BSC 215 Exam 3 - O Shields-Study
Guide Questions and Actual Answers
2026-2027 Updated.
What makes up muscle tissue? - Answer cells and extracellular matrix
What are the 3 types of muscle tissue? - Answer -skeletal
-cardiac
-smooth
What two muscles cells are striated? - Answer skeletal and cardiac
skeletal muscle cells - Answer long, multinucleated and connected to nerves
cardiac muscle cells - Answer shorter, uni or binucleated, branched, involuntary, connected to
each other by gap junctions
smooth muscle cells - Answer short, spindle shaped, unnucleated, connected to each other by
gap junctions
What makes up the extracellular matrix of muscle tissue? - Answer endomysium
endomysium - Answer holds muscle cells together within muscle tissue
What are the five characteristics of muscle cells? - Answer -contractility: ability of protein
fibers within myocytes to draw together (create force)
-excitability: responds to stimuli
-conductivity: conduct stimulus
-extensibility: can be stretched up to 3x resting length
-elasticity: ability to regain original state after stretching
What are the structure of muscle cells? (myocytes) - Answer myocyte (muscle cell)
-sarcoplasm: myocytes cytoplasm
-sarcolemma: myocytes plasma membrane
-sarcoplasmic reticulum: modified endoplasmic reticulum
,What does the SR form? - Answer web-like network surround myofibrils; also varies in
structure in the different types of muscle tissue
myofibrils - Answer -cylindrical organelles - hundreds to thousands in each myocyte- 50-80%
of cell volume
-made up of bundle of specialized proteins that allow for contraction
-other organelles like mitochondria are packed between these
epimysium - Answer surrounds muscle and continues as tendons
perimysium - Answer collects cells and endomysium into fascicles, continues as tendons
Are skeletal muscles considered an organ? - Answer yes
What makes muscle cells unique? - Answer -skeletal muscle fiber
-huge and super long, cylindrical cells
-striated in skeletal and cardiac muscle tissue
-multiple nuclei
transverse tubules (T-tubules) of skeletal muscle fiber - Answer deep inward extensions of
sarcolemma; surround each myofibril
-form tunnel-like network within muscle fibers
-continuous with exterior of cell; filled with extracellular fluid
terminal cisternae - Answer enlarged sections of sarcoplasmic reticulum; flank each T-tubule
triad - Answer two terminal cisternae plus corresponding T-tubule
What are 3 types of myofilaments? - Answer -thick
-thin
-elastic
thick filaments - Answer bundle of contractile protein myosin
thin filaments - Answer proteins actin, tropomyosin, and troponin
, elastic filaments - Answer single, massive spring-like structural protein (titin)
-stabilizes myofibril structure
-resists excessive stretching (sliding too far)
What are the 5 different filament proteins? - Answer -actin
-myosin
-titin
-tropomyosin
-troponin
light and dark bands have ------ ----- - Answer specific regions
I band - Answer only in thin filaments (actin)
Z disc - Answer in the middle of the I band and composed of structural proteins that:
-anchor thin filaments in place and to one another
-serve as attachment points for elastic filaments
-attach myofibrils to one another across entire diameter of muscle fiber
A band - Answer contains zone of overlap with both thick and thin filaments
-generate tension during contraction
H zone - Answer middle of A band where only thick filaments exist
M line - Answer dark line in middle of A band
-structural proteins hold thick filaments in place
-serve as anchoring point for elastic filaments
Where does the sarcomere functional contractile unit occur? - Answer between 2 Z discs
Where do actin filaments slide along and what do they pull? - Answer Actin filaments slide
along myosin towards the M line, pulling Z-discs closer together
Guide Questions and Actual Answers
2026-2027 Updated.
What makes up muscle tissue? - Answer cells and extracellular matrix
What are the 3 types of muscle tissue? - Answer -skeletal
-cardiac
-smooth
What two muscles cells are striated? - Answer skeletal and cardiac
skeletal muscle cells - Answer long, multinucleated and connected to nerves
cardiac muscle cells - Answer shorter, uni or binucleated, branched, involuntary, connected to
each other by gap junctions
smooth muscle cells - Answer short, spindle shaped, unnucleated, connected to each other by
gap junctions
What makes up the extracellular matrix of muscle tissue? - Answer endomysium
endomysium - Answer holds muscle cells together within muscle tissue
What are the five characteristics of muscle cells? - Answer -contractility: ability of protein
fibers within myocytes to draw together (create force)
-excitability: responds to stimuli
-conductivity: conduct stimulus
-extensibility: can be stretched up to 3x resting length
-elasticity: ability to regain original state after stretching
What are the structure of muscle cells? (myocytes) - Answer myocyte (muscle cell)
-sarcoplasm: myocytes cytoplasm
-sarcolemma: myocytes plasma membrane
-sarcoplasmic reticulum: modified endoplasmic reticulum
,What does the SR form? - Answer web-like network surround myofibrils; also varies in
structure in the different types of muscle tissue
myofibrils - Answer -cylindrical organelles - hundreds to thousands in each myocyte- 50-80%
of cell volume
-made up of bundle of specialized proteins that allow for contraction
-other organelles like mitochondria are packed between these
epimysium - Answer surrounds muscle and continues as tendons
perimysium - Answer collects cells and endomysium into fascicles, continues as tendons
Are skeletal muscles considered an organ? - Answer yes
What makes muscle cells unique? - Answer -skeletal muscle fiber
-huge and super long, cylindrical cells
-striated in skeletal and cardiac muscle tissue
-multiple nuclei
transverse tubules (T-tubules) of skeletal muscle fiber - Answer deep inward extensions of
sarcolemma; surround each myofibril
-form tunnel-like network within muscle fibers
-continuous with exterior of cell; filled with extracellular fluid
terminal cisternae - Answer enlarged sections of sarcoplasmic reticulum; flank each T-tubule
triad - Answer two terminal cisternae plus corresponding T-tubule
What are 3 types of myofilaments? - Answer -thick
-thin
-elastic
thick filaments - Answer bundle of contractile protein myosin
thin filaments - Answer proteins actin, tropomyosin, and troponin
, elastic filaments - Answer single, massive spring-like structural protein (titin)
-stabilizes myofibril structure
-resists excessive stretching (sliding too far)
What are the 5 different filament proteins? - Answer -actin
-myosin
-titin
-tropomyosin
-troponin
light and dark bands have ------ ----- - Answer specific regions
I band - Answer only in thin filaments (actin)
Z disc - Answer in the middle of the I band and composed of structural proteins that:
-anchor thin filaments in place and to one another
-serve as attachment points for elastic filaments
-attach myofibrils to one another across entire diameter of muscle fiber
A band - Answer contains zone of overlap with both thick and thin filaments
-generate tension during contraction
H zone - Answer middle of A band where only thick filaments exist
M line - Answer dark line in middle of A band
-structural proteins hold thick filaments in place
-serve as anchoring point for elastic filaments
Where does the sarcomere functional contractile unit occur? - Answer between 2 Z discs
Where do actin filaments slide along and what do they pull? - Answer Actin filaments slide
along myosin towards the M line, pulling Z-discs closer together
