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