muscles part 2

skeletal muscle tissue, blood vessels, nerve fibers, connective tissue

gross anatomy of the skeletal muscle:

• each skeletal muscle is an organ, made up of several kind of tissues: .. … …, … …., … … , and … …

one nerve, one artery, one or more veins

gross anatomy of the skeletal muscle:

• nerve and blood supply: in general, … … , ….. …., and … .. … .. serve each muscle

nerve stimulation, nerve ending, voluntary

gross anatomy of the skeletal muscle:

• unlike cells of cardiac and smooth muscle tissues, which can contract without … …, every skeletal muscle fiber is supply with a .. .. that controls its activity (…. control)

rich, energy, oxygen, nutrients, metabolic waste

gross anatomy of the skeletal muscle:

• skeletal muscle has a … blood supply → contracting muscle fibers require a huge amount of …. and ….. and …., as well as need to rid of large amounts of … ….

connective tissue sheaths, whole, bursting, strong

gross anatomy of the skeletal muscle:

• skeletal muscle tissues are wrapped by … … …, which support each cell and reinforce and hold together the muscle as a …., preventing the bulging muscles from …. during exceptionally …. contractions

epimysium, perimysium and fascicles, endomysium

what are the 3 connective tissue sheaths of skeletal muscle tissues?

epimysium

…. is an “overcoat” of dense irregular connective tissue that surrounds the whole muscle

dense irregular, whole

the epimysium is an overcoat of … … connective tissue that surrounds the …. muscle

fascicles, perimysium

• within each skeletal muscle, the muscle fibers are grouped into …….

• surrounding each fascicle is a layer of fibrous connective tissue called …., which contains blood vessels and fibers

endomysium, fine areolar

… is a sheath of connective tissue that surrounds each individual muscle fiber

• it consists of … … connective tissue

individual, fine areolar

the endomysium is a sheath of connective tissue that surrounds each …. muscle fibers

• it consists of …. …. connective tissue

from other muscles, other organs

what does the epimysium separate the whole skeletal muscle from?

from another fascicles

what does the perimysium separate the fascicle from?

from another skeletal muscle fiber

what does the endomysium separate the skeletal muscle fiber?

origin

the stationary immoveable or less moveable attachment of a muscle to a bone

insertion

the moveable attachment of a muscle to a bone

insertion, origin

when a muscle contracts, the …. moves toward the ….

continuous, join, muscle, bones

gross anatomy of the skeletal muscle:

• all of the connective tissue sheaths are … with one another, as well as with the tendons that …. …. to …..

contract, sheaths, moved

gross anatomy of the skeletal muscle:

• when muscle fibers ….., they pull on these …., which transmit the pulling force to the bone to be …..

elasticity

gross anatomy of the skeletal muscle:

• the sheaths contribute to the natural … of the muscle tissue

entry, exit, blood vessels, nerve fibers

gross anatomy of the skeletal muscle:

• the sheaths provide …. and …. routes for the … … and … … that serve the muscle

long, cylindrical, multiple, sarcolemma

microscopic anatomy of a skeletal muscle fiber:

• each skeletal muscle fiber:

  • is a …., … cell with … nuclei just beneath its … (or plasma membrane)

10 to 100 um, 30 cm

the skeletal muscle fiber is a huge cell with a diameter of …. to …. and a length up to …. long

sarcoplasm, myofibrils, sarcoplasmic reticulum, transverse tubules

what are the 4 unique parts for the skeletal muscle fiber?

glycosides, myogloblin

what does the sarcoplasm contain?

glycosomes

granules of stored glycogen that provide glucose during muscle contraction (in the sarcoplasm)

glycogen, glucose, contraction

the glycosomes in the sarcoplasm are granules of stored …. that provide …. during muscle …..

myoglobin

… is a red pigment that stores oxygen

red, oxygen

the myoglobin is a …. pigment that stores ….

myofibrils

• a single muscle fiber that contains hundreds to thousands of …… (1-2 um) that run parallel to its length

  • they account for about 80% of cellular volume

  • they also contain the contractile elements of the skeletal muscle fiber: the sarcomere, which contains even smaller structures called myofilaments

1,2, parallel, 80, sarcomere, myofilaments

a single muscle fiber contains hundred to thousands of myofibrils (….-….. um) that run …. to its length

• they account for about ….% of cellular volume

• myofibrils contain the contractile elements of the skeletal muscle fiber, the ….., which contains even smaller structures called ……

sarcolemma, sarcoplasm, terminal cisternae, sarcoplasmic reticulum

transverse tubules (T tubules):

• …. invaginates into the …. forming T tubules

• in either side of the T tubules are …. …, which are the enlargement of the … …..

dark A band, H zone, vertically, M line

the myofibrils contain a … … …, each has a lighter region called … …, each H zone is bisected …. by a dark line called the …. …

light I band, Z disc

the myofibrils also has a … … …, each has a midline called … …

sarcomere

the region of a myofibril between 2 successive Z disc is a …. (2 um long)

2 um

how long is a sarcomere?

thin

are thick or thin filaments present in the light band?

thick

are thick or thin filaments present in the H zone?

thick and thin filaments overlap

are thick or thin filaments present in the A band?

perpendicular, thick, M

in the H zone, proteins run …. to … filaments to form the … line

sarcomere

what is the functional unit of the skeletal muscle fiber?

thick, thin

what are the 2 types of myofilaments?

16 um

how long are the thick filaments in diameter?

myosin, 2, 4, polypeptide chains

the thick filaments are composed of the protein ……, which consists of … heavy and … light …. ….

tail, 2 globular heads

the myosin has a … attached by a flexible hinge to … … …

2 intertwined, heavy

the tail of the myosin consists of … … helical polypeptide ….. chains

2 light

the globular heads are associated with … … chains

actin-binding, ATP-binding, ATPase, splits, ATP, contraction

the globular head of the myosin contains:

• the …-….. sites

• the …. ….. sites

• ….. activity that … … to generate energy for muscle ….

7-8 um

how thick are the thin filaments?

filamentous actin, tropomyosin, troponin

what are the 3 thing that the thin filaments are composed of?

g-actin

the filamentous actin (F actin) is a polymer made by subunits of …..

polypeptide, actin, relaxed, blocks

the tropomyosin is a … that spiral around the …. filament and help stabilize it

• when the muscle is …., tropomyosin ….. the myosin-binding site of the actin → myosin head on the thick filament cannot bind to the thin filament

globular 3

troponin is a … … polypeptide complex

TnI, TnT, TnC

what are the 3 polypeptides of troponin?

inhibitory, actin

TnI is an … subunit that binds to …..

tropomyosin, position

TnT binds to …. and helps …. it on actin

calcium ions

TnC binds …. …..

TnI

… is an inhibitory subunit that binds to actin

TnT

….. binds to tropomyosin and helps position it on actin

TnC

… binds calcium ions

troponin, tropomyosin

both … and … help control the myosin-actin interactions involved in contraction

center, sarcomere, sides, myofilament band

myosin tails are arranged to point toward the … of the …, and the heads point to the …. of the … ….

tubules, longitudinal, myofibrils, H zone

the sarcoplasmic reticulum contains …. which run … along the …., communicating with each other at the … ….

sarcoplasmic reticulum

the … .. contains tubules which run longitudinally along the myofibrils, communicating with each other at the H zone

intracellular, calcium, contract

the sarcoplasmic reticulum regulates …. levels of …. and stores calcium and releases it on demand when the muscle fiber is stimulated to ……

sarcoplasmic reticulum

the … … regulates intracellular levels of calcium and stores calcium and releases it on demand when the muscle fiber is stimulated to contact

sarcolemma, A band, I band, terminal cisternae, sarcoplasmic reticulum

the t-tubules are made by protruding deep in the …. into the sarcoplasm at each … … - … … junction and on either sides of the t-tubules are … … which are enlargement of the … ….

t-tubules

the .-.. are made by protruding deep in the sarcolemma into the sarcoplasm at each A band-I band junction and on either side of this are terminal cisternae, which are enlargement of the sarcoplasmic reticulum

terminal cisternae, t-tubule, terminal cisternae

what made up a triad?

nerve-initiated electrical impulses, sarcolemma, sarcolemma, triads, calcium, sarcoplasmic reticulum

muscle contraction is controlled by …. - ….. …. … that travel along the ….

• because the t-tubules are a continuation of the …, t-tubules conduct electrical impulses to …, which signal for the release of …. form the …. …..

the skeletal muscle fiber must be activated upon nerve ending stimulation and after that a change in membrane potential occurs

physiology of the skeletal muscle fiber:

• what is the 1st step for a skeletal muscle fiber to contract?

the electrical impulse must generate a electrical current (called action potential) in its sarcolemma

physiology of the skeletal muscle fiber:

• what is the 2nd step for a skeletal muscle fiber to contract?

the action potential must be propagated along the sarcolemma

physiology of the skeletal muscle fiber:

• what is the 3rd step for a skeletal muscle fiber to contract?

calcium must be released from the sarcoplasmic reticulum, rise briefly in the sarcoplasm, providing the final stimulus for contraction (cross bridges of myosin)

physiology of the skeletal muscle fiber:

• what is the 4th step for a skeletal muscle fiber to contract?

nerve

the somatic motor neurons are ….. cells that activate skeletal muscle fibers

somatic motor neurons

the … … .. are nerve cells that activate skeletal muscle fibers

brain, spinal cord, axons, innervate

the somatic motor neurons are located in the … or … .., but their …. travel to the muscle cells they …..

somatic motor neurons

the … …. … are located in the brain or spinal cord, but their axons travel to the muscle cells they innervate

neuromuscular junction, end plate

each axon of the somatic motor neurons ending off several branches that collectively form a …. …. or … … with a single muscle fiber

presynaptic axon terminal, synaptic cleft, postsynaptic functional folds of the sarcolemma

the neuromuscular junction includes:

synaptic vesicles, neurotransmitter acetylcholine

within the axon terminal are … …, which contains the … .. (ACh)

motor unit

a … .. consists of one motor neuron and all the muscle fibers it innervates

one motor neuron, muscle fibers, innervates

a motor unit consists of … … .. and all the … … it ….

nerve impulse, axon, axon terminal, Ach, synaptic cleft

step 1 of the neuromuscular junction:

• when a … …. reaches the end of the …, the … … releases … into the …. ….

Ach, synaptic cleft, Ach receptors, sarcolemma, muscle fiber

step 2 of the neuromuscular junction:

• …. diffuses across the … … and attaches to the … … located in the …. of the … …

Ach, receptor, electrical, action potential

step 3 of the neuromuscular junction:

• … binding to … triggers …. events that generate an …. ….

acetyl cholinesterase

Ach effects finishes by … …, an enzyme located in the synaptic cleft

chemically gated channels, Na+, K+, in, out

generation of an action potential in a skeletal muscle fiber:

1) binding of Ach to its receptor at the neuromuscular junctions opens …. … …, that allow … and … to pass → Na+ is coming ….. and K+ is going ….

transient, membrane potential, interior, sarcolemma, negative, depolarization, end plate potential

generation of an action potential in a skeletal muscle fiber:

2) a … change in the … … occurs at the … of the .. becomes less … → …..

• initially, depolarization is a local event called an …. …. ….

end plate potential, -60 mv, action potential, voltage gated Na+ channels

generation of an action potential in a skeletal muscle fiber:

3) if the … .. .. reaches the threshold (… ….), an … .. is generated —> … … .. .. open by depolarization

Na+, electrochemical gradient

generation of an action potential in a skeletal muscle fiber:

• … enters following its … ….

action potential, sarcolemma, all, adjacent, voltage gated Na+ channels

propagation of the action potential:

1) the … … propagates along the length of the … in …. directions by spreading to …. membrane areas and opening … … .. …

repolarization

… is the restoring of the sarcolemma to its initial resting potential

restoring, sarcolemma, initial

repolarization is the … of the … to its …. resting potential

changes, membrane permeability

depolarization is a consequence of …. in …. ….

Na+, close, K+, open, out, negative

repolarization

• … channels … and … channels … —> since K+ is higher inside the cell than outside, K+ diffuses …. of the muscle fiber, restoring the …. charge inside

refractory, stimulated, repolarization

repolarization:

• during the depolarization, the muscle fiber is in a ….. period because the cell cannot be … again until … is complete

electrical, resting

repolarization restores the … conditions of the ….. state

repolarization

…. restores the electrical conditions of the resting state

Na+/K+ ATPase, ionic, resting

repolarization:

• the …. pump restores the … condition of the … state