muscles and muscle tissue LECTURE Flashcards
______ muscle is
- not striated
- found in the intestine, respiratory, blood vessels
- involuntary, autonomic nervous system, hormones
Smooth
____ muscle is
- striated
- found in heart
- involuntary, autonomic nervous, hormones
Cardiac
____ muscle is
- striated
- voluntary, learned patterns of movement
Skeletal
Which muscle is attached to skin and bones?
Skeletal
Is cardiac muscle only found in the heart?
Yeah, duh
Is cardiac muscle striated?
Yes
Is cardiac muscle involuntary?
Yes
Is smooth muscle striated?
NO
Is smooth muscle voluntary?
No
Is smooth muscle tissue found in the walls of hollow organs?
Yes
Excitability is the ability to ____ and ____ to stimuli
receive and respond
Contractility is the ability to ____ when stimulated
shorten
Extensibility is the ability to be ______
Stretched
Elasticity is the ability to ____ to resting length
Recoil
In skeletal muscle structures, ______ is dense irregular connective tissue surrounding the entire skeletal muscle
Epimysium
In skeletal muscle structures, ______ is dense irregular connective tissue surrounding muscle fasciculi
Perimysium
In skeletal muscle structures, ______ is loose areolar connective tissue surrounding muscle fibers
Endomysium
Which skeletal muscle structure surrounds the entire skeletal muscle?
Epimysium
Which skeletal structure surrounds the muscle fasciculi?
Perimysium
which skeletal structure surrounds the muscle fibers?
Endomysium
Muscles attach directly and ______
indirectly
Muscles attach directly, ______ of muscle is fused to the Periosteum of bone
Epimysium
Muscles attach indirectly, connective tissue wrappings extend beyond the muscle as rope like _____
tendon
Which is more common, muscles that attach directly or indirectly?
Indirectly
Directly or indirectly? “epimysium of muscle is fused to the periosteum of bone”
Directly
Dir or indirectly? “connective tissue wrappings extend beyond the muscle as a roselike tendon”
Indirectly
In direct muscle attachment, the epimysium of the muscle is fused to which part of the bone?
The periosteum of the bone
In indirect attachment of muscles, connective tissue wrappings extend beyond the muscle as rope like ______.
Tendon
Does skeletal muscle have multiple nuclei?
Yes
Does skeletal muscle have many mitochondria?
Yes
_______ muscle contains myofibrils, sarcoplasmic reticulum, and T-tubules.
Skeletal
Does skeletal muscle contain glycosomes?
Yes
In skeletal muscle, glycosomes is used to store glycogen. True or false?
True
What are densely packed, rodlike elements? Myofibrils or t-tubules?
Myofibrils
Do myofibrils exhibit striations?
Yes
______ have perfectly aligned repeating series of dark _ bands and light _ bands
Myofibrils have perfectly aligned repeating series of dark A bands and light I bands
_____ : A protein fiber network which forms attachment sites for actin myofilamints
Z-disk
____: Consists of actin (thin filaments) which spans each z disk and ends at the myosin myofilaments
I band (light)
____: extends the length of the myosin myofilaments (thick filaments)
A band (dark)
____: Filaments do not overlap
H zone
____: consists of protein myomesin which holds the thick filaments together
M line
What is the smallest contractile unit of a muscle fiber?
Sarcomere
_____ is the region of a myofibril between two successful z discs
Sarcomere
_____ are composed of thick and thin myofilaments made of contractile proteins
Sarcomere
In a sarcomere, is myosin a thick or thin filament?
Thick
In a sarcomere, is actin a thick or thin filament?
Thin
In a sarcomere, is troponin a thick or thin filament?
thin
In a sarcomere, is tropomyosin a thick or thin filament?
thin
In a sarcomere, is Titin a structural protein?
Yes
In a sarcomere, is M-line a structural protein?
Yes
In a sarcomere, is a z-disk a structural protein?
Yes
_____, ______, and _____ are structural proteins of a sarcomere
Titan, M-line, and z-disk
______ is a contractile protein in thick filament
Myosin
______ is a contractile protein in thin filament
Actin
______ is a regulatory protein in thin filament (binds calcium)
Troponin
______ is a regulatory protein in thin filament
Tropomyosin
______ is a structural protein; stretching (springs)
Titin
______ is a structural protein (M-LINE) anchors myosin
Myomesin
Which muscle protein anchors myosin?
Myomesin
______ is a structural protein that anchors actin
Z-disk
Which muscle protein anchors actin?
Z-disks
Which muscle protein binds calcium?
Troponin
Which muscle protein is found in thick filament, myosin or actin?
Myosin
Which muscle protein is found in thin filament, Myosin or actin?
Actin
Does tropomyosin bind calcium?
No, troponin does
Which muscle protein stretches?
Titin
The ultrastructure of Thick Filament is composed of Myosin ______ and ______
heads and tails
In the ultrastructure of thick filament, the myosin tails contain two interwoven, heavy ______ chains
Polypeptide
Do myosin tails contain interwoven polypeptide tails?
Yes
in the ultrastructure of thick filament, myosin heads contain 2 smaller, light ______ chains that act as cross bridges during ________
Polypeptide, during contraction.
What is the binding sites for actin of thin filaments, the myosin heads or tails?
Heads
What is the binding site for ATP, myosin tails or heads?
heads
ATPase enzymes occur at myosin _____
heads
Thick filament is composed of the protein _______
Myosin
What are myosin tails composed of in the thick filament?
2 interwoven, heavy polypeptide chains
______:
-act as cross bridges during contraction
binding sites for ATP
ATPase enzymes
Myosin heads
In the ultrastructure of thin filament, twisted double strands of fibrous protein are called ____
F actin (fibrous actin)
In the ultrastructure of thin filament, F actin consists of ______ subunits
G actin (globular)
In the ultrastructure of thin filament, G actin bears active sites for ____ ____ attachment during contraction
myosin head
In the ultrastructure of thin filament ______ and _____ are regulatory proteins bound to actin
Tropomyosin and troponin
“Twisted double strand of fibrous protein: F actin” Thick or thin filament?
Thin
“f actin consists of g actin subunits” Thick or thin?
thin
During contraction, which actin bears active sites for myosin head attachment?
G-Actin
Which two regulatory proteins bind to actin?
Tropomyosin and troponin
_____: the generation of force
Contraction
______ does not necessarily cause shortening of the fiber
Contraction
In a contraction, shortening occurs when tension generated by ____ ____ on the _____(thick or thin?) filaments exceeds forces opposing shortening
cross bridges; thin
Do contractions always cause shortening of the fiber?
No
during contraction, myosin _____ bind to actin, detach, and bind again, to propel _____ filaments towards the ___line.
heads; thin; M
During contractions, do myosin heads propel towards the M line after binding to actin, detaching, and then binding again?
yes
Tropomyosin blocks the active sites on actin when….
you have low intracellular Ca2+
Myosin heads cannot attach to actin when…..
you have low intracellular Ca2+
Muscle fiber relaxes when….
you have low intracellular Ca2+
Ca2+ binds to troponin when you have…..
high intracellular Ca2+ concentrations
Troponin changes shape and moves tropomyosin away from active sites when you have…
high intracellular Ca2+ concentrations
At high intracellular Ca2+ concentrations, events of the ___ ____ ___ occur
Cross bridge cycle
When nervous stimulation ceases, ______ is pumped back into the SR and contraction ends
Ca+2
Ca2+ is pumped back into the SR and contraction ends when….
nervous stimulation ceases
Ca2+ is pumped back into the SR and contraction ends at high concentrations of
Ca+2
For the cross bridge cycle to continue, a Ca2+ ____ and adequate _____ must be present
signal; ATP
In cross bridge formation, high energy myosin ____ attaches to _____ filament
Heads attach to thin filament
Working (power) stroke in the cross bridge cycle occurs when the myosin _____ pivots and pulls thin filament toward the ____ line
Myosin head pivots and pulls thin filament toward the M Line
In the cross bridge cycle, ATP attaches to myosin heads and the cross bridge detaches. This is called _____ ____ ___
Cross Bridge detachment
In the cross bridge cycle, energy from hydrolysis of ATP cocks the myosin head into the high-energy state. This is called _____ of the ____ ____
Cocking of the myosin head
The _____ ____ is a network of smooth endoplasmic reticulum surrounding each myofibril
Sarcoplasmic Reticulum (SR)
The _____ _____ has pairs of terminal cisternae that form perpendicular cross channels
Sarcoplasmic Reticulum
The _____ _____ functions in the regulation of intracellular Ca2+ levels
Sarcoplasmic reticulum
What is the function of the SR?
Regulation of intracellular ca2+ levels
The SR is a network of smooth endoplasmic reticulum surrounding each _______
Myofibril
The SR has pairs of terminal ______ that form perpendicular ____ ____
cisternae; cross channels
_ _______ are continuous with the sarcolemma
T Tubules
_ ________ associate with the paired terminal cisternae of sarcoplasmic reticulum to form triads that encircle each sarocmere
T Tubules
T tubules associate with the paired _____ _____ of the ______ _____
terminal cisternae; sarcoplasmic reticulum
What associates with the paired terminal cisternae?
T Tubules
__ _____ conduct impulses deep into muscle fiber
T Tubules
____ _____ protrude into the inter membrane space from T tubule and SR cisternae membranes
Integral proteins
__ ____ ____ are gated channels that regulate Ca2+ release from the SR cisternae
SR foot proteins
What conducts impulses deep into muscle fiber?
T tubules
What protrudes into the inter membrane space from T tubule and SR cisternae membranes?
Integral Proteins
SR foot proteins are gated channels that regulate ____ release from the SR _______
Ca2+; Cisternae
Integral proteins protrude into the inter membrane space from ______ and ___ _____ membranes
T tubules and SR cisternae
What are the two requirements for skeletal muscle contraction?
Activation and excitation-contraction coupling
_____ is neural stimulation at a neuromuscular junction
Activation
______-_______ _____ is a generation and propagation of an action potential along the sarcolemma
Excitation-contraction coupling
____-____ ____ has a final trigger, which is a brief rise in intracellular ca2+ levels
Excitation contraction coupling
What is the final trigger in the excitation-contraction coupling?
A brief rise in intracellular ca2+ levels
A requirement for skeletal muscle contraction is activation, which is a ____ _____ at a neuromuscular junction
neural stimulation
Skeletal muscles are stimulated by somatic ____ _____
motor neurons
Axons of motor neurons travel from the ____ ____ _____ via nerves to _____ _____
central nervous system; skeletal muscles
Each ____ ending forms a ____ _____ with a single muscle fiber
Each axon ending forms a neuromuscular junction with a single muscle fiber
What are skeletal muscles stimulated by?
Somatic motor neurons
A neuromuscular junction is situated midway along the length of a ____ ____
muscle fiber
Axon terminal and muscle fiber are separated by a gel-filled space called the _____ _____
synaptic cleft
Synaptic vesicles of axon terminals containing the neurotransmitter ______ (ACh)
Acetylcholine
Junctional folds of the sarcolemma contain _____ receptors
ACh
What is the synaptic cleft?
Gel-filled space
Which enzyme quickly terminates ACh?
Acetylcholinesterase
The destruction of ACh prevents continued ____ ____ ___ in the absence of additional stimulation
muscle fiber contraction
Resting cell membrane potential is also called _______
Polarization
- Concentration of K+ inside the cell is greater than the outside of the cell
- Na+ outside the cell is greater than inside the cell.
This means the cell is ________
Polarized
To depolarize a cell, there must be simultaneous diffusion of _____ inward and _____ outward
Na+ and K+
The interior of the sarcolemma becomes less negative the more _____ diffuses
Na+
End plate potential is when ____ _____ occurs
local depolarization
One event in the generation of an action potential, end plate potential spreads to ____ ____ areas
adjacent membrane
Do voltage-gates Na+ channels need to open to generate action potential?
Yes
Does the Na+ influx decrease the membrane voltage toward a critical threshold?
Yes
When can action potential finally be reached?
When the threshold is reached
Local ______ waves continue to spread, changing the permeability of the sarcolemma.
depolarization
Voltage-regulated Na+ channels open in the ____ ____, causing it to depolarize to threshold
Adjacent patch
To repolarize, ____ channels close and voltage-gated _____ channels open
Na+ ; K+
_____ efflux rapidly restores the resting polarity
K+
Fiber cannot be stimulated and is in a _____ period until repolarization is complete
refractory
ionic conditions of the resting state are restored by the _______ pump
Na+-K+ pump
Signal to the muscle cell:
- _____ ____ travels down the cell
- Moves into the cell through the _ ______
- Triggers release of _____ from _____ ______
- _____ binds with troponin, releasing the ____ ____ ___
- muscle contraction
- action potential
- T Tubules
- Ca++ from sarcoplasmic reticulum
- Ca++ binds with troponin releasing the myosin binding sites
AP id propagated along the _____ to the T-tubules
Sarcomere
What is necessary for contraction, CA2+ or vitamin D?
Ca2+
- Tropomyosin blocks the active sites on the actin
- myosin heads cannot attach to actin
- Muscle fibers relax. This describes which kind of Ca2+ concentration?
Low levels
At higher intracellular levels of Ca2+, calcium binds to _____
Troponin
After ca2+ binds to troponin, it changes shape and moves the ____ away from the active sites
Tropomyosin
When the tropomyosin has been moved away from the active sites, the ____ ____ cycle occurs
Cross bridge
When the stimulation ceases, Ca2+ is pumped back into the _____ _____ and contraction ends
Sarcoplasmic reticulum
In an _____ ______, no shortening; muscle tension increases but does not exceed the load
Isometric contraction
In an ______ _____, muscle shortens because muscle tension exceeds the load
Isotonic contraction
In an isometric contraction there is no ______, the muscle tension increases but ___ ___ exceed the load
shortening; does not
In an isotonic contraction, the muscle shortens because….?
because the muscle tension exceeds the load
A ____ ____ is a motor neuron and all muscle fibers it supplies
Motor unit
A motor unit is a motor neuron and all ___ ____ it supplies
muscle fibers
_____ motor units are in muscles that control fine movements (fingers, eyes)
Small
_____ motor units in large weight-bearing muscles
Large
Are muscle fibers in a motor unit spread throughout the muscle?
Yes
Why are muscle fibers within a motor unit spread throughout the muscle?
SO that a single motor unit causes weak contraction of an entire muscle
Motor units in a muscle contract _______, which helps prevent fatigue
asynchronously
What do motor units do to prevent fatigue?
They contract asynchronously
Three phases of a twitch
- _____ ____: events of excitation-contraction coupling
- ___of____: cross bridge formation; tension increases
- ____of_____: Ca2+ reentry into the SR; tension declines to zero
- Latent Period
- period of contraction
- Period of relaxation
The three phases of a twitch include the latent period, which are the vents of ____ -_____ coupling
Excitation-contraction
The three phases of contraction includes the period of contraction. This period is the ___ ____ formation, and tension increases
Cross bridge
The period of relaxation, one of the three twitch phases, is when ____ reenters the SR and tension declines to 0
Ca2+
Graded muscle responses are graded by
1. Changing the ______ of the ______
frequency of stimulation
Graded muscle responses are graded by
2. Changing the _____ of the ______
strength of the stimulus
Further increase in stimulus frequency results in ____ tetanus
unfused
During a change in stimulus frequency, a Ca2+ release stimulates further contraction, and is called _____ _____
temporal summation
___ _____ : stimulus strength at which the first observable muscle contraction occurs
Threshold stimulus
Isotonic contractions are either _____ or _____
Concentric or eccentric
_____ contractions: the muscle shortens and does work
concentric
____ contractions: The muscle contracts as it lengthens
Eccentric
___ Is the only source used directly for contractile activities
ATP
Available stores of ATP are depleted in ___ to ___ seconds
4 to 6
ATP is regenerated by direct _____ of ADP by _____ phosphate
phosphorylation of ADP by creatine phosphate
ATP is regenerated by _____ which is an ______ pathway
Glycolysis; anaerobic
ATP is regenerated by ______ respiration
aerobic
Creatine phosphate stores ____ seconds of ATP
15
Anaerobic respiration is also called:
II A
Creatine phosphate is also called:
II B
Aerobic respiration is also called
I
Anaerobic respiration requires Glucose -> _ lactic acid and _ ATP
2 and 2
aerobic respiration is limited by?
Gas exchange
Aerobic respiration: myoglobin stores ____
oxygen
Anaerobic respiration has ___ to ___ seconds of activity
30 to 40
___ ___ buildup occurs during anaerobic respiration
Lactic acid
Oxygen delivery is impaired with the _____ pathway
Anaerobic
____ acid is converted into ____ acid in the anaerobic pathway
Pyruvic; lactic
___ ___ diffuses into the blood stream
Lactic acid
___ ___ is used as fuel by the liver, kidneys, and heart
Lactic Acid
___ ___ is converted back into pyruvic acid by the _____
lactic acid; liver
____ pathway produces 95% of ____ during rest and light to moderate exercise
aerobic pathway; ATP
The ____ pathway stores _____, then bloodborne glucose, ____ acid from glycolysis, and free fatty acids
Aerobic; glycogen; pyruvic acid.
Which pathway stored free fatty acids?
Aerobic
Force of contraction is affected by: _____ and the relative size of _____
Recruitment; size of fibers
Hypertrophy of cells increases _____
strength
THe number of muscle fibers stimulated is also known as _____
recruitment
Speed of contraction is controlled by the speed at which _____ ATPases split ____
myosin; ATP
Speed of contractions is controlled by the pattern of electrical activity of the ____ ____
motor neurons
Oxidative fibers use ____ pathways
aerobic
Glycolytic fibers use ____ glycolysis
anaerobic
Slow oxydative fibers are also called:
Type I
Fast oxydative fibers are called
Type II A
Fast glycolytic fibers are called
Type II B
“Thin, aerobic, slow twitch, many capillaries, myoglobin Resistant to fatigue” This is? (type I)
Slow oxydative fibers
“Medium thickness, aerobic, fast twitch,
many capillaries, myoglobin, high glycogen
Moderate resistant to fatigue
“This is? (Type IIA)
Fast oxydative fibers
“Very thick, anaerobic, fast, powerful twitch,
high glycogen, few capillaries and myoglobin
Fatigues easily
“ This is? (Type II B)
Fast glycolytic fibers
Are slow, oxydative fibers thick?
No, they are thin and aerobic.
Are slow oxydative fibers resistant to fatigue?
Yes
Are slow oxydative fibers also named Type II B?
No, they are type I
Fast oxydative fibers have medium thickness, aerobic, and result in fast twitches. true or false?
True
Do fast oxydative fibers have a moderate resistance to fatigue?
Yes
Do fast oxidate fibers lack capillaries?
No, they have many
Do all three types of muscle fibers have myoglobin?
Yes
Do fast glycolytic fibers fatigue easily?
Yes
Which muscle fiber fatigues easily? Which one is very resistant to fatigue?
Type II B(fast glycol) and Slow oxydative (type I)
Name the muscle fibers from thickest to thinnest.
Fast glycolytic
fast oxy
slow oxy
Name the two layers of smooth muscle
Longitudinal and circular
Where is smooth muscle found?
Walls of most hollow organs
______ is the alternating contractions and relaxations of smooth muscle layers
Peristalsis
When _____ layer of smooth muscle contracts, the organ dilates and shortens
Longitudinal
when ______ layer of smooth muscle contracts, the organ constricts and elongates
Circular
This describes which microscopic structure of smooth muscle? “thin and short compared with skeletal muscle fibers
“
Spindle-shaped fibers
In smooth muscle, ____ ____ is only found in the endomysium
Connective tissue
In smooth muscle, the _____ _____ is less developed than in skeletal muscle
Sarcoplasmic reticulum
Pouch like inholdings (caveolae) of the sarcolemma sequester Ca2+. This describes which microscopic type of muscle?
Smooth
Does smooth muscle contain sarcomeres, myofibrils or T tubules?
No
_____ _____ ___ innervate smooth muscle at diffuse junctions
Autonomic nerve fibers
_______ of nerve fibers store and release neurotransmitters
Varicosities
In skeletal muscle, the ratio of thick to thin filaments is 1:2. In smooth muscles, it is what?
1:13
Thick filaments have heads along their entire length in which type of muscle?
Smooth
Troponin in skeletal muscle binds to calcium. However, in smooth muscle, the protein _____ binds calcium
Calmodulin
How are myofilaments in smooth muscle arranges?
Spirally
Because myofilaments in smooth muscle are spirally arranged, this causes smooth muscle to contract in what type of manner?
A corkscrew manner
Smooth muscle has ____ bodies
Dense
Smooth muscle has dense bodies: proteins that anchor non contractile intermediate filaments to _____ at regular intervals
Sarcolemma
Smooth muscle has slow, _______ contractions
Synchronized
Some smooth muscle cells are self_______
excitatory
Some smooth muscle cells are self-excitatory, which means they ______ without external stimuli
depolarize
______ and _____ stimuli may modify the rate and intensity of a smooth muscle contraction
Neural and chemical
In smooth muscle, Ca2+ binds to and activates _______
Calmodulin
In smooth muscle, activates calmodulin activates _____ kinase
myosin
In smooth muscle, activated kinase _______ and activates myosin
phosphorylates
After the activates kinase phosphorylates and activates myosin, the ____ ____ interact with actin
Cross bridges
Are the contractions of smooth muscle energy efficient?
Yes
in smooth muscle, Myofilaments may maintain a latch state for prolonged ______
contractions
Relaxation of smooth muscle requires that ____ detaches from the calmodulin
Ca2+
Relaxation of smooth muscle contractions requires active transport of Ca2+ into the _____ _____
sarcoplasmic reticulum
Relaxation of smooth muscle contractions requires the dephosphorylation of _____ to reduce ATPase activity
myosin
Multiunit smooth muscle is located in large airways. True or false?
True
which type of smooth muscle is found in arrector pili muscles?
Multiunit
Are gap junctions rare in multiunit smooth muscle?
Yes
How is multiunit smooth muscle arranged?
In motor units
Do large arteries contain multiunit skeletal muscle?
No, they contain multiunit smooth muscle
____ _____ occur in response to neural stimuli (smooth multiunit muscle)
Graded contractions
