Excitability - answerability to respond to stimuli
Contractility - answerability to shorten forcibly when stimulated
Extensibility - answerability to be stretched
Elasticity - answerability to recoil to resting length
muscles function - answerProduce movement
maintain posture and body position
stabilize joints
Generate heat as they Contract
skeletal muscle Features - answernerve and blood supply, connective tissue sheaths,
and attachments
Epimysium - answerdense irregular connective tissue surrounding entire muscle; may
blend with fascia
Perimysium - answerfibrous connective tissue that surrounds groups of muscle fibers
called fascicles
Endomysium - answerfine areolar connective tissue surrounding each muscle fiber
Muscles (organ) - answera muscle consists of hundreds to thousands of muscles cells,
plus connective tissue wrapping, blood vessels and nerve fibers
Fascicle - answera fascicle is a discrete bundle of muscles cells, segregated from the
rest of the muscles by a connective tissue sheath
Muscle Fiber - answera muscles fiber is elongated multinucleate cell; it has a banded
appearance
Sarcolemma - answermuscle fiber plasma membrane
Sarcoplasm - answermuscle fiber cytoplasm
, Muscle fiber characteristics - answerlong
cylindrical cells that contain multiple nuclei
-contains many glycosomes for glycogen storage
- as well as myoglobin of O2 storage
Myofibrils - answerdensely packed, rodlike elements
Striations - answerstripes formed from repeating series of dark and light bands along
length of each myofibril
A bands - answerdark regions, length of thick filaments
H zone - answerlighter region in midsection of dark A band
M line - answerline of protein (myomesin) that bisects H zone vertically
I bands - answera lighter regions, length of actin
Z line (disc) - answercoin-shaped sheet of proteins on midline of light I band
Sarcomere - answerthe smallest contractile unit of muscle fiber
-extends from one Z disc to the next
Myofilaments - answerOrderly arrangement of actin and myosin myofilaments within
sarcomere
actin filaments - answerthin filaments
Myosin - answerthick filament
elastic filaments - answer- composed of protein titin
-holds thick filaments in place; helps filaments recoil after stretch
Dystrophin - answerLinks thin filaments to proteins of sarcolemma
sacroplasmic reticulum - answernetwork of smooth endoplasmic reticulum tubules
surrounding each myofibril
- SR regulation of intracellular Ca levels
- Stores and releases Ca
T tubules - answerTube formed by protrusion of sarcolemma deep into cell interior
allow electrical nerve transmission to reach deep into the anterior of each muscle fiber
Triad - answerarea formed from terminal cistern of one sarcomere, T tubule, and
terminal cistern of neighboring sarcomere
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