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Muscle Test

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porschefan1's version from 2017-10-30 01:49

Section 1

Question Answer
Is muscle an organ?Yes
SarcolemmaMuscle cell membrane
Test-Muscle cell is aMuscle fiber
Test-MyofiberMuscle cell
Skeletal muscleStriated & voluntary
Cardiac muscleStriated & involuntary, also has intercalculated disks
Smooth muscleNon striated & involuntary, found in walls of hollow organs such as blood vessels, intestines, stomach etc.
Shape of smooth musclespindle
memorize

Section 2

Question Answer
Excitabilityresponsiveness, ability to respond to nervous stimuli
Contractilityshorten
Extensibilitylong, ability to be stretched
Elasticityability to recoil to resting length
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Section 3

Question Answer
Features of skeletal musclenerve/blood supply, connective tissue sheaths, attachments (bones/other muscles)
Contracting muscles require huge amounts of oxygen and nutrients, also remove waste products such as lactic acid
Connective tissue sheaths includeepimysium, perimysium, endomysium
Epimysiumdense irregular connective tissue surrounding entire muscle
perimysiumfibrous connective tissue surrounding fascicles
fasciclesgroups of muscle fibers
endomysiumfine areolar connective tissue surrounding each muscle fiber
memorize

Section 4

Question Answer
Muscles attach to bone in 2 placesinsertion/origin
Insertionattachment to movable bone
originattachment to immovable or less movable bone
direct (fleshy) attachmentepimysium fused to periosteum of bone or perichondrium of cartilage
indirectconnective tissue wrappings extend beyond muscle as tendon or aponeurosis
aponeurosistough connecting sheet connecting muscle to muscle (6 pack)
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Section 5

Question Answer
skeletal muscle fiberslong, cylindrical cells that contain multiple nuclei
sarcolemmamuscle fiber plasma membrane
sarcoplasmmuscle fiber cytoplasm
muscle fibers containglycosomes for glycogen storage (animal starch) and myoglobin for O2 storage
memorize

Section 6

Question Answer
Myofibrildensely packed rod like elements, accounts for 80% of muscle cell volume, will have more or less depending on use
myofibril featuresstriations, sarcomeres, myofilaments, molecular composition of myofilaments
striationslight and dark stripes along length of each myofibril
a bandsdark regions, thick
i bandslight, thin, actin
z disk (line)separates and defines a sarcomere, squiggly line in middle of i band
Test-What is the functional unit of muscleSarcomere
sarcomere's containA band with half an i band at each end, area between z disks
memorize

Section 7

Question Answer
actin myofilamentsthin, extend across i band and partway in A band, anchored to Z discs
myosin (protein) myofilamentsthick, extend length of A band, connect at M line
what is the difference between myofibrils and myofilaments?myofilaments are small filaments within myofibrils
myosin (protein) contains2 heavy and 4 light polypeptide chains
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Section 8

Question Answer
Step 1 of pre-cross bridge cycletropomyosin covers actin holes when calcium is low
Step 2calcium binds to troponin
Step 3troponin changes shape moving tropomyosin to uncover actin
beginning of pre-crossbridge cyclewhen an electrical impulse passes by, t tubule changes shape, causes SR to change shape, releases calcium into cytoplasm (sarcoplasm) (final go signal for muscle contraction)
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Section 9

Question Answer
Step 1 of cross bridge cyclemyosin head bonds to actin forming crossbridge between thick and thin filaments. ADP and inorganic phosphate attached to myosin from previous cross bridge cycle
Step 2myosin head pivots using energy previously stored called power stroke. Pulls actin thin filament toward center of sarcomere. ADP is released.
Step 3ATP binds, triggers breaking of cross bridge
Step 4cocking of myosin head, ATP hydrolysis turns into ADP and binds with Phosphate. That energy is stored for next cycle.
memorize

Section 10

Question Answer
Sarcoplasmic Reticulumnetwork of smooth endoplasmic reticulum tubules surrounding each myofibril, stores and releases calcium(CA2)
sarcolemma muscle cell membrane
t tubulesformed by protrusion of sarcolema deep into cell interior
t tubules allowincrease in muscle fiber's surface area, allow electrical nerve transmissions deep in muscle fiber. penetrate at A-i band junction
Triadarea formed from terminal cistern of 1 sarcomere, t tubule and terminal cistern of next sarcomere
sliding filament model of contractionduring contraction, thin filaments slide past thick filaments, causing actin and myosin to overlap more, neither change length
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Section 11

Question Answer
4 steps must occur for skeletal muscle to contract1. nerve stimulation. 2. action potential generated in sarcolemma. 3. AP propagated along sarcolemma. 4. intracellular calcium levels rise briefly
Action Potentiala nerve impulse
steps 3 and 4 referred to asexcitation(nervous)-contraction(muscle) coupling
skeletal muscles are stimulated by somatic (general term for muscle and skin) motor neurons
axonlong threadlike extensions of motor neurons traveling from central nervous system to skeletal muscle
axon branches end on muscle fiber and connect toneuromuscular junction or motor end plate
sympatic cleftaxon terminal and muscle fiber are separated by this gel-filled space
synaptic vesiclesstores stuff within axon terminals
synaptic vesicles containneurotransmitter called Acetylcholine (ACh)
many toxins, drugs and diseases interfere with events at theneuromuscular junction
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