Anatomy and Physiology Chapter 10
blood capillary
N
endomysium
O
Z line
1
creatine phosphate is fastest glycolysis is the second quickest aerobic cellular respiration is the slowest
Place the following in order from the slowest speed to the quickest speed: glycolysis, creatine phosphate hydrolysis, aerobic cellular respiration
b f a d e c
Place the sequence of events resulting in skeletal muscle contraction in order a. generation of a muscle action potential b. generation of a nerve impulse c. power stroke with actin and myosin binding and release d. release of calcium ions from the sarcoplasmic reticulum e. calcium ion binding to troponin f. release of the neurotransmitter acetylcholine
striations
Q
sarcoplasm
R
terminal cisterns of the sarcoplasmic reticulum
Release of calcium from these structures triggers skeletal muscle contraction.
sarcolemma
S
calcium ions and ATP
Skeletal muscle contraction will continue to occur as long as which chemicals are available in the cytosol of the muscle fiber?
perimysium
10
muscle fiber
11
sarcolemma
12
myofibril
13
13 myosin heads 14 thick filament
13 15
filament
14
I band
2
e) all of these choices are correct
2) The different types of muscle tissue differ from each other by a) microscopic anatomy. b) location. c) type of Control. d) both microscopic anatomy and location. e) All of these choices are correct.
thin filament (actin)
3
e) production of vitamins.
3) Which of the following is NOT a major function of muscle tissue? a) moving blood throughout the body b) generating heat through contractions c) stabilizing the movement of joints d) promoting movement of body structures e) production of vitamins.
1. Ca2+ flows out of the terminal cistern and binds to the troponin 2. the troponin changes conformation (shape) which pulls the tropomyosin 3. the change in conformation (shape) reveals an active binding site on the actin 4. myosin heads bind to the actin forming cross bridges which involves the hydrolysis of ATP 5. the release of the ADP causes the power stroke
4
bone
4
thick filament (myosin)
4
M line
5
The myosin power stroke results in the thin actin fibers moving towards the M line of the sarcomere causing the muscle length to shorten.
5
periosteum
5
A band
6
tendon
6
H zone
7
epimysium
7
belly of skeletal muscle
8
endomysium
9
fascicle
A
latent period
A
thin filament made of actin
A
twitch contraction
A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as
endoysium perimysium epimysium
A tendon is formed by the merging of the which structures?
1. convert the lactic acid produced during exercise back into glycogen. 2. resynthesize creatine phosphate. 3. replace oxygen displaced from muscle myoglobin.
After prolonged strenuous exercise has stopped, heavy breathing will often continue for several minutes in order to provide the oxygen needed to do what three things?
go through cell division
After the fusion of myoblasts, the muscle fiber loses its ability to do what?
muscular hypertrophy
An increase in the production of myofibrils, mitochondria, sarcoplasmic reticulum, and other organelles that usually occurs after birth
b) calcium ions
Smooth muscle tone is maintained by the prolonged presence of _____ in the muscle cell's cytosol? a) ATP b) calcium ions c) phosphate ions d) myoglobin e) None of these choices.
Typically, the different motor units of an entire muscle are not stimulated to contract in unison. Some are contracting and others are relaxing.
Are all the motor units in an entire muscle stimulated at the same time?
filament (thick or thin)
T
most skeletal muscles have all 3 fibers and usually half are SO, but this can vary depending on a persons training regimen
Are muscles composed of only one kind of muscle fiber?
contraction period
B
thick filament made of myosin
B
tropomyosin
B
Zone of overlap
The area covered by 6 minus the area covered by 5
myofibrils
The contractile organelles of a skeletal muscle fiber are thread-like structures called
dense bodies that are dispersed throughout the sarcoplasm some directly attach to the sarcolemma
There are no z discs in smooth muscle fibers. What do the filaments attach to?
slow oxidative fiber
This is the least powerful type of skeletal muscle fiber.
epimysium
This is the outermost layer of connective tissue surrounding a skeletal muscle.
synaptic cleft
To stimulate skeletal muscle contraction, acetylcholine must cross the _____ of the neuromuscular junction and bind to receptors on the motor endplate.
1. electrical excitability 2. contractility 3. extensity 4. elasticity
What are the four properties of muscular tissue?
hormones and neurotransmitters adjust heart rate by speeding or slowing the pacemaker
What can cause the heart rate to change and how does it affect the heart
1. it provides a way for nerve, blood, lymph to get the muscle. 2. triglycerides insulate and protect the muscle
What does the subcutaneous layer do for the muscles?
ATP hydrolysis reaction
What energizes the myosin head?
Calcium ions are continually released even though the calcium ions in the sarcoplasm are still elevated
What is happening in the sarcoplasm that is responsible for tetanus?
subcutaneous layer areolar and adipose
What layer separates muscle from skin? What type of tissue is that layer composed of?
From the M line to Z disc
What regions of a sarcomere contain titan?
tropomyosin and troponin
What regulatory proteins can be found in the thin filaments of skeletal muscle fibers?
epimysium
What structure holds muscles with similar functions together, allows free movement of muscles, carries nerves, blood vessels and lymphatic vessels, and fills spaces between muscles?
skeletal muscle fiber - acetylcholine released by somatic motor neurons cardiac muscle fiber - acetylcholine and norepinephrine released by autonomic motor neurons AND hormones smooth muscle fiber - acetylcholine and norepinephrine released by autonomic motor neurons AND hormones AND stretching AND local chemical changes
What things regulate the contraction of skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?
aponeurosis
What type of tendon is formed when the connective tissue elements of a skeletal muscle extend as a broad flat layer?
tension force
When a skeletal muscle contracts, it generates ________ while pulling on its attachment points. (force of contraction)
4
Which area of the myogram shows a sustained contraction where individual twitches are indiscernible?
2
Which area of the myogram shows sustained contraction with partial relaxation?
muscular atrophy
Which disorders is characterized by the wasting away of muscles due to the progressive loss of myofibrils?
c eccentric contraction
Which figure exhibits a contraction of the biceps brachii muscle in which its length increases? what is this called?
b
Which figure exhibits concentric contraction of the biceps brachii muscle?
a
Which figure exhibits isometric contraction of the biceps brachii muscle?
d) deepening of the voice
Which is a NOT a side-effect of anabolic steroid use by male athletes? a) sterility b) baldness c) diminished testosterone secretion d) deepening of the voice e) atrophy of testes
e) high amount of glycogen in the sarcoplasm
Which of following is a common characteristic of fast skeletal muscle fibers? a) large amount of myoglobin. b) many mitochondria. c) low concentration of creatine kinase in the sarcoplasm. d) slow myosin ATPase. e) high amount of glycogen in the sarcoplasm.
b) motor unit
Which of the following consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates? a) sarcomere b) motor unit c) neuromuscular junction d) muscle unit e) multi-unit smooth muscle
d) axon of neuron, sarcolemma, T tubules
Which of the following correctly lists the sequence of structures that action potentials must move through to excite skeletal muscle contraction? a) sarcolemma, axon of neuron, T tubules b) T tubules, sarcolemma, myofilament c) muscle fiber, axon of neuron, myofibrils d) axon of neuron, sarcolemma, T tubules e) myofibrils, myofilaments, mitochondria
b) limited, under certain conditions
Which of the following describe the regeneration capacity of cardiac muscle cells? a) limited, via satellite cells b) limited, under certain conditions c) considerable (compared with other muscle cells, but limited compared with epithelium), via pericytes d) all of these are correct e) none of these are correct
b. myosin
Which of the following functions as a motor protein in all three types of muscle tissue? a) actin b) myosin c) troponin d) titan e) tropomyosin
e) all of these are correct
Which of the following is a common effect of aging on skeletal muscle? a) loss of muscle mass b) decrease in maximal strength c) a slowing of muscle reflexes d) loss of flexibility e) all of these are correct
e
Which of the following is not true concerning sarcomeres (before contraction begins) and the muscle fiber length-tension relationships a. if sarcomeres are stretched, the tension in the fiber decreases b. if a muscle cell is stretched so that there is no overlap of the filaments, no tension is generated c. extremely compressed sarcomeres result in less muscle tension d. maximum tension occurs when the zone of overlap between a thick and thin filament extends from the edge of the H zone to one end of a thick filament e. if sarcomeres shorten, the tension in them increases
d) Lactic acid is continually produced
Which of the following statements does NOT accurately describe aerobic cellular respiration in skeletal muscles? a) Pyruvic acid generated by glycolysis enters the mitochondria. b) O2 is essential. c) CO2 is produced as a waste product. d) Lactic acid is continually produced. e) Can be used to generate ATP from fats, proteins or carbohydrates.
tendon
Which of the following structures are made of dense regular connective tissue?
e) cramp
Which of the following types of abnormal contractions of skeletal muscle may be caused by holding a position for a prolonged period? a) spasm b) fasciculation c) tremor d) fibrillation e) cramp
a) cardiac muscle
Which of the following types of muscle tissue contract when excited by their own autorhythmic muscle fibers? a) cardiac muscle b) slow twitch oxidative skeletal muscle c) multi-unit smooth muscle d) fast twitch glycolytic skeletal muscle e) All of these choices are correct.
both I band and A band
Which of the regions of a sarcomere contain thin filaments?
A band, H band, and the zone of overlap
Which of the regions of the sarcomere contain thick filaments?
refractory period
Which period is referred to as the period of lost excitability in skeletal muscle fibers?
1
Which portion of this myogram shows a single twitch of the muscle?
d) all of these choices are correct
Which processes are commonly used to produce ATP during skeletal muscle contraction? a) creatine phosphate b) anaerobic cellular respiration c) aerobic cellular respiration d) All of these choices are correct. e) None of these choices are correct.
extensibility
Which property of muscle gives it the ability to stretch without damage?
dystrophin
Which proteins are used to reinforce the sarcolemma and to help transmit the tension generated by the sarcomeres to the tendons?
single-unit smooth muscle fibers
Which type of muscle tissue is capable of undergoing the stress-relaxation response when they are stretched?
I band
Z discs pass through the center of which band?
sarcolemma
a
somatic motor neuron axon terminal buton (bulb)
a
twitch contraction
a brief contraction of all the muscle fiber in a motor unit of a muscle in response to a single action potential in its motor neuron
fibromyalgia
a chronic, painful, nonarticular rheumatic disorder that affects he fibrous connective tissue components of muscles and ligaments
tendon
a cord of dense regular connective tissue that attaches muscle to the periosteum of a bone
fascia
a dense sheet of connective tissue that lines the body wall and binds muscles with similar functions together.
sarcoplasmic reticulum
a fluid-filled system of membranous sacs that encircle every myofibril
fasicles
a group of 10 to 100 muscle fibers surrounded by perimysium
Z disc
a narrow, plate-shaped region of dense protein that separates one sarcomere from the next
cramp
a painful spasmodic contraction
calmodulin
a regulatory protein that binds calcium in the cytosol of a smooth muscle cell
tremor
a rhythmic, involuntary, purposeless contraction that produces a quivering or shaking movement
anaerobic cellular respiration glucose is catabolized to generate ATP glycogen is catabolized to generate glucose
a series of ATP-producing reactions that do not require oxygen What molecules are used?
endomysium
a sheath of areolar connective tissue that wraps around individual skeletal muscle fibers
motor unit
a single somatic motor neuron and all the muscle fibers it stimulates
muscle tone
a small amount of tautness or tension in the muscle due to weak, involuntary contractions of its motor units
stress-relaxation response
a smooth muscle phenomenon where smooth muscle fibers are stretched and it results in an initial contraction which increasing the tension but then in a minute or two it relaxes
tic
a spasmodic twitching made involuntarily by muscles that are ordinarily under voluntary control
fibrillation
a spontaneous contraction f a single muscle fiber that is not visible under the skin but can be recorded by electromyography
smooth muscle tone
a state of continued partial contraction
flaccid
a state of limpness in which muscle tone is lost
spasm
a sudden involuntary contraction of a single muscle in a large group of muscles
triad
a transverse tubule and the two terminal cisterns on either side of it
neuromuscular disease
abnormality of skeletal muscle function due to disease or damage of any part of a motor unit
satellite cells divide slowly and fuse with existing fibers to assist both in muscle growth and repair
after birth, how is muscle repair accomplished?
mesoderm
all muscles of the body are derived from this embryonic tissue
striations
alternating light and dark bands on muscle tissue
recovery oxygen uptake
amount of oxygen needed to restore the body's metabolic conditions back to resting levels after exercise
myasthnia gravis
an autoimmune disease that causes chronic, progressive damage of the neuromuscular junction
myosin light chain kinase
an enzyme in the cytosol of a smooth muscle cell that takes a phosphate from calmodulin and attaches it to the head of the myosin, enabling the head to attach to the actin
muscular hyperplasia
an increase in the number of muscle fibers, usually during embryonic development
fasciculation
an involuntary, brief twitch of an entire motor unit that is visible under the skin and is not associated with movement of the affected muscle
30 - 40 seconds of maximal muscle activity
anaerobic cellular respiration can provide enough energy for how many seconds of maximal muscle activity?
the weakest motor units are stimulated first
are the weaker or stronger motor units stimulated first?
I band
area in the sarcomere where only thin filaments are present but thick filaments are not
H zone
area of only thick filaments
subcutaneous layer
areolar and adipose connective tissue that separates muscle from skin
myofibril triad
b
sarcolemma
b
auto rhythmicity
built in rhythm
fascicles
bundles of muscle fibers
myofirbril
c
transverse tubule
c
calsequestrin
calcium binding proteins
rigor mortis
calcium ion leakage in a cadaver result in myosin to create cross bridges but no ATP is available to cause the myosin to release
M line
composed of supporting proteins holding thick filaments together at the H zone
aponeurosis
connective tissue elements extended as a broad, flat layer
myosin and actin
contractile motor proteins
actin
contractile protein that contains myosin-binding sites
sarcomere
contracting unit of a skeletal muscle fiber
eccentric isotonic contraction
contraction in which a muscle lengthens
isometric contraction
contraction in which muscle tension is generated without shortening the muscle
concentric isotonic contraction
contraction in which the muscle shortens
sarcoplasm
cytoplasm of a muscle fiber
sarcoplasm
cytoplasm of the muscle fiber
terminal cistern of the sarcoplasmic reticulum
d
sarcoplasm
d - substance in the spaces shown
A band the band is the entire length of the thick filaments
darker middle part of the sarcomere this is the length of what structure?
hypotonia
decreased or lost muscle tone
fascia
dense irregular connective tissue that lines the body wall and limbs and holds functional muscle units together
perimysium
dense irregular connective tissue that separates a muscle into groups of individual muscle fibers
perimysium
dense irregular tissue that surrounds groups of 10 to 100 muscle fibers
1. largest in diameter with the most myofibrils 2. most powerful 3. white muscle fibers 4. fastest contraction cycle 5. quickest to reach peak tension 6. fatigue quickly 7. anaerobic glycolysis (they have lots of stored glycogen)
describe fast glycolytic fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used
1. intermediate in diameter 2. medium in power 3. red muscle fibers 4. contraction cycle 3 - 5 times factor than SO fibers 5. reach peak tension more quickly, but shorter in duration than the SO fibers 6. moderately high resistance to fatigue 7. aerobic cellular respiration and anaerobic glycolysis
describe fast oxidative-glycolytic fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used
1. smallest in diameter 2. least powerful 3. red muscle fibers 4. slower contraction cycle 5. longer to reach peak tension 6. very resistant to fatigue 7. uses most aerobic cellular respiration to make ATP
describe slow oxidative fibers 1. diameter 2. power generated 3. color 4. contraction cycle speed 5. time to peak tension 6. stamina 7. major ATP production used
it rotates as a corkscrew turn, twisting in a helix
describe the movement of the smooth muscle fiber as it contracts
terminal cisterns
dilated ends of sarcoplasmic reticulum
myopathy
disease or disorder of the muscle cell itself
skeletal muscle fiber - no cardiac muscle fiber - yes smooth muscle fiber - yes
do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have autorhythmicity?
skeletal muscle fiber - yes cardiac muscle fiber - yes smooth muscle fiber - no
do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have sarcomeres?
skeletal muscle fiber - abundant cardiac muscle fiber - some smooth muscle fiber - very little
do skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber have sarcoplasmic reticulum?
skeletal muscle fiber - none cardiac muscle - intercalated discs contain gap junctions and desmosomes visceral smooth muscle - gap junctions multiunit smooth muscle - none
do skeletal muscle fiber, cardiac muscle, visceral smooth muscle, and multiunit smooth muscle have junctions?
contracted, because the zone of overlap is wide and the H zone is narrow
do you think this myofibril is contracted or relaxed? Why?
eccentric isotonic contractions like walking downhill produce more muscle damage and more delayed-onset muscle soreness than do concentric isotonic contractions
does concentric or eccentric isotonic contraction produce more muscle damage and soreness?
every action potential has the same size in a somatic motor neuron or a muscle fiber
does the strength of action potentials vary?
actin thin filament
e
sarcoplasmic reticulum
e
muscle action potentials
electrical signals in a muscle
when a second stimulus occurs after the refractory period of the the first stimulus is over, but before the skeletal muscle fiber has relaxed, the second contraction will actually be stronger than the first.
explain wave summation
myosin thick filament
f
transverse tubule
f
central fatigue
feeling of tiredness and the desire to cease activity
tension
force of contraction
hypertrophy
growth by enlargement of the muscle cells
hyperplasia
growth by increase in the number of muscle cells
anabolic steroids
hormones that increase muscle size by increasing the synthesis of proteins in muscles and thus increasing strength during athletic contests
Muscle fibers switch from using low levels of ATP when relaxed to requiring large amounts of ATP when contracting. Most other cells have a constant amount of ATP usage.
how are the energy requirements different for muscle cells than for the majority of the other cells
the muscle filaments are not arranged in orderly sarcomeres and there is no regular pattern of overlap like in the striated muscle there are also intermediate filaments in addition to the thick and tin filaments
how are the filament arrangements in smooth muscle different than those in striated muscles?
cardiac muscle does not have an epimysium
how are the tissue layers in cardiac muscle tissues different than the tissue layers in skeletal muscle tissues?
increase the size of the muscle fibers
how do growth hormones and sex hormones affect muscle cells?
elastic components are not given time to spring back between contractions, and thus remain taut. Therefore, they do not need to stretch much before the next contraction
how do the elastic components add to the effect of tetanus?
the number and size of mitochondria is much greater in cardiac muscle aerobic cellular respiration is the primary source of ATP in a cardiac muscle fiber making the heart dependent on oxygen
how do the number and size of mitochondria in cardiac muscle compare to skeletal muscle mitochondria? what does this tell you about the cardiac muscle fibers?
creatine kinase transfers a high energy phosphate from ATP to creatine
how i creatine phosphate created?
cardiac muscle remains contracted 10 to 15 times longer than skeletal muscle Calcium ions enter the sarcoplasm from the interstitial fluid through channels as well as from the sarcoplasmic reticulum allowing for longer contraction
how is the contraction time in cardiac muscle different than the contraction time in skeletal muscle? what accounts for this?
2 ATP
how many ATP are produced by glycolysis?
larynx 2 - 3 muscle fibers per motor unit eye muscles 10 - 20 muscle fibers per unit biceps brachii in the arm 2,000 - 3,0000 muscle fibers per unit
how many muscle fibers per unit are in the following muscles: larynx eye muscles biceps brachii
one
how many possible neuromuscular junctions are possible for a single skeletal muscle fiber?
an average of 150
how many possible neuromuscular junctions are possible for a single somatic motor neuron axon?
75 times per minute
how often does cardiac muscle tissue contract when the body is at rest?
aerobic cellular respiration
in marathons, almost 100% of the ATP is produced by this method
smooth muscle fibers
in this type of muscle fiber, contraction begins slowly but lasts for long periods
smooth muscle
in this type of muscle fiber, thick and thin filaments are not arranged as orderly sarcomeres
muscle fatigue
inability of a muscle to maintain its strength of contraction or tension during prolonged activity
spasticity
increased in muscle tone associated with an increase in tendon reflexes
hypertonia
increased muscle tone
rigidity
increased muscle tone in which reflexes are not affected causing stiffness and spasms
endomysium
individual muscle fibers are covered by this layer.
muscular dystrophy
inherited muscle-destroying disease that causes progressive degeneration of the skeletal muscle fibers
transverse tubules
invaginations of the sarcolemma from the surface toward the center of the muscle fiber
wave summation
larger contractions resulting from stimuli arriving at different times
I band the band is the length of the thin filaments that do NOT lie in between the thick filaments (subtract the zone of overlap)
lighter, less dense area on the ends of the sarcomere this is the length of what structure?
neuromuscular junction (NMJ)
location where neuron action potentials are converted to muscle action potentials
flaccid paralysis
loss of muscle tone, tendon reflexes, and atrophy/degeneration of muscles due to nervous system and electrolyte disruptions
A band
middle area in the sarcomere where thick and thin filaments are found
muscle fiber
muscle cell
a few seconds
muscle cells have enough ATP stored within them to last only __________________.
concentric isotonic contraction
muscle contraction in which the tension generated is great enough to overcome the resistance of the object to be moved, the muscle shortens and pulls on a tendon, producing movement and decreasing the angle of a joint
isotonic contraction
muscle contraction in which the tension in the muscle remains almost constant while the muscle changes its length
satellite cells
myoblasts that persist in mature skeletal muscle
satellite cells
myoblasts that persist in skeletal muscle fibers after they have fused
titin alpha-actinin myomesin nebulin dystrophin
name the five structural proteins found in a myofibril.
myosin and actin
name the two contractile proteins
H zone the band is the length of the thick filaments that do NOT lie between thin filaments (subtract the zone of overlap)
narrow zone in the center of each A band this is the length of what structure?
the frequency of stimulation
number of action potential impulses per second
myoglobin
oxygen storing protein only found in muscle
myoglobin
oxygen-binding protein found only in muscle fibers
spastic paralysis
partial paralysis in which the muscle exhibits an increase in muscle tone due to nervous system and electrolyte disruptions
sarcolemma
plasma membrane of a muscle fiber
motor unit recruitment
process of increasing the number of activated motor units
M line
region in the center of the H zone that contains proteins that hold thick filaments together at the center of the sarcomere
tropomyosin
regulatory protein that blocks myosin-binding sites
more ATP creatine phosphate
resting muscle cells create _____________ than they use. Most of this is stored as ______________.
endomysium
reticular tissue that penetrates the fascicle and separates individual muscle fibers from one another
Z disc
separates the sarcomeres from each other
red muscle fibers
skeletal muscle cells with a high myoglobin content, many capillaries, and many mitochondria
white muscle fibers
skeletal muscle cells with a low myoglobin content, low number of capillaries, and smaller number of mitochondria
pericytes
stem cells capable of differentiating into smooth muscle cells
1. Nerve impulse arrives at the axon terminal 2. Ca2+ ion channels open 3. Ca2+ flows into cell 4. triggers release of acetylcholine (ACh) by vesicles into the synaptic cleft
step 1
1. ACh binds to receptors in the motor plate junctional folds causing Na+ to flow into the cell 2. the change in gradient triggers a muscle action potential that travels along the sarcolemma
step 2
1. the action potential travels to the terminal tubule 2. the changes in the terminal tubule causes the two terminal cistern in the triad to release Ca2+ ions into the myofiber (muscle cell)
step 3
fused (complete) tetanus
sustained contraction of a muscle, with no relaxation between stimuli
unfused (incomplete) tetanus
sustained, but wavering contraction with partial relaxation between stimuli
neuromuscular junction
synapse between a motor neuron and a muscle fiber
contractility
the ability to contract forcefully when stimulated by an action potential
electrical excitability
the ability to respond to certain stimuli by producing electrical signals
elasticity
the ability to return to its original length and shape after contraction or extension
extensibility
the ability to stretch within limits without being damaged
oxygen debt
the added oxygen, over and above the resting oxygen consumption, that is taken into the body after exercise
sarcomere
the basic functional unit of a myofibril
glycolysis
the breakdown of glucose to two molecules of pyretic acid
cardiac muscle fibers
the contractile cells of the heart
aponeurosis
the epimysium, perimysium, and endomysium together form this broad, flat, sheet extending beyond the muscle
tendon
the epimysium, perimysium, and endomysium together form this rope-like extension extending beyond the muscle
excitation-contraction coupling
the events where action potentials are linked to muscle contraction are called
muscle fatigue
the inability of a muscle to maintain force of contraction after prolonged activity
calsequestrin
the molecule that attaches to Ca2+ in the sarcoplasmic reticulum that allows for increasing storage of ions in the terminal cistern
epimysium
the outermost connective tissue layer that encircles an entire skeletal muscle
epimysium
the outermost layer of dense, irregular connective tissue that encircles the entire muscle
sarcolemma
the plasma membrane of the skeletal muscle cell
cardiac muscle tissue
the principle muscle tissue in the heart wall
motor unit recruitment
the process in which the number of active motor units increase
strength training
the process of exercising with progressively heavier resistance for the purpose of strengthening the musculoskeletal system
stress-relaxation response
the smooth muscle action that allows the fibers to maintain their contractile function, even when stretched
acetylcholine
the synaptic end bulbs of the somatic motor neurons contain synaptic vesicles filled with the neurotransmitter ___________.
eccentric isotonic contraction
the tension exerted by the muscle fiber resists the movement of a load and slows the lengthening process
isometric contraction
the tension generated by this type of contraction is not enough to exceed the resistance of the object to be moved, and the muscle does not change its length
muscular atrophy fibrosis
the wasting away of muscle due to lack of use is known as __________ while the replacement of skeletal muscle fibers with scar tissue is known as ___________.
Damaged muscle undergoes fibrosis, the replacement of muscle fiber with fibrous scar tissue
there is a limited number of satellite cells and this means only a small amount of muscle can be repaired. What happens with the rest of damaged muscle?
myogram
these diagrams are all what kind of graph?
mitochondria
these organelles are in large amounts in the muscle fiber and lie close to the contractile filaments
muscle tone
this type of contraction is produced by the continual involuntary activation of a small number of skeletal muscle motor units; results in firmness in skeletal muscle
cardiac muscle fiber and smooth muscle fiber
this type of muscle fiber can be autorhythmic
smooth muscle fiber
this type of muscle fiber can be classified as a single-unit or multi-unit
skeletal fiber
this type of muscle fiber does not exhibit autorhythmicity
cardiac muscle fiber
this type of muscle fiber has an extended contraction due to prolonged calcium delivery from both the sarcoplasmic reticulum and the interstitial fluid
cardiac muscle
this type of muscle fiber has fibers joined by intercalated discs
skeletal and cardiac muscle fibers
this type of muscle fiber is striated
smooth muscle fiber
this type of muscle fiber uses pericytes to repair damaged muscle fibers
skeletal and cardiac muscle fibers
this type of muscle fiber uses troponin as a regulatory protein
smooth muscle fiber
this type of muscle fiber uses calmodulin as a regulatory protein
skeletal muscle fiber
this type of muscle fiber uses satellite cells to repair damaged muscle fibers
delayed onset muscle soreness
this type of problem involves the swelling and stiffness resulting from increase in muscle protein synthesis, increased blood supply, and increased creation kinase production after strenuous exercise
exercised induced muscle damage
this type of problem involves torn sarcolemmas, damaged myofibrils, and disrupted Z disc
tranverse tubule (T tubule)
tiny invaginations of the sarcolemma that form tunnels towards the center of the muscle fiber
myofibril
tiny threadlike contractile organelles in the muscle fiber cells
true
true or false the ability of muscle cells to respond to stimuli and produce electrical signals is known as excitability
tendon sheath (synovial sheath)
two-layer tube of fibrous connective tissue enclosing certain tendons
titin
very large intersarcoplasmic protein that gives elasticity to the sarcomere
gap junctions
visceral (single unit) smooth muscle tissue uses what kind of junctions?
muscular atrophy
wasting away of muscles
disuse atrophy
wasting away of muscles due to inactivity
denervation atrophy
wasting away of muscles due to severing the nerve supply
calcium diffuses slowly into and out of a smooth muscle fiber this is necessary for places like the walls of arteries or parts of the digestive tracts where a constant, steady pressure is necessary
what accounts for the ability of smooth muscle to maintain smooth muscle tone? why would this ability be important for smooth muscles?
hypertrophy of the FG fibers and an increase in the synthesis of muscle proteins (the number of muscle cells does not increase)
what accounts for the large size and mass of muscles of body builders?
mesodermal stem cells become myoblast
what are the embryonic cells that differentiates into a mature skeletal fiber?
ATP carbon dioxide heat
what are the final products of aerobic cellular respiration?
1. producing body movements 2. stabilizing body position 3. storing and moving substances within the body 4. generating heat
what are the four functions of muscular tissue
skeletal muscle fiber - troponin and tropomyosin cardiac muscle fiber - troponin and tropomyosin smooth muscle fiber - calmodulin and myosin light chain kinase
what are the regulatory proteins in skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?
skeletal muscle fiber - fast cardiac muscle fiber - moderate smooth muscle fiber - slow
what are the speeds of contraction for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?
1. creatine phosphate 2. anaerobic cellular respiration 3. aerobic cellular respiration
what are the three methods a muscle fiber can use to generate ATP?
slow oxidative fibers fast oxidative-glycolytic fibers fast glycolytic fibers
what are the three types of muscle cells based on the speed of the hydrolysis of ATP by the myosin heads
skeletal smooth cardiac
what are the three types of muscle tissue?
1. convert lactic acid back into glycogen stores in the liver 2. resynthesize creatine phosphate 3. replace oxygen removed from myoglobin
what are the three uses for the oxygen that is taken back up after exercise has ceased?
1. contraction in a smooth muscle fiber starts more slowly and lasts longer than skeletal contraction 2. smooth muscle can both shorten and stretch to a greater extent than the other muscle types
what are the two differences in contraction in a smooth muscle compared to a skeletal muscle?
autorhythmic electrical signals chemical stimuli - neurotransmitters, hormones, change in pH
what are the two main types of stimuli that can stimulate an muscle action potential
tropomyosin and troponin
what are the two regulatory proteins found in a myofibril?
1. oxygen that diffuses into muscle from the blood 2. oxygen that is released by myoglobin within muscle fibers
what are the two sources of oxygen for a muscle cell?
isotonic contraction isometric contraction
what are the two types of contraction?
concentric isotonic contraction eccentric isotonic contraction
what are the two types of isotonic contraction?
visceral (single unit) smooth muscle tissue multi-unit smooth muscle tissue
what are the two types of smooth muscle tissue?
glycogen
what carbohydrate is found in large concentrations in the sarcoplasm?
irregular transverse thickening of the sarcolemma that connect the ends of cardiac muscle fibers to one another
what creates the intercalated discs in heart muscle?
the percentage of SO and FG fibers is genetically determined and might account for the differences in activities preferred by different people exercise can also cause the transformation of one kind of fiber to another
what determines the ratio of SO and FG fibers for a person's muscles?
links thin filaments of the sarcomere to the integral membrane proteins of the sarcolemma, which are attached to proteins in the connective tissue extracellular matrix that surrounds the muscle fibers.
what does dystrophin do for a muscle fiber?
1. amount of stretch before contraction 2. oxygen availability 3. number of muscle fibers contracting in unison 4. frequency of stimulation
what four things affect the strength of a muscle contraction?
pyruvic acid is converted into lactic acid which diffuses out into the blood
what happens to the products of glycolysis if there i no oxygen available?
Na+
what ion enters the sarcoplasm when the acetylcholine attaches to the receptors in the motor end plate junctional folds?
Ca2+
what ion enters through a voltage gated channel when the action potential arrives at the terminal buton
a somatic motor neuron and all of the muscle fibers it stimulates
what is a motor unit?
satellite cells retain the capacity to fuse with one another or damaged muscle to repair tissue.
what is special about the satellite cells in a muscle?
multiunit smooth muscle tissue consists of individual fibers each with its own motor neuron terminal and few gap junctions visceral (single unit) smooth muscle tissue consists of numerous fibers connected to each other through gap junctions with a single neuron synapsing with several of the fibers. Some of the fibers do not have neuromuscular junctions
what is the difference between the enervation and junctions found in visceral (single unit) smooth muscle and multiunit smooth muscle tissue?
acetylcholinesterase AChE
what is the enzyme that degrades acetylcholine in the synaptic cleft?
posture endurance-type activities like a marathon
what is the function of slow oxidative fibers?
anything that requires great strength for short times, like weight lifting
what is the function of the fast glycolytic fibers?
activities like walking and sprinting
what is the function of the fast oxidative-glycolytic fibers?
acetylcholine
what is the neurotransmitter used at the neuromuscular junction?
diameter 10 - 100 micrometers length 10 centimeters (4 inch) - 30 centimeters
what is the size of a mature skeletal muscle fiber (cell)?
8 nm and 1 - 2 micrometers long 16 nm and 1 - 2 micrometers long
what is the size of the thin actin filaments? what is the size of the thick myosin filaments?
desmosomes and gap junctions
what kind of junctions can be found in the intercalated discs in the heart muscle?
auto-rhythmicity
what kind of stimulation is used in visceral (single unit) smooth muscle tissue?
pyruvic acid
what molecule is used for aerobic cellular respiration?
ACT must bind again to the myosin head for it to release
what must happen to cause the myosin to break its cross-bridge to actin?
it is very elastic and can stretch to 4 times its length
what property of titan makes it useful for connecting the z disc to the M line
caveolae these are pouchlike invaginations of the plasma membrane that store calcium ions
what replaces transverse tubules and terminal cisternae in smooth muscles?
transverse T tubules
what structure spreads the muscle action potential throughout the muscle fiber
the autonomic nervous system
what subdivision of the nervous system controls the involuntary muscle
contractile protein structural protein regulatory protein
what three types of protein are used in the construction of a myofibril?
connective tissue
what tissue within the muscle limits the range of extensibility?
The H band and the zone of overlap
what two areas are in the A band?
facilitated diffusion
what type of transport is used to get glucose into the muscle cells?
the myosin heads would be unable to detach from the actin
what would happen if ATP were suddenly unavailable after the sarcomere had begun to shorten
refractory period
when a muscle fiber receives enough stimulation to contract, it temporarily loses its excitability. What is the name for this period of lost excitability?
unfused tetanus
when a skeletal muscle fiber is stimulated at a rate of 20 to 30 times per second and can only partially relax between stimuli
fused (complete) tetanus 5 - 10 times stronger
when a skeletal muscle fiber is stimulated at a rate of 80 to 100 times per second and it does not relax at all. Individual twitches cannot be detected How much stronger is this than a single twitch?
it makes up the protein in the z discs it binds the thin filaments
where can you find alpha actinin in the myofibril? what is its function?
most of the heart wall
where can you find cardiac muscle
walls of large arteries airways to the lungs arrector pili iris ciliary body of the eye
where can you find multiunit smooth muscle tissue?
muscles in the heart and muscles in the gastrointestinal tract
where can you find muscles that have autorhythmicity
wrapped around the entire length of each thin filament it anchors the thin filaments to Z discs
where can you find nebulin in the myofibril? What is its function?
it makes up the m line myosin binds to titn and connects adjacent filaments to one another myosin also holds the thick filaments together at the M line
where can you find the myosin in the myofibril? what is its function?
walls of hollow internal structures and most organs in the abdominopelvic cavity
where do you find smooth muscle in the human body
skin, walls of small arteries and veins, walls of hollow organs
where do you find visceral (single unit) smooth muscle tissue?
mitochondria
where does aerobic cellular respiration occur?
in the cytosol
where does glycolysis take place?
creatine is synthesized in the liver, kidneys, pancreas
where is creatine synthesized?
skeletal muscle fiber - sarcoplasmic reticulum cardiac muscle fiber - sarcoplasmic reticulum and interstitial fluid smooth muscle fiber - sarcoplasmic reticulum and interstitial fluid
where is the source of calcium for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?
thin filaments
which filaments are attached to the z discs?
creatine phosphate is 3 - 6 times more plentiful than ATP in resting muscle cell
which is more prevalent in a resting muscle cell, creatine phosphate or ATP?
acetylcholine
which of the following are not sources of ATP for muscle contraction? creatine phosphate glycolysis anaerobic cellular respiration aerobic cellular respiration acetylcholine
hyperplasia
which type of muscle growth primarily occurs in an embryo?
smooth muscle, especially in your digestive tract
which type of muscle tissue undergoes the greatest amount extension?
smooth muscular tissue
which type of muscular tissue has the highest capacity for regeneration?
skeletal muscle fiber - somatic nervous system (voluntary) cardiac muscle fiber - autonomic nervous system (involuntary) smooth muscle fiber - autonomic nervous system (involuntary)
which type of nervous system controls skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber?
oxygen is used for more than just the ATP pathways because of the increased temperature and increased blood pressure, tissue repair, and other factors
why do some people prefer the term recovery oxygen uptake to oxygen debt?
it has a huge size - 50 times larger than average protein It connects the Z disc to the M line of the sarcomere, allows the sarcomere to return to its original length, and keeps the A line in its position
why is titan protein named "titan?" what is the function of the titan protein?
relaxation period
C
troponin
C
z line
C
sarcoplasmic reticulum
Calcium ion storing tubular system similar to the smooth endoplasmic reticulum
a) at the beginning of a contraction
Calcium ions are released from the sarcoplasmic reticulum into the cytosol a) at the beginning of a contraction. b) in response to acetylcholine binding to Ca2+ release channels. c) by active transport using Ca2+ pumps in the SR membrane. d) after the contraction ends. e) All of these answers are correct.
skeletal muscle fiber - very large cardiac muscle fiber - large smooth muscle fiber - small
Compare the diameter of the muscle fibers in smooth, cardiac, and skeletal muscle tissue.
myosin head actin binding site
Cross bridges are formed during muscle contraction when _____ on the thick filaments binds to _____ on the thin filaments.
sarcomere
D
the actin binding site
D (the yellow dot)
Inadequate release of calcium ions from the SR, resulting in a decline of Ca2+ concentration in the sarcoplasm. Depletion of creatine phosphate also is associated with fatigue. Other factors that contribute to muscle fatigue include insufficient oxygen, depletion of glycogen and other nutrients, buildup of lactic acid and ADP, and failure of action potentials in the motor neuron to release enough acetylcholine.
Describe the factors that lead to muscle fatigue.
muscle fiber elongated shape
Each of our skeletal muscles is a separate organ composed of hundreds to thousands of cells, which are called _____________ because of their ________.
If the sarcomere is too stretched the myosin and actin fibers do not overlap enough to contract If the sarcomere is too contracted the myosin threads are compressed against the z discs and they cannot contract there is an optimal length of overlap that allows the best contraction, which is the usual condition of most sarcomeres. This is about 2.2 micrometers
Explain the length-tension relationship
perimysium
F
holding a book in your outstretched
Give an example of a muscle that is producing tension but not shortening.
skeletal muscle fiber - limited via satellite cells cardiac muscle fiber - limited and only under certain conditions smooth muscle fiber - considerable via pericytes
Give the capacity for generation and cells involved in muscle cell regeneration for skeletal muscle fiber, cardiac muscle fiber, and smooth muscle fiber.
muscle fiber (cell)
H
A nerve impulse reaches the synaptic end bulb and causes the release of acetylcholine, which diffuses across the synaptic cleft and binds to and activates acetylcholine receptors on the motor end plate. Binding of acetylcholine opens an ion channel in the acetylcholine receptors allowing Na+ to flow into the cell, which generates an action potential in the muscle cell.
How does a nerve impulse elicit a muscle action potential?
2 ATP from glycolysis 36 ATP from aerobic cellular respiration
How many ATP are produced by glycolysis? How many ATP are produced by aerobic cellular respiration?
rapid destruction of ACh in the synaptic cleft by acetylcholinesterase.
In a neuromuscular junction, the effect of acetylcholine (ACh) binding to receptors on the motor end plate lasts only briefly due to _____________.
myosin head
In a sarcomere, which structure contains motor proteins that convert the energy in ATP into mechanical movements?
lengthen
In an isometric contraction the muscle develops tension but does not ____________.
e. a brief delay that occurs between application of a stimulus and the beginning of contraction
In muscle physiology, the latent period refers to a. the period of lost excitability that occurs when two stimuli are applied immediately one after the other b. the brief contraction of a motor unit c. the period of elevated oxygen use after exercise d. an inability of a muscle to contract forcefully after prolonged activity e. a brief delay that occurs between application of a stimulus and the beginning of contraction
15 seconds
In skeletal muscles, the combined amounts of creatine phosphate and ATP provide enough energy for the muscle to contract maximally for approximately how long?
5
In the diagram, where would you find stored Ca2+?
Titan
In the diagram, which structure helps return a stretched sarcomere to its resting length?
8 actin
In the diagram, which structure(s) moves towards the center of the sarcomere (closer together) when the fiber contracts?
motor unit recruitment
Increasing the number of active motor units within a skeletal muscle is called
myofibril (a stack of sarcomere)
K
endomysium
L
1. ATP hydrolysis 2. Attachment of myosin to actin forming cross bridges 3. The power stroke, then detachment of myosin from actin 4. The cycle will continue as long as ATP and calcium ions are available.
List the four steps of the contraction cycle in order of occurrence. What is needed for these steps to continuously repeat?
skeletal is voluntary and controlled by the brain smooth is involuntary and controlled by the brain cardiac is involuntary and controlled by a pacemaker inside the heart itself
List the three types of muscles and indicate whether they are voluntary or involuntary and what is the major locus of control.
motor neuron
M
d. all of these answers are correct
Myofibrils contain a) contractile proteins. b) regulatory proteins. c) structural proteins. d) all of these answers are correct. e) none of these answers are correct.
c
During muscle contraction all of the following occur except a. cross-bridges are formed when the energized myosin head attaches to actin's myosin-binding site b. ATP undergoes hydrolysis c. the thick filaments slide inward toward the M line d. calcium concentration in the cytosol increases e. the Z discs are drawn toward each other
M line
During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the __________.
latent period
During which period of a twitch contraction does the muscle action potential move along the sarcolemma of the muscle cell and trigger calcium release into the sarcoplasm?
myofibril organelle
E
nucleus
P
