Pre-Lab Histology and Function of Muscle Tissue
larger, thicker, glycogen, pale, washed out
Purkinje fiber cells are blanker and blanker than cardiac muscle cells abundance of blank appear blank and washed out, and typically stain blanker
myocardium, endocardium, subendocardial, endocardium, interventricular septum
Purkinje fibers are located between the blank and blank; commonly seen in the blank layer of the blank high concentration is found at the blank blank
TnT
Troponin T
red (slow, oxidative fibers (type I), intermediate (fast, oxidative-glycolytic fibers (type IIa)), white (fast, glycolytic fibers (Type IIb)
3 skeletal muscle fiber types
AV
AV node transmits electrical impulses to Purkinje fibers of the ventricles
sarcomere
EM of three skeletal muscle fibers distance between Z line to Z line is the blank
I, Z, A, H
H&E light microscopic images of skeletal muscle some striations showed at higher magnification, blank band/blank disc is lighter pink/white at higher magnification, blank band/blank zone is darker pink - in between light lines blank are large and oval and in between striated sections there are capillaries, endothelial cells, and blood vessels as well
cardiac, glycogen, mitochondria
a feature of blank muscle is the presence of blank deposits - source of energy in the form of glucose, along with high concentration of blank in this muscle
sarcomere
a structural unit of a myofibril in striated muscle, consisting of a dark band and the nearer half of each adjacent pale band
sympathetic
accelerating heartbeat impulses arrive via blank nervous system
calcium, troponin, tropomyosin, actin, myosin
actomyosin cross-bridge cycle blank ions released upon neural stimulation bind blank, changing its shape and moving blank on the blank to expose the blank-binding active sites and allowing cross-bridges to form
cadherin
blank a glycoprotein that forms the belt-like "plaque" in desmosome
myoglobin
blank a heme-containing protein that stores oxygen
norepinephrine
blank a neurotransmitter involved in arousal, as well as in learning and mood regulation
titin
blank a protein that positions the myosin filament to maintain equal spacing between actin filaments (3700 kDa) has scaffolding and elastin properties
syncytium
blank a single cell or cytoplasmic mass containing several nuclei, formed by fusion of cells or by division of nuclei
myocyte
blank a skeletal muscle fiber that is a single muscle cell
parturition
blank act of giving birth
desmosomes
blank anchoring junctions that prevent cells from being pulled apart
acetylcholinesterase
blank breaks down acetylcholine, preventing continuous stimulation and allowing the muscle to relax
fascicles
blank bundles of muscle fibers
calsequestrin
blank calcium-binding protein within the sarcoplasmic reticulum which aids in storage of intracellular Ca2+
myocardium
blank cardiac muscle
perimysium
blank connective tissue surrounding a fascicle
endomysium
blank connective tissue surrounding a muscle fiber
epimysium
blank connective tissue surrounding an entire muscle
sarcomere
blank contractile unit of a muscle fiber
sarcoplasm
blank cytoplasm of a muscle cell
dystrophin
blank cytoskeleton protein responsible for providing strength to muscle when there is mutation here, degradation of mainly skeletal muscle but also other types of muscles
Z line
blank dark thin protein band to which actin filaments are attached in a striated muscle fiber, marking the boundaries between adjacent sarcomeres
myoblast
blank embryonic cell that develops into a cell of muscle fiber
connectin
blank extends from Z disc to M line stabilizes thick filaments and has "springlike" properties (passive tension)
sympathetic
blank fight or flight
nerve, epineurium
blank formed by groups of nerve fascicles wrapped in and packed with blank
oxytocin
blank hormone released by the posterior pituitary gland that stimulates uterine contractions during childbirth and milk ejection during breastfeeding - potent stimulator
TnI
blank inhibitory subunit that binds to actin
endocardium
blank inner lining of heart
desmin
blank intermediate filament in muscle
myofilaments, myosin, actin
blank made up of thick filaments (blank) and thin filaments (blank)
cadherins
blank major link proteins in desmosomes/macula adherens
connexins
blank major link proteins in gap junctions
rhabdomyosarcoma
blank malignant skeletal muscle tumor
sarcoma
blank malignant tumor of connective tissue
rhabdomyosarcoma
blank malignant tumor of striated muscle
striated
blank marked with parallel bands; grooved
rhabdomyosarcoma
blank most common soft tissue sarcoma in children
fiber
blank muscle cell
tropomyosin
blank muscle protein that forms a complex with troponin, regulating the interaction of actin and myosin in muscular contraction
myocardium
blank muscular, middle layer of the heart
connexins, connexin, connexin 43
blank mutations in blank genes are major pathogenic factors in several diseases ex. blank blank - most abundant protein forming gap junctions in cardiac muscle - mutations in this gene have been associated with sudden infant death syndrome, which is linked to cardiac arrhythmia; and heart malformations
rhabdomyosarcoma
blank neoplasm that is composed of skeletal myoblast cells
epinephrine
blank neurotransmitter secreted by the adrenal medulla in response to stress also known as adrenaline
epicardium
blank outer layer of the heart
visceral
blank pertaining to the internal organs
sarcolemma
blank plasma membrane of a muscle cell; cell membrane + lamina
sarcolemma
blank plasma membrane of a muscle fiber
striated
blank presence of sarcomeres
tropomodulin
blank protein which binds and caps the minus end of actin, and regulates the length of actin filaments
axial
blank relating to head, neck, and trunk, the axis of the body
appendicular
blank relating to limbs and their attachments to the axis
parasympathetic
blank rest and digest
caveolae
blank shallow invaginations of smooth muscle cell sarcolemma functions to control Ca2+ release
myoblasts
blank stem cells that fused to form each muscle fiber early in development
myomesin
blank structural protein that forms M line of sarcomere
acetylcholinesterase
blank the enzyme that breaks down acetylcholine in the synaptic cleft
connexins
blank the membrane proteins present at gap junctions
peristalsis
blank the process of wave-like muscle contractions of the alimentary tract that moves food along
myosin
blank thick filament
actin
blank thin filaments
myofibril
blank tightly packed filament bundles found within skeletal muscle fibers
TnI
blank troponin subunit that regulates actin-myosin interaction
TnC
blank troponin subunit that binds Ca2+ ions
TnT
blank troponin subunit that binds to tropomyosin
dystrophin, actin
blank acts as a mechanical link between the sarcolemma and the cytoskeletal actin amino terminus binds to blank filaments in healthy cells, it protects muscle cell from damage caused by force of contraction
myomesin, C proteins
blank and blank blank proteins that, together, bind myosin and hold thick filaments in register at the M line
smooth, cardiac, centrally
blank and blank muscles have blank located nuclei in individual cells
I
blank band is actin-heavy and titin - thin filaments and connection to Z disc
A
blank band is heavier in skeletal muscle
I
blank band is lighter in skeletal muscle
A
blank band is myosin-heavy - thick filaments
macula adherens
blank blank -strong junctions which resist stretching and twisting -also called desmosome (looks like a spot-weld between cells)
AV bundle
blank blank The structure along which the AV node rapidly transmits its signal to the ventricular tissues associated with conduction system and cardiac muscle
atrioventricular bundle
blank blank a bundle of modified heart muscle that transmits the cardiac impulse from the atrioventricular node to the ventricles causing them to contract
skeletal muscle
blank blank a muscle that is attached to the bones of the skeleton and provides the force that moves the bones
atrioventricular node
blank blank a node of specialized heart muscle located in the septal wall of the right atrium
sinoatrial node
blank blank a small mass of tissue that is made up of Purkinje fibers, ganglion cells, and nerve fibers, that is embedded in the musculature of the right atrium, and that originates the impulses stimulating the heartbeat
arrector pili
blank blank a smooth muscle attached to hair follicles that causes "goose bumps" to appear on the skin when contracted
atrioventricular node
blank blank a specialized mass of conducting cells located at the atrioventricular junction in the heart
zonula adherens
blank blank adhering type junction that occurs as a sheet between EPITHELIAL cells BELT DESMOSOMES analogous to fascia adherens in cardiac muscle
M line
blank blank attachment site for thick filaments
muscularis externa
blank blank bilayer of smooth muscle which consists of a layer running circularly and another running longitudinally responsible for segmentation and peristalsis
ryanodine receptor
blank blank calcium-release channel found in the lateral sacs of the sarcoplasmic reticulum in skeletal muscle cells
anchoring junction, intermediate
blank blank cell to cell junction couples the blank filaments to the plasma membrane at regions of cell-cell adhesion
communicating junction
blank blank cell to cell junction creates a conduit between two adjacent cells for passage of small ions and informational micro-molecules
Z disc
blank blank coin-shaped sheet of proteins that anchors the thin filaments and connects myofibrils to one another
visceral pericardium
blank blank covering layer of the heart
dense bodies
blank blank cytoplasmic structure to which thin filaments of a smooth muscle fiber are anchored
A band
blank blank dark band
terminal cisternae
blank blank enlarged areas of the sarcoplasmic reticulum surrounding the transverse tubules
T tubules
blank blank finger-like invaginations of plasma membrane; extend into interior of fiber and surround or circle the myofibrils they are aligned with the A and I bands of the sarcomere
nerve fascicle, perineurium
blank blank formed by groups of nerve fibers held together with blank
nerve fiber, endoneurium
blank blank formed by the axon of a neuron and, when myelinated, by its myelin and wrapped in blank
satellite cells
blank blank function to regenerate skeletal muscle
smooth muscle
blank blank involuntary muscle found inside many internal organs of the body
cardiac muscle
blank blank involuntary muscle tissue found only in the heart
I band
blank blank light band
M line
blank blank middle of sarcomere
sinoatrial node
blank blank pacemaker of the heart
intercalated disc
blank blank part of the sarcolemma that connects cardiac tissue, and contains gap junctions and desmosomes
C protein
blank blank part of the thick filament involved in holding the tails of myosin in a correct spatial arrangement
interventricular septum
blank blank partition between the right and left ventricles
gap junctions
blank blank provide cytoplasmic channels between adjacent animal cells
H zone
blank blank region at the center of an A band of a sarcomere that is made up of myosin only - only thick filaments
Z disc
blank blank separates the sarcomeres from each other - in the I band
Purkinje fibers
blank blank specialized cardiac muscle fibers/modified cardiac muscle cells that form a network in the ventricular walls that conduct electrical impulses responsible for the contractions of the ventricles
sarcoplasmic reticulum
blank blank specialized endoplasmic reticulum of muscle cells, stores calcium ions
rigor configuration
blank blank starting position of muscle contraction cycle; myosin is bound tightly to actin, but not to ATP or ADP
satellite cell
blank blank stem cell that helps to repair muscle cells
skeletal muscle
blank blank striated and voluntary muscles
titin filament
blank blank structural protein that connects Z disc to M line of sarcomere, thereby helping to stabilize thick filament position can stretch and then spring back unharmed, and thus accounts for much of the ELASTICITY and EXTENSIBILITY of myofibrils
M line
blank blank supporting proteins that hold the thick filaments together in the H zone
H zone, shorter
blank blank the region at the center of an A band of a sarcomere that is made up of myosin only gets blank (and may disappear) during muscle contraction
arrector pili
blank blank tiny muscle fibers attached to the hair follicles that cause the hair to stand erect
T tubules
blank blank tubular infoldings of the sarcolemma which penetrate through the cell and emerge on the other side
myosin II
blank blank type of myosin that produces contraction by sliding actin filaments
myosin head
blank blank bind to specific sites on actin molecules to form cross bridges
Duchenne Muscular Dystrophy
blank blank blank a human genetic disease caused by a sex-linked recessive allele characterized by progressive weakening and a loss of muscle tissue a condition with symmetrical weakness and wasting of pelvic, shoulder, and proximal limb muscles
skeletal muscle fiber, myoblasts
blank blank blank multi-nucleated syncytium formed during development by the fusion of individual small muscle cells called blank
visceral striated muscle
blank blank blank muscle type that is restricted to the soft tissues such as the tongue, pharynx, upper part of the esophagus and lumbar portion of the diaphragm
sliding filament theory, swinging cross-bridge
blank blank blank theory that actin filaments slide toward each other during muscle contraction, while the myosin filaments are still also called blank blank-blank mechanism
sudden infant death syndrome (SIDS)
blank blank blank blank (blank) a condition that occurs when an infant stops breathing, usually during the night, and suddenly dies without an apparent cause
fascia adherens
blank blank junction the site at which thin filaments in the terminal sarcomere anchor onto the plasma membrane
Z disc/Z line
blank blank/blank blank attachment site for thin filaments
dense, alpha-actinin
blank bodies in smooth muscle contain blank-blank for thin filament attachment
titin
blank connects thick filaments to the Z disc or Z line
purkinje
blank fibers network of fibers found in the cardiac muscle that carries the electrical impulses resulting in the contraction of the ventricles
myoblasts
blank fuse to form a skeletal muscle fiber
desmosomes, fascia adherens
blank in cardiac muscle intercalated discs they bind the individual muscle cells to one another, in conjunction with the blank blank junction
gap
blank junctions in intercalated discs form dynamic intercellular ionic pores from connexins
dystrophin
blank links thin filaments to proteins of sarcolemma
cardiac
blank muscle characterized by branching striations nucleus glycogen intercalated disc
smooth
blank muscle characterized by nuclei muscle cells
skeletal
blank muscle characterized by nuclei striations muscle fiber connective tissue
cardiac, smooth
blank muscle and blank muscle contain gap junctions for transfer of ionic information
skeletal
blank muscle has no gap junctions
cardiac
blank muscle has the most mitochondria out of all the muscle types
skeletal, bone, axial, appendicular
blank muscle is attached to blank and is responsible for movement of the blank and blank skeleton, and for maintenance of body position and posture visceral blank muscle is morphologically identical, but is restricted to blank tissues, including the tongue, pharynx, upper part of the esophagus, and the diaphragm
extraocular
blank muscles three pairs of muscles around each eye that enable us to move our eyes very rapidly and accurately and keep the eyes always pointed in the same direction
skeletal, periphery
blank muscles are multinucleated cells - syncytium nuclei are found in the blank of the cell
smooth
blank muscles have no sarcomeres
longitudinal
blank section of skeletal muscle you can see the perimysium, and individual fascicles, but you cannot see the muscle fibers, but you can see the dark-staining nucleus
intermediate, white
blank skeletal muscle fiber fast
white
blank skeletal muscle fiber glycolytic fiber
red
blank skeletal muscle fiber oxidative fiber
intermediate
blank skeletal muscle fiber oxidative-glycolytic fiber
red
blank skeletal muscle fiber slow
tropomyosin
blank wraps around blank, preventing blank binding, until blank ions are released from the sarcoplasmic reticulum, allowing contraction of skeletal muscles
alpha-actinin
blank-blank a protein that bundles actin into parallel arrays and anchors actin to Z lines
alpha-actinin
blank-blank protein that anchors thin filaments, or actin, at the Z line
oxidative-glycolytic
blank-blank fibers utilize a substantial reliance on both glycolysis and oxidative phosphorylation for energy for contraction
striated, one, centrally, branched, intercalated discs, desmosomes, gap, mitochondria, 40%, I, autonomic
cardiac muscle characteristics - blank - presence of sarcomeres - blank nuclei per cell, this is blank located - cells are blanked - joined by blank blank with blank and other adherent junctions for firm adhesion, and with blank junctions - blank occupy up to blank% of the cell volume, higher than in slow oxidative skeletal muscle (type blank) fibers - innervated by the blank nervous system, involuntary contraction
Purkinje fibers, myocytes, plasma, voltage, Na+, Na+, T tubules, voltage, DHSRs, T tubules, Ca2+, Ca2+, cytoplasm/sarcoplasm, RyR2 (different from RyR1 in skeletal muscle), Ca2+, sarcoplasmic reticulum, Ca2+, sarcoplasmic reticulum, Ca2+, sarcoplasm, Ca2+, Ca2+, myofilaments, TnC, troponin, actomyosin, Ca2+, terminal cisternae, sarcoplasmic reticulum, calsequestrin
cardiac muscle contraction process steps 1) contraction of a cardiac muscle fiber initiates when the cell membrane depolarization traveling along blank blank reaches its destination in cardiac blank 2) general depolarization spreads over the blank membrane of the muscle cell causing the opening of blank-gated blank channels; blank ions enter the cell 3) general depolarization continues via membranes of the blank blank 4) blank-sensor proteins (blank) in the plasma membrane of blank blank change their conformation into functional blank ion channels 5) rise in the blank ions in the blank opens the blank-gated blank-release channels in the blank blank 6) blank ions are rapidly released from the blank blank and increases the pool of blank ions that entered the blank through the blank ion channels in the plasma membrane 7) accumulated blank ions diffuse to the blank, where they bind to the blank portion of the blank complex 8) the blank cross-bridge cycle is similar to that of skeletal muscle - is initiated 9) blank ions are returned to the blank blank of the blank blank, where it is concentrated and captured by blank (a Ca2+ binding protein)
one, terminal cisternae, diad, diads, Z lines
cardiac muscle fiber structure - individual cells - sarcomeres and T tubules are different in that each T tubule is associated with blank number of blank blank (instead of 2) and so they are referred to as a blank instead of a triad these blank are located near the blank blank (instead of the A and I band boundaries of sarcomeres)
fusiform, gap, thin, thick, thin, alpha-actinin, dense, sarcolemma, sarcoplasmic reticulum, caveolae, Ca2+, actin, Ca2+-calmodulin, myosin light-chain kinase, MLCK, MLCK, phosphorylation, myosin
characteristics of smooth muscle - individual, small, blank (tapering) cells, communicate by numerous blank junctions - blank and blank filaments do NOT form sarcomeres - NO striations - blank actin filaments attach to blank-blank located in blank bodies that are located throughout the sarcoplasm and near the blank; contraction causes cells to shorten INDIVIDUALLY - blank blank is less well-organized in smooth muscle fibers, and there is no T tubule system; instead, invaginations (blank) contain the major ion channels that control blank ion release from the sarcoplasmic reticulum moreover, smooth muscle blank filaments are NOT associated with troponin and tropomyosin; instead, contraction is initiated by 1) blank-blank complex activates blank blank-blank blank (blank) 2) blank adds a phosphate group (or does blank) to blank blank of blank by the blank blank-blank blank (blank) after blank activation by a blank ion - blank complex
one, centrally, autonomic, hormones, epinephrine, norepinephrine, oxytocin, uterine
characteristics of smooth muscle - unstriated - blank nucleus per cell, blankly located - largely controlled/innervated by the blank nervous system - in addition, smooth muscle cells may be stimulated or inhibited by blank (ex. blank and blank) - also blank is a potent stimulator of smooth muscle contraction, and its release by the posterior pituitary plays an essential role in blank contraction during parturition
connexin 43, arrhythmias, hypertrophic cardiomyopathy, ischemic cardiomyopathy, arrhythmias, hypertrophic cardiomyopathy, ischemic cardiomyopathy
clinical relevance: blank blank dysfunction and disorganization in heart disease can lead to blank, blank blank, or blank blank leads to dysfunction and disorganization of this gene blank - reduction electrical coupling - reduction conduction velocity - distribution over myocyte surfaces - intracellular calcium overload blank - decrease of genetic expression - reduction of genetic mRNA - change in the heart conduction -- thickening of the left ventricular wall blank blank - closure of gap junctions - increase of cytosolic Ca2+ ions - reduction of ATP - alterations in genetic phosphorylation - electrical uncoupling
epimysium, collagen type I, collagen type III
connective tissue in skeletal muscle - entire gross muscle is surrounded by connective tissue called blank (made up of blank blank blank and blank blank blank)
perimysium, collagen type I
connective tissue in skeletal muscle - fascicles within gross muscle are surrounded by connective tissue called blank (made up of blank blank blank)
endomysium, collagen type I, collagen type III
connective tissue in skeletal muscle - individual muscle fibers or cells are surrounded by connective tissue called blank (made up of blank blank blank and blank blank blank)
fascicle, perimysium, muscle fibers, epimysium
cross section skeletal muscle F = ? P = ? MF = ? E = ?
parasympathetic
decelerating heartbeat impulses arrive via blank nervous system
desmin
desmosomes join with the sarcomere actin via intermediate filaments called blank
blood vessels, gastrointestinal tract, urogenital tract, respiratory tract, arrector pili
distribution of smooth muscle - walls of blank blank - walls of blank blank (esophagus, stomach, small intestine, large intestine) - walls of blank blank (bladder, urethra, uterus) - walls of blank blank (trachea, bronchi) - blank blank muscle in skin
attachment, release, bending, force generation (I-III), and reattachment
each cross-bridge cycle consists of five stages list them
endothelium, connective, smooth
endocardium made up of blank, blank tissue, and blank muscle
mesothelial, visceral pericardium, connective, adipose
epicardium a single layer of blank cells (blank blank) and underlying blank tissue and blank tissue
alpha-actinin
fascia adherens join the sarcomere actin directly through the blank-blank proteins via plasma membrane
RyR1 ryanodine
in an EM, it is shown that there is a blank blank receptor in the skeletal muscle triads which are gated Ca2+ release channels IN RESPONSE TO ACTION POTENTIAL, THEY OPEN AND RELEASE CA2+ FROM THE SARCOPLASMIC RETICULUM INTO THE SARCOPLASM
relaxed, contracted, I, thin, thick, A
in blank muscle, the sarcomere is from Z disc to Z disc and everything is separated in blank muscle, the blank band is decreased in length and Z disc to Z disc sarcomere distance is decreased as well - the blank filaments are pulled over the blank filaments; the blank band does not change during contraction
desmosomes, macula adherens, desmosomes, gap junctions
intercalated disks are composed of blank, which are also referred to as blank blank the blank are found in the transfer sections of these discs the blank blank are found on the lateral components of the intercalated disks
IIa
intermediate skeletal muscle fiber Type blank fiber
endocardium, myocardium, epicardium
layers of heart
fascicle
muscle blank is composed of muscle fibers
fiber
muscle blank is composed of myofibrils
myofibril
muscle blank is composed of myofilaments
calcium, ATP, acetylcholine
muscles contract due to the presence of blank ions, blank as energy driver, and blank as neurotransmitter via NEUROMUSCULAR JUNCTION
actin, ATP, ATPase, light
myosin head contains blank-binding sites, blank-binding sites (there is blank activity here), and one of each blank chain on each head
skeletal, cardac
only blank and blank muscles have sarcomeres and therefore striations - for muscle tissue contraction
striations, branched, intercalated discs
photomicrograph of longitudinally sectioned cardiac muscle cardiac muscle has cross blank and is composed of elongated, often blank cells joined to each other by blank blank UNIQUE TO CARDIAC
mitochondria, Z disc/Z line, A band, I band, M line within H zone
practice question of skeletal muscle labeling A = B = C = D = E =
myoglobin, mitochondria, slow, weaker, slower
red (slow, oxidative fibers (type I)) - more blank - more blank organelles - blank-twitch fibers - blanker contractions - blanker to fatigue
I
red skeletal muscle fiber Type blank fiber
myoglobin
red skeletal muscle fibers are RED because they contain blank
sinoatrial node, atrioventricular node, atrioventricular bundle, accelerating, sympathetic, decelerating, parasympathetic
regulation of cardiac contractility - heart has a conduction system of modified cardiac myocytes in blank blank, blank blank, and blank blank (of His) - blank heart beat impulses arrive via blank nervous system - blank heart beat impulses arrive via the blank nervous system (part of the blank nerve)
T tubules, 2, terminal cisternae
sarcolemma has transverse tubular foldings (blank blank) associated with blank number of blank blank: an action potential directly causes release of blank ions from the sarcoplasmic reticulum
skeletal, striated, syncytium, single, junctions, spinal
skeletal muscle characteristics - blank - presence of sarcomeres - many nuclei per cell - blank (fiber) - blank cells - no cell-to-cell blank - innervated by blank nerves - voluntary contraction
nucleus, myofibril, sarcolemma, mitochondria, sarcoplasmic reticulum
skeletal muscle fiber cross section - TEM A = B = C = D = E =
muscularis externa, circularly, spiral, longitudinally, dense irregular
smooth muscle, small intestine H&E stain blank blank consists of 2 concentric layers of smooth muscle inner layer is described as a blank-oriented layer outer layer form a loose blank or blank-oriented layer the connective tissue here is blank blank connective tissue
contracted, collagen, dense
smooth muscle, small intestine H&E stain the nuclei exhibit an undulating or wavy form, indicating that the cells are PARTIALLY blank the connective tissue has blank fibers and blank connective tissue
tropomyosin, troponin
the thin filament is wound around by a blank in skeletal muscles, when calcium ions are released upon neurostimulation, they bind blank
myosin II
thick filaments are bundles of blank blank
myosin II, 2, 4, 4, 2, essential, regulatory, 1, myosin
thick filaments are made up of blank blank (510 kDa), which is composed of blank polypeptide heavy chains (222 kDa each) and blank light chains within the blank number of light chains, there are blank types: blank (18 kDa) and blank (22 kDa) blank molecules of each light chain type is present in association with each blank head
actin, titin
thin filaments are composed largely of blank also there is some blank
actin
thin filaments are composed of blank
TnC, TnI, TnT
three subunits of troponin
TnC
troponin C
IIb
type blank fiber characteristic fast rate of fatigue
IIa, IIb
type blank fiber characteristic fast speed of contraction
IIb
type blank fiber characteristic high glycogen content
IIb
type blank fiber characteristic high glycolytic enzyme activity
I, IIa
type blank fiber characteristic high myoglobin content (red fibers)
IIa, IIb
type blank fiber characteristic high myosin-ATPase activity
IIa
type blank fiber characteristic intermediate diameter
IIa
type blank fiber characteristic intermediate glycogen content
IIa
type blank fiber characteristic intermediate glycolytic enzyme activity
IIa
type blank fiber characteristic intermediate rate of fatigue
IIa
type blank fiber characteristic intermediate size of motor unit
IIb
type blank fiber characteristic large diameter
IIb
type blank fiber characteristic large size of motor unit
I
type blank fiber characteristic low glycogen content
I
type blank fiber characteristic low glycolytic enzyme activity
IIb
type blank fiber characteristic low myoglobin content (white fibers)
I
type blank fiber characteristic low myosin-ATPase activity
IIb
type blank fiber characteristic major source of ATP: anaerobic glycolysis
I, IIa
type blank fiber characteristic major source of ATP: oxidative phosphorylation
I, IIa
type blank fiber characteristic numerous capillaries
I, IIa
type blank fiber characteristic numerous mitochondria
I
type blank fiber characteristic slow rate of fatigue
I
type blank fiber characteristic slow speed of contraction
I
type blank fiber characteristic small diameter
I
type blank fiber characteristic small size of motor unit
IIb
type blank fiber characteristic sparse capillaries
IIb
type blank fiber characteristic sparse mitochondria
IIb
type blank fiber characteristic typical major locations: extraocular muscles
IIa
type blank fiber characteristic typical major locations: major muscles of legs
I
type blank fiber characteristic typical major locations: postural muscles of back
skeletal, cardiac, smooth
types of muscle tissue
subendocardial
under or below the inner layer of the heart
TnC, troponin, tropomyosin, actin, tropomyosin, F-actin, myosin
when calcium is released to initiate contraction in skeletal muscle, it binds to the blank component of blank then there is a shift of blank along blank it makes the head move, and blank moves onto the blank-blank, exposing the blank-binding site, allowing cross bridges to form
less, fewer, fast, stronger, quicker
white (fast, glycolytic fibers (type IIb)) - blank myoglobin and blank mitochondria - blank-twitch fibers - blanker contractions - blanker to fatigue
IIb
white skeletal muscle fiber Type blank fiber
attachment, myosin, actin, ATP, rigor
STAGE 1 of contraction cycle: blank at the beginning of the contraction cycle, the blank head is tightly bound to the blank molecule blank (Driving force) is absent this whole look is called the blank configuration
release, ATP, myosin, myosin, actin
STAGE 2 of contraction cycle: blank blank binds to the blank head, inducing a conformational change, which causes the blank to uncouple from blank
bending, myosin, ATPase, ATP -> ADP + Pi, myosin
STAGE 3 of contraction cycle: blank blank has blank enzymatic activity and so it hydrolyzes blank -> blank + blank blank head BENDS during this reaction
force generation, myosin, Pi, ADP, myosin, power stroke, actin, H
STAGE 4 of contraction cycle: blank blank blank head releases blank as blank is released as well, the blank head generates a force as it returns to its original position - this movement is called a BLANK BLANK during this, the blank is pulled along towards the middle, or the blank zone of the sarcomere
reattachment, myosin, H zone, actin (thin filaments), A
STAGE 5 of contraction cycle: blank because the blank heads are arranged as mirror images on either side of the blank blank (via antiparallel arrangement), after the power stroke, this action pulls the blank into the blank band, thus shortening the sarcomere
axon, motor, neuromuscular junction, acetylcholine, ACh, synaptic cleft, ACh, Na+, sarcolemma, voltage, Na+, Na+, sarcolemma, T tubules, voltage, T tubules, triads, T tubules, sarcoplasmic reticulum, gated Ca2+, voltage, Ca2+, sarcoplasmic reticulum, sarcoplasm, Ca2+, myofilaments, TnC, troponin, actomyosin, Ca2+, terminal cisternae, sarcoplasmic reticulum, calsequestrin
steps of SKELETAL MUSCLE FIBER CONTRACTION INITIATION 1) contraction of skeletal muscle fiber is initiated when a nerve impulse traveling along the blank of a blank neuron arrives at the blank blank 2) the nerve impulse prompts the release of blank (blank) into the blank blank that binds into blank-gated blank ion channels, causing local depolarization of the blank 3) blank-gated blank channels open, and blank ions enter the cell 4) general depolarization spreads over the plasma membrane of the muscle cell, aka the blank, and continues via the membranes of the blank blank 5) blank sensor proteins in the plasma membrane of the blank blank change their conformation 6) at the muscle cell blank, the blank blank are in close contact with the lateral enlargements of the blank blank, where blank blank-release channels, called blank (blank) receptors, are activated by the conformational changes of blank-sensor proteins 7) blank ions are rapidly released from the blank blank into the blank 8) blank ions diffuse to the blank, where it binds to the blank portion of the blank complex 9) the blank cross-bridge contraction cycle is initiated (MORE ON THIS LATER) 10) blank ions are returned to the blank blank of the blank blank and captured by blank
T tubule, terminal cisternae, triad, A, I
the blank blank and blank blank is referred to as a blank they encircle each myofibril near the blank and blank band boundaries of sarcomeres
