Muscular Tissue Self-Quiz Flashcards
Wasting of muscle is …
Muscular atrophy
Somatic motor neuron and all of the muscle fibers it stimulates is a …
Motor unit
The replacement of skeletal muscle fibers with scar tissue is …
Fibrosis
The synaptic end bulbs of somatic motor neurons contain synaptic vesicles filled with …
Acetylcholine
Ability of muscle cells to respond to stimuli by producing electrical impulses:
Excitability
Sequence of events resulting in muscle contraction:
Nerve impulse,
release of acetylcholine,
muscle action potential,
release of calcium ions from sarcoplasmic reticulum,
calcium ion binding to troponin,
power stroke with actin and myosin binding and release
The brief delay between stimulus and contraction of muscle is …
Latent period
Contractile motor protein that binds to actin
Myosin
Regulatory protein that blocks myosin from binding to actin while muscle is relaxed
Tropomyosin
Contractile protein containing myosin binding sites
Actin
Regulatory protein that hold tropomyosin in place
Troponin
Protein within sacroplasmic reticulum that binds with calcium
Calsequestrin
Structural protein that connects Z-disc to M-line; highly elastic and extensible
Titin
Structural protein that forms the M-line by binding to titin and holding myosin ends together
Myomesin
Structural protein that forms the Z-disc, binding to ends of titin and ends of actin
Alpha-actinin
Structural protein wrapped around thin filament anchoring them to Z-disc
Nebulin
Structural protein that links sarcomeres to membrane proteins in the sarcolemma
Dystrophin
A band
Part of sarcomere that extends the entire length of myosin thick filaments and does not change in length during contraction;
part of thin filaments are found here
I band
The part of sarcomere that does not include any myosin thick filaments, and shortens with muscle contraction
H zone
Center part of A band that contains only myosin thick filaments
M line
Midline of sarcomere where myosin ends meet one another
Z disc
Found between sarcomeres
Decreased tension in the sarcomere occurs when …
over stretched or too short
Myosin heads cannot contact actin
Maximal tension occurs when what is optimized?
Zone of overlap,
where the myosin and actin filaments maximize their contact
Four sources of ATP for muscle contraction
Creatine phosphate,
glycolysis,
anaerobic cellular respiration,
aerobic cellular respiration
Is ATP required to bind myosin to actin
OR to release myosin from actin?
Both!
ATP hydrolysis is required to reorient myosin heads so they can bind to actin,
and ATP binds to the myosin head to detach is from the actin.
The contraction cycle continues as long as ATP and sufficient calcium ions are available
Epimysium
Outermost connective tissue that surrounds entire muscle
Perimysium
Dense irregular connective tissue separating groups (fascicles) of muscle fibers within a muscle
Endomysium
Areolar connective tissue surrounding individual muscle fibers
Sarcomere
Contracting unit of skeletal muscle fiber
Synapse between motor neuron and muscle fiber
Neuromuscular junction
Red-coloured oxygen-binding protein found only in muscle fibers
Myoglobulin
Releases oxygen when needed by mitochondria for ATP production
Sarcoplasmic reticulum
Stores calcium ions within muscle cells
Sarcolemma
Plasma membrane of muscle fiber
Sarcoplasm
Cytoplasm of muscle fiber
Has intercalated discs
Cardiac muscle
Striated muscle
Skeletal and cardiac
Contraction begin slowly and lasts for long periods
Smooth muscle
Extended contraction due to prolonged calcium delivery from sarcoplasmic reticulum and interstitial fluid
Cardiac muscle
Autorhythmicity only exhibited in what type of muscle?
Cardiac and visceral smooth
Which muscle type has greatest capacity for regeneration?
Smooth muscle, via pericytes, stem cells found near capillaries and small veins
Regulatory proteins for cardiac muscle tissue
Troponin and tropomyosin, same as for skeletal muscle
Calmodulin
Regulator protein for smooth muscle tissue
Sustained contraction of muscle
Fused (complete) tetanus
Larger contractions resulting from stimuli arriving at different times
Wave-summation
Concentric, isometric, eccentric
Shortening,
same length,
lengthening muscle during contraction
Sustained, but wavering contraction with partial relaxation between stimuli
Unfused (incomplete) tetanus
Continual involuntary activation of skeletal muscle gives …
Muscle tone
Recovery oxygen uptake
Amount of oxygen needed to restore the body’s metabolic conditions back to resting levels after exercise
Stress-relaxation response
Smooth muscle action maintaining contractile function even while stretched
