zero
NAME
is when Ca2+ is reabsorbed into the SR and muscle tension goes to zero
period of relaxation
What are graded muscle responses?
are variations in the degree of muscle contraction (2)required for proper control of skeletal movement
NAME
are variations in the degree of muscle contraction
graded muscle responses
NAME
are required for proper control of the skeletal movement
graded muscle responses
How are graded muscle responses graded (2)?
(1)changing the frequency of stimulation (2)changing the strength of the stimulus
(1) are graded by changing the frequency of stimulation, and changing the strength of the stimulus
graded muscle responses
a single stimulus results in a (1)
muscle twitch
a single (1) results in a muscle twitch
stimulus
T or F
muscle does not have time to completly relax
True
A frequently delivered stimuli increases (1)
contractile force
A frequently delivered (1) increases contractile forces
stimuli
More rapidly delivered stimuli result in (1)
incomplete tenatus
(1) can result in tenatus
more rapidly delivered stimuli
If stimuli are given quickly enough, (1)
complete tenaus results
If (1), complete tenaus results
stimuli are given quickly enough
What is thershold stimulus?
the stimulus strength at which the first observable muscle contracion occurs
NAME
the stimulus strength at which the first observable muscle contraction occurs
thershold stimulus
What is beyond threhold, (1)
move contracts more virgoursaly as stimulus strength is increased
(1), move contracts more virgoursaly as stimulus strength is increased
beyond threhold
What controls the force of contraction?
is controlled by multiple motor unit summation
NAME
is controlled by multiple motor unit summation
force of contraction
NAME
brings more and more muscle fibers into play
recruitment
recruitment brings (1) and (2)
more and more muscle fibers into play
What is the staircase effect?
increased contraction in repsonse to multiple stimuli of the same strength
NAME
is the increased contraction in response to multiple stimuli of the same strength
the staircase effect
Why does muscle contraction increase? (2)
(1)there is increasing availabilty of Ca2+ in the saroplasm (2)muscle enzymes systems become more efficeint bc heat is increased as the muscle contracts
when muscle systems become more efficient because heat is increased as the muscle contracts, can cause (1)
contraction to increase
increasing availbilty of Ca2+ in the sacroplasm can cause (1)
contractions to increase