BSC 215 Exam #3- Lecture Questions
and Answers 2026 Updated.
skeletal muscle - Answer voluntary, long, cylindrical, multinucleate cells; obvious striations
cardiac muscle - Answer involuntary, short, branched, uni/bi-nucleated muscle cells; striated
smooth muscle - Answer short, spindle shaped, uni-nucleated cells with no striations;
involuntary
Contractibility - Answer ability of protein fibers within myocytes to draw together
Excitability - Answer ability to respond to stimuli
Conductivity - Answer ability to transmit an impulse
Extensibility - Answer ability to be stretched
Elasticity - Answer The ability of a material to bounce back after being disturbed
myocyte - Answer muscle cell
Sarcoplasm - Answer cytoplasm of a muscle cell
Sarcolemma - Answer plasma membrane of a muscle fiber
sarcoplasmic reticulum - Answer specialized endoplasmic reticulum of muscle cells; forms a
web-like structure around myofibrils & stores calcium
Endomysium - Answer Surrounds individual muscle fibers
Fasicle - Answer bundle of muscle fibers
Perimysium - Answer surrounds fascicles
, Epimysium - Answer covers the entire skeletal muscle and extends into tendon
Myofibrils - Answer Microscopic protein filaments that make up muscle cells.
transverse (T) tubules - Answer extensions of the cell membrane that surrounds each myofibril
terminal cisternae - Answer enlarged areas of the sarcoplasmic reticulum surrounding the
transverse tubules.
Triad - Answer two terminal cisternae and a T tubule
thick filaments - Answer composed of myosin
thin filaments - Answer composed of actin, troponin, tropomyosin
elastic filaments - Answer composed of titin; resists excessive stretching
I/light band - Answer only thin (actin) filaments present
Z disc - Answer in the I band; provides anchorage for thin filaments and elastic filaments
A/dark band - Answer zone of overlap with thick and thin filaments that generate tension
when contraction occurs
H zone - Answer The region at the center of an A band of a sarcomere that is made up of
myosin only. The H zone gets shorter (and may disappear) during muscle contraction.
M line - Answer Middle of sarcomere, holds thick filament in place
membrane potential - Answer The voltage across a cell's plasma membrane.
-85 mV - Answer resting membrane potential of a muscle cell
sodium-potassium pump - Answer A special transport protein in the plasma membrane of
animal cells that transports sodium out of the cell and potassium into the cell against their
concentration gradients.
and Answers 2026 Updated.
skeletal muscle - Answer voluntary, long, cylindrical, multinucleate cells; obvious striations
cardiac muscle - Answer involuntary, short, branched, uni/bi-nucleated muscle cells; striated
smooth muscle - Answer short, spindle shaped, uni-nucleated cells with no striations;
involuntary
Contractibility - Answer ability of protein fibers within myocytes to draw together
Excitability - Answer ability to respond to stimuli
Conductivity - Answer ability to transmit an impulse
Extensibility - Answer ability to be stretched
Elasticity - Answer The ability of a material to bounce back after being disturbed
myocyte - Answer muscle cell
Sarcoplasm - Answer cytoplasm of a muscle cell
Sarcolemma - Answer plasma membrane of a muscle fiber
sarcoplasmic reticulum - Answer specialized endoplasmic reticulum of muscle cells; forms a
web-like structure around myofibrils & stores calcium
Endomysium - Answer Surrounds individual muscle fibers
Fasicle - Answer bundle of muscle fibers
Perimysium - Answer surrounds fascicles
, Epimysium - Answer covers the entire skeletal muscle and extends into tendon
Myofibrils - Answer Microscopic protein filaments that make up muscle cells.
transverse (T) tubules - Answer extensions of the cell membrane that surrounds each myofibril
terminal cisternae - Answer enlarged areas of the sarcoplasmic reticulum surrounding the
transverse tubules.
Triad - Answer two terminal cisternae and a T tubule
thick filaments - Answer composed of myosin
thin filaments - Answer composed of actin, troponin, tropomyosin
elastic filaments - Answer composed of titin; resists excessive stretching
I/light band - Answer only thin (actin) filaments present
Z disc - Answer in the I band; provides anchorage for thin filaments and elastic filaments
A/dark band - Answer zone of overlap with thick and thin filaments that generate tension
when contraction occurs
H zone - Answer The region at the center of an A band of a sarcomere that is made up of
myosin only. The H zone gets shorter (and may disappear) during muscle contraction.
M line - Answer Middle of sarcomere, holds thick filament in place
membrane potential - Answer The voltage across a cell's plasma membrane.
-85 mV - Answer resting membrane potential of a muscle cell
sodium-potassium pump - Answer A special transport protein in the plasma membrane of
animal cells that transports sodium out of the cell and potassium into the cell against their
concentration gradients.
