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264 Cards in this Set

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Are muscle tissues highly cellular or cellular?
highly cellular
slide 2
Are muscle tissues poorly vascularized or well vascularized?
well vascularized
slide 2
What do muscle tissues transform?
chemical energy (ATP) into directed mechanical energy
slide 2
What are three prefixes referring to muscle?
myo, mys, sarco
slide 2
What are the principal functions of muscle tissue?
- producing movement

- maintaining posture and body position

- stabilizing joints

- generating heat
slide 3
What is excitability?
the ability to receive and respond to stimuli
slide 4
What is contractility?
the ability to shorten when stimulated
slide 4
What is extensibility?
the ability to be stretched
slide 4
What is elasticity?
the ability to recoil to resting length
slide 4
What are the three types of muscle tissue?
- skeletal muscle

- cardiac muscle

- smooth muscle
slide 5
What specific tissue type is best described :

" cells are long and cylindrical "
skeletal muscle tissue
What specific tissue type is best described:

" cells are multinucleate "
skeletal muscle tissue
Do skeletal muscle cells have striations?
yes
_______ and ________ muscle cells have striations.
skeletal ; cardiac
What specific tissue type is best described:

" attached to bones and skin "
skeletal muscle tissue
What specific tissue type is best described:

" involved in voluntary movement/conscious control "
skeletal muscle tissue
Skeletal muscle cells are also called _______.
fibers
Skeletal muscle tissue cells are ____nucleate.
multinucleate
______ muscle tissue cells are located only in the heart.
cardiac
Cardiac muscle tissue cells are involved in ____________ movement.
involuntary
Cardiac muscle tissue cells are _____nucleate.
uninucleate
What specific tissue type is described:

" cells are branched "
cardiac muscle tissue
What specific tissue type is described:

" not striated "
smooth muscle tissue
What specific tissue type is described:

" cells are spindle-shaped "
smooth muscle tissue
What specific tissue type is described:

" in the walls of hollow organs, like the stomach, urinary ladder, and respiratory passages "
smooth muscle tissue
Smooth muscle tissue is involved in _________ movement.
involuntary
Skeletal muscle is characterized as an _______.
organ
Why is skeletal muscle characterized as an organ?
It is made up of several kinds of tissues, like:

- nerve and blood supply

- connective tissue

- attachments

- skeletal muscle fibers
Why are skeletal muscle cells associated with connective tissue?
Since contracting muscle fibers are not as effective if they work in isolation
Explain how a contracting unit is formed.
Each fiber is bound to adjacent fibers to form bundles, and bundles are bound to adjacent bundles to form a contracting unit.
Skeletal muscles have sheaths of connective tissue. What are the sheaths of connective issue called?
- endomysium

- perimysium

- epimysium
Skeletal muscles have sheaths of _________.
connective tissue
What term is described:

" the most internal connective sheath of skeletal muscle "
endomysium
What sheath of connective tissue is described:

" surrounds individual fibers "
endomysium
What sheath of connective tissue is best described:

" consists of fine areolar connective tissue "
endomysium
What sheath of connective tissue is best described:

" binds fibers into fascicles "
perimysium
What are fascicles?
groups of fibers
What sheath of connective tissue is best described:

" consists of fibrous connective tissue "
perimysium
What connective tissue sheath is best described:

" surrounds the entire muscle "
epimysium
What connective tissue sheath is best described:

" consists of dense irregular connective tissue "
epimysium
What connective tissue sheath is best described:

" the most external sheath "
epimysium
What term is described:

" fibrous connective tissue that covers muscles and attaches to skin "
fascia
What is fascia?
fibrous connective tissue that covers muscles and attaches to skin
What does superficial fascia do?
secures skin to underlying structures
_____ fascia is described:

" secures skin to underlying structures "
superficial fascia
_____ fascia is described:

" blends with epimysium "
deep fascia
Deep fascia blends with _______.
epimysium
_____ fascia is described:

" surrounds adjacent muscles "
deep fascia
____ fascia binds adjacent muscles in functional groups.
deep fascia
Deep fascia binds adjacent muscles in _________.
functional groups
What are the two types of fascia?
superficial and deep
Skeletal muscle has a _______ rate of metabolic activity.
high
Since skeletal muscle has a high rate of metabolic activity, it requires what to receive oxygen and nutrients, and to eliminate waste products.
blood vessels
What is the function of the blood vessels of skeletal muscle?
to give oxygen and nutrients to skeletal muscle and to eliminate waste products
Each muscle is served by one or more what?
arteries, veins, and blood vessels
Capillaries of skeletal muscle are located in __________.
endomysium
What connective tissue sheath is described:

" contains capillaries of skeletal muscle "
endomysium
Muscles attach to a bone on each end via _________.
tendons
Tendons are made up of what type of tissue?
dense regular connective tissue
Muscle attachments may be either _______ or _________.
direct ; indirect
The following statement describes __________ muscle attachments:

" epimysium of muscle is fused to the periosteum of bone or perichondrium of cartilage "
direct
In direct attachments, the ______ of muscle is fused to the periosteum of bone or perichondrium of cartilage.
epimysium
In direct attachments, the epimysium of muscle is fused to what?
periosteum of bone or perichondrium of cartilage
The following statement describes ________ attachment:

" connective tissue wrappings extend beyond the muscle as a ropelike tendon or sheetlike aponeurosis "
indirect
_______ attachment makes use of a tendon.
indirect
______ attachment makes use of sheetlike aponeurosis.
indirect
What is retinaculum?
a group of tendons bound by connective tissue
Muscle is covered externally by __________.
epimysium
What term is described by the following statement:

" consists of hundreds to thousands of muscle cells, plus connective tissue wrappings, blood vessels, and nerve fibers "
muscle (organ)
What term is described by the following:

" a discrete bundle of muscle cells, segregated from the rest of the muscle by a connective tissue sheath "
fascicle
Fascicle is surrounded by __________.
perimysium
What term is best described by the following:

" an elongated multinucleate cell; it has a banded(striated) appearance "
a muscle fiber (cell)
A muscle fiber is surrounded by __________.
endomysium
What term is best described by the following statement:

" plasma membrane of muscle cell "
sarcolemma
What term is best described by the following statement:

" cytoplasm of muscle cell "
sarcoplasm
What term is best described by the following statement:

" granules of stored glycogen "
glycosomes
What term is best described by the following statement:

" red pigment that stores oxygen "
myoglobin
What term is best described by the following statement:

" ER network of muscle cell "
sarcoplasmic reticulum
What do transverse (T) tubules do?
conduct nerve impulses
What are transverse (T) tubules?
sarcolemma extending into the cell
Explain the relationship between myofibrils and myofilaments.
Myfilaments make up myofibrils
What term is best described by the following statement:

" densely packed, rodlike bundles of filaments "
myofibrils
There are two types of myofilaments. What are they?
thick and thin
thick myofilaments contain _______.
myosin
thin myofilaments contain ________.
actin
Myofibrils and myofilaments run _______ to cell's length.
parallel
80% of muscle fiber cell volume is made up of what?
myofibrils and myofilaments
Describe the myofilament arrangement in a muscle fiber cell.
perfectly aligned repeating series of dark and light bands along the myofibril's length.
Dark ______ bands
A
Light ______ bands
I
Due to the myofilament arrangement, muscle cells exhibit what?
striations
The arrangement of thick and thin myofilaments between a pair of Z lines forms a repeating pattern that serves as the ____________.
sarcomere
What is the sarcomere?
the basic unit of skeletal muscle contraction
The arrangement of thick and thin myofilaments between a pair of ___________ forms a repeating pattern that serves as the sarcomere (basic unit of skeletal muscle contraction).
Z lines
The smallest contractile element of a skeletal muscle fiber is a ___________.
sarcomere
The region of myofibril between two successive Z discs is ___________.
a sarcomere
A sarcomere is a region of myofibril between two what?
successive Z discs?
The sarcomere is composed of what?
thick and thin myofilaments, made of contractile proteins
______ filaments run the entire length of an A band
thick
_______ filaments run the entire length of an I band and part way into the A band.
thin
thin filaments run the entire length of an _____ band and part way into the _____ band.
I ; A
The A band has an ____ zone.
H zone
The A band has an H zone that is what?
a lighter region in midsection where filaments do not overlap
What part of a sarcomere is described:

" a lighter region in midsection where filaments do not overlap "
H zone of the A band
The A band has an M line that is what?
a dark band that vertically bisects the H zone; holds adjacent thick filaments together
The H zone and M line are part of the what?
A band
The Z disc is part of the what?
I band
What term is best described:

" holds adjacent thick filaments together "
M line
What term is best described:

" dark band that vertically bisects the H zone"
M line
What term is best described:

" darker midline that anchors thin filaments "
Z disc
What term is best described:

" connects myofibrils to one another "
Z disc
Thick filaments run where?
the entire length of an A band
Thin filaments run where?
the entire length of an I band and pat way into an A band
What is sarcoplasmic reticulum (SR)?
specialized ER of muscle cells
What term is best described:

" interconnecting network of smooth ER tubules surrounding each myofibril "
Sarcoplasmic reticulum
Sarcoplasmic reticulum is an interconnecting network of _________ surrounding each myofibril.
smooth ER tubules
Sarcoplasmic reticulum is an interconnecting network of smooth ER tubules surrounding what?
each myofibril
Another term for terminal cisternae is what?
sarcoplasmic reticulum tubules (SR tubules)
What do terminal cisternae (SR tubules) form?
perpendicular cross channels at the A band-I band junctions
What forms perpendicular cross channels at the A band-I band junctions?
terminal cisternae (SR tubules)
What term is best described:

" functions in the regulation of intracellular calcium levels "
Sarcoplasmic reticulum
Sarcoplasmic reticulum functions in the regulation of what?
intracellular calcium levels
What term is best described:

" elongated tubules of sarcolemma protruding into cell interior at A band- I band junctions "
T tubules
What do T tubules do?
conduct nerve impulses from sarcolemma to every sarcomere
What term is best described by the following:

" conduct nerve impulses from sarcolemma to every sarcomere "
T tubules
T tubules conduct nerve impulses from sarcolemma to every sarcomere. This ensures what?
that every myofibril in a muscle fiber contracts at the same time
Every myofibril in a muscle fiber contracts at the same time because ....
T tubules conduct nerve impulses from sarcolemma to every sarcomere
What are triads?
successive groupings of T tubles flanked by paired terminal cisternae
_________ conduct impulses deep into the muscle fiber.
T tubules
What term is best described :

" integral proteins protrude into the intermembrane space from T tubule and SR cisternae membranes "
triad
Integral proteins protrude into the intermembrane space from ________ and _________.
T tubules ; SR cisternae membranes
_________ proteins act as voltage sensors.
T tubule
T tubule proteins act as what?
voltage sensors
What are SR foot proteins?
gated channels that regulate calcium release from the SR cisternae
What is contraction?
the generation of force
True or false: contraction always causes shortening of the fiber
false because contraction does not necessarily cause shortening of the fiber
True or false: contraction does not necessarily cause shortening of the fiber
true
When does shortening of the fiber occur?
when tension generated by cross bridges on the thin filaments exceeds forces opposing shortening
When tension generated by cross bridges on the thin filaments exceeds forces opposing shortening what happens?
shortening occurs
In the relaxed state, what happens to thin and thick filaments?
thin and thick filaments overlap only slightly
thin and thick filaments overlap only slightly in what state?
relaxed state
During contraction, what happens to thick and thin filaments?
myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments toward the M line
During contraction, ______ heads on thick filaments bind to ______ on thin filaments, propelling the thin filaments towards the M line
myosin ; actin
During contraction, myosin heads on thick filaments bind to actin on thin filaments, propelling the _______ filaments toward the M line
thin
During contraction, myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments towards what?
the M line
During _______ myosin heads on thick filaments bind to actin on thin filaments, propelling the thin filaments towards the M line
contraction
_______ fibers slide past the ______ filaments, so that actin and myosin overlap during contraction
thin ; thick
Thin fibers slide past the thick filaments, so that ______ and ______ overlap during contraction.
actin ; myosin
Describe how thin fibers slide past the thick filaments during contraction
- I band shortens

- distance between Z bands decreases

- H zone disappears

- Contiguous A bands move closer together but do not change in length
What has to happen for the muscle cells to shorten, and for the whole muscle to shorten?
H zones shorten and disappear, causing the sarcomeres to shorten
What happens to I bands during contraction?
I bands shorten
What happens to A bands during contraction?
they move closer together but do NOT change length
What happens to Z bands during contraction?
the distance between Z bands decreases
What happens to H zones during contraction?
they shorten and disappear
What is the "main step" of contraction that causes sarcomeres to shorten?
H zones shorten and disappear
What are the two requirements for skeletal muscle contraction?
1. activation

2. excitation-contraction coupling
What is activation?
neural stimulation at a neuromuscular junction
What is excitation-contraction coupling?
- generation and propagation of an action potential along the sarcolemma

- final trigger: a brief rise in intracellular calcium levels
What is the final trigger of skeletal muscle contraction?
a brief rise in intracellular calcium levels
In order for skeletal muscle to contract, an __________ must be generated and propogated along the sarcolemma.
action potential
In order for skeletal muscle to contract an action potential must be generated and propogated along the ________.
sarcolemma
In order for skeletal muscle to contract, what has to happen first?
activation = neural stimulation at a neuromuscular junction
Skeletal muscles are stimulated by what?
somatic motor neurons
Somatic motor neurons stimulate what?
skeletal muscle
Axons of motor neurons travel from ___________ via nerves to _________.
nervous system ; skeletal muscles
Axons of motor neurons travel from the central nervous system via _______ to skeletal muscles.
nerves
Each axon forms what as it enters a muscle?
several branches
________ of motor neurons travel from the central nervous system to skeletal muscles.
Axons
Motor end plates are where axons contact ________.
sarcolemma
Motor end plates are where ______ contact sarcolemma.
axons
__________ are where axons contact sarcolemma.
Motor end plates
Motor end plates form a ___________ with a single muscle fiber
neuromuscular junction
Motor end plates form a neuromuscular junction with a ____________.
single muscle fiber
__________ form a neuromuscular junction with a single muscle fiber.
Motor end plates
What term is best described by the following:

" situated midway along the length of a muscle fiber "
neuromuscular junction
A neuromuscular junction is situated where?
midway along the length of a muscle fiber
The axon terminal and muscle fiber are separated by a space called the _________.
synaptic cleft
What is the synaptic cleft?
a space that separates the axon terminal and muscle fiber.
The __________ and _________ are separated by a space called the synaptic cleft.
axon terminal ; muscle fiber
Synaptic vesicles of axon terminal contain what neurotransmitter?
acetylcholine (ACh)
________ of axon terminals contain the neurotransmitter acetylcholine (ACh)
Synaptic vesicles
Synaptic vesicles of ___________ contain the neurotransmitter acetylcholine.
axon terminals
Acetylcholine is a type of ________.
neurotransmitter
Junctional folds of the sarcolemma contain what?
acetylcholine receptors
_________ of the sarcolemma contain acetylcholine receptors.
junctional fods
Junctional folds of the _______ contain the ACh receptors.
sarcolemma
What is the sliding filament theory of contraction?
during contraction, the thin filaments slide past the thick ones so that the actin and myosin filaments overlap to a greater degree.
In a relaxed muscle fiber, what happens to the thick and thin filaments?
they overlap only at the ends of the A bands.
Thick and thin filaments overlap only at the ends of the A bands when?
when they are relaxed
Describe the events in detail that occur at the neuromuscular junction
- The nerve impulse arrives at the axon terminal
- voltage gated calcium channels allow calcium to flood in side the axon terminal
- the presence of calcium causes ACh to be released into the synaptic cleft
- ACh diffuses across the synaptic cleft and attaches to ACh receptors on the sarcolemma
- ACh binding opens ion channels that allow sodium into the muscle and potassium out of the fiber. Since more sodium diffuses in than K diffuses out, the muscle becomes slightly less negative, known as depolarization.
- Since the inside of the muscle now has less potassium, this "attracts" more potassium to diffuse back into the muscle....which is repolarization.
- ACh effects are terminated.
The very first event at the neuromuscular junction is what?
a nerve impulse (axon potential ) arrives at the axon terminal of a motor neuron
After an axon potential arrives at the axon terminal, what happens at the neuromuscular junction?
AcH is released into the synaptic cleft
After AcH is released into the synaptic cleft, what happens at the neuromuscular junction?
AcH binds to receptors on the sarcolemma
After ACh binds to receptors on the sarcolemma, what happens at the neuromuscular junction? (briefly).
Electrical events lead to the generation of muscle contraction....
After a muscle contraction has been generated, what happens at the neuromuscular junction?
ACh effects are terminated.
What process is best described by the following:

" sequence of events by which transmission of an AP along the sarcolemma leads to the sliding of myofilaments"
excitation-contraction coupling
Transmission of the action potential along the sarcolemma leads to what?
sliding of the filaments
what leads to sliding of the filaments?
transmission of the action potential along the sarcolemma
transmission of the ________ along the sarcolemma leads to sliding of the filaments
action potential
transmission of the action potential along the _________ leads to sliding of the filaments
sarcolemma
After the sliding of the filaments, the action potential goes from the sarcolemma to what?
T tubules
After the sliding of the filaments, the action potential goes from what to the T tubules?
sarcolemma
voltage sensitive proteins simulate what release from the sarcoplasmic reticulum?
calcium
_______stimulate calcium release from the sarcoplasmic reticulum
voltage sensitive proteins
voltage sensitive proteins stimulate calcium release from what?
sarcoplasmic reticulum
What ULTIMATELY causes filament sliding?
calcium release
what ULTIMATELY causes muscle contraction?
filament sliding/calcium release
What is a motor unit?
a motor neuron and the group of muscle cells it stimulates
What term describes the following:

" a motor neuron and the group of muscle cells it stimulates "
motor unit
Axons of motor neurons extend from ___________ to muscle.
spinal cord
Axons of motor neurons extend from the spinal cord to ________.
muscle
Axons of motor neurons extend from the ________ to ________.
spinal cord; muscle
The nerve-muscle functional unit is known as the what?
motor unit
Axons of ________ extend from the spinal cord to muscle.
motor neurons
_______ of motor neurons extend from the spinal cord to muscle.
Axons
In the muscle, each axon divides into a number of ___________.
axon terminals
In the muscle, each ________ divides into a number of axon terminals.
axon
In the muscle, each axon divides into a number of axon terminals that form ____________ with muscle fibers.
neuromuscular junctions.
In the muscle, each axon divides into a number of axon terminals that form neuromuscular junctions with ___________.
muscle fibers
Axon terminals form neuromuscular junctions with __________.
muscle fibers
Axon terminals form ______________ with muscle fibers.
neuromuscular junctions
________ form neuromuscular junctions with muscle fibers.
Axon terminals
When a motor neuron fires,what happens to all the muscle fibers it innervates?
contract
When do all the muscle fibers that innervate a motor neuron contract?
When a motor neuron fires/releases AP
Muscle fibers from a motor unit are spread throughout the muscle so that a single motor unit causes what?
weak contraction of entire muscle
muscle fibers from a motor unit are _________________ so that a single motor unit causes weak contraction of an entire muscle.
spread out throughout the muscle
muscle fibers from a motor unit are spread throughout the muscle so that what can cause weak contraction of an entire muscle?
a single motor unit
Motor units in a muscle usually contract asynchronously. Why?
to help prevent fatigure
Motor units in a muscle usually contract ____________ to help prevent fatigue.
asynchronously
the number of motor units activated is based on what?
the magnitude of the task; greater task = more motor units.
muscles that control fine movements have ______ motor units.
small #
muscles that control weight bearing movements have ______ motor units
large #
What's a muscle twitch?
Response of a motor unit to a single firing of its motor neuron
What term is described by the following:

"response of a motor unit to a single firing of its motor neuron "
muscle twitch
What term is best described by the following statement:

" simplest contraction observable "
muscle twitch
What term is best described by the following statement:

" graphic recording of contractile activity"
myogram
What is a myogram?
a graphic recording of contractile activity
A myogram is a graphic recording of _________ activity.
contractile
What are the three phases of a muscle twitch?
latent period, period of contraction, period of relaxation
What phase of a muscle twitch is best described by the following statement:

" first few milliseconds following stimulation "
Latent period
What phase of a muscle twitch is best described by the following statement:

" muscle tension increases but no response seen on myogram "
latent period
During the latent period of a muscle twitch, muscle tension _______ but there is no response seen on myogram.
increases
During the latent period of a muscle twitch, muscle tension increases. What is seen on a myogram?
no response seen on a myogram, despite muscle tension increase!
What phase of a muscle twitch is best described by the following statement:

" 10-100 ms "
period of contraction
What phase of a muscle twitch is described by the following:

" If tension is great enough to overcome resistance of load, the muscle shortens"
period of contraction
During the period of contraction phase of a muscle twitch, if tension is great enough to overcome resistance of the load, what happens?
muscle shortens
During the period of contraction phase of a muscle twitch, if tension is great enough to overcome __________, the muscle shortens.
resistance of the load
During the period of contraction phase of a muscle twitch, what has to happen for the muscle to shorten?
Tension must be great enough to overcome resistance of the load.
What phase of a muscle twitch is described by the following:

" Contractile force declines and muscle tension decreases to 0."
period of relaxation
During a period of relaxation of a muscle twitch, contractile force declines. What happens to muscle tension?
It decreases to zero.
During a period of relaxation of a muscle twitch, what happens to contractile force and muscle tension?
Contractile force declines and muscle tension decreases to zero.
What term is best described by the following statement:

" Constant, slightly contracted state of all muscles "
muscle tone
What is muscle tone?
Constant, slightly contracted state of all muscles
What causes muscle tone?
Due to spinal reflexes that activate groups of motor units alternately in response to input from stretch receptors in muscles
_________ is due to spinal reflexes that activate groups of motor units alternately in response to input from stretch receptors in muscles
muscle tone
Muscle tone is due to __________ that activate groups of motor units alternately in response to input from stretch receptors in muscles.
spinal reflexes
Muscle tone is due to spinal reflexes that do what ?
activate groups of motor units alternately in response to input from stretch receptors in muscles
Muscle tone is due to spinal reflexes that activate groups of motor units alternately in response to input from ____________.
stretch receptors in muscles
What does skeletal muscle tone do?
maintains posture and stabilizes joints
______ keeps muscles firm, healthy, and ready to respond.
Muscle tone
During what phase of a muscle twitch does calcium re-enter the sarcoplasmic reticulum?
period of relaxation
During the period of relaxation phase of a muscle twitch, what does calcium do?
re-enters the sarcoplasmic reticulum
During the period of relaxation phase of a muscle twitch, what re-enters the sarcoplasmic reticulum?
calcium
During the period of relaxation phase of a muscle twitch, calcium re-enters what?
the sarcoplasmic reticulum